EyeLink fMRI / MEG Publications
All EyeLink fMRI and MEG research publications (with concurrent eye tracking) up until 2023 (with some early 2024s) are listed below by year. You can search the publications using keywords such as Visual Cortex, Neural Plasticity, MEG, etc. You can also search for individual author names. If we missed any EyeLink fMRI or MEG articles, please email us!
2009 |
Naotsugu Tsuchiya; Farshad Moradi; Csilla Felsen; Madoka Yamazaki; Ralph Adolphs Intact rapid detection of fearful faces in the absence of the amygdala Journal Article In: Nature Neuroscience, vol. 12, no. 10, pp. 1224–1225, 2009. @article{Tsuchiya2009, The amygdala is thought to process fear-related stimuli rapidly and nonconsciously. We found that an individual with complete bilateral amygdala lesions, who cannot recognize fear from faces, nonetheless showed normal rapid detection and nonconscious processing of those same fearful faces. We conclude that the amygdala is not essential for early stages of fear processing but, instead, modulates recognition and social judgment. |
Verena Thaler; Karolina Urton; Angela Heine; Stefan Hawelka; Verena Engl; Arthur M. Jacobs Different behavioral and eye movement patterns of dyslexic readers with and without attentional deficits during single word reading Journal Article In: Neuropsychologia, vol. 47, no. 12, pp. 2436–2445, 2009. @article{Thaler2009, Comorbidity of learning disabilities is a very common phenomenon which is intensively studied in genetics, neuropsychology, prevalence studies and causal deficit research. In studies on the behavioral manifestation of learning disabilities, however, comorbidity is often neglected. In the present study, we systematically examined the reading behavior of German-speaking children with dyslexia, of children with attentional problems, of children with comorbid dyslexia and attentional problems and of normally developing children by measuring their reading accuracy, naming latencies and eye movement patterns during single word reading. We manipulated word difficulty by contrasting (1) short vs. long words with (2) either low or high sublexical complexity (indexed by consonant cluster density). Children with dyslexia only (DYS) showed the expected reading fluency impairment of poor readers in regular orthographies but no accuracy problem. In contrast, comorbid children (DYS + AD) had significantly higher error rates than all other groups, but less of a problem with reading fluency than DYS. Concurrently recorded eye movement measures revealed that DYS made the highest number of fixations, but exhibited shorter mean single fixations than DYS + AD. Word length had the strongest effect on dyslexic children, whereas consonant cluster density affected all groups equally. Theoretical implications of these behavioral and eye movement patterns are discussed and the necessity for controlling for comorbid attentional deficits in children with reading deficits is highlighted. |
Gary Feng; Kevin Miller; Hua Shu; Houcan Zhang Orthography and the development of reading processes: An eye-movement study of Chinese and English Journal Article In: Child Development, vol. 80, no. 3, pp. 720–735, 2009. @article{Feng2009a, As children become proficient readers, there are substantial changes in the eye movements that subserve reading. Some of these changes reflect universal developmental factors while others may be specific to a particular writing system. This study attempts to disentangle effects of universal and script-dependent factors by comparing the development of eye movements of English and Chinese speakers. Third-grade (English: mean age = 9.1 years |
Amanda L. Gamble; Ronald M. Rapee The time-course of attentional bias in anxious children and adolescents Journal Article In: Journal of Anxiety Disorders, vol. 23, no. 7, pp. 841–847, 2009. @article{Gamble2009, This study examined the time-course of attentional bias in anxious and non-anxious children and adolescents aged 7-17 years using eye movement as an index of selective attention. Participants completed two eye-tracking tasks in which they viewed happy-neutral and negative-neutral face pairs for 3000 and 500 ms, respectively. When face pairs were presented for 3000 ms eye movement data showed no evidence of an attentional bias at any stage of attentional processing. When face pairs were presented for 500 ms a bias in initial orienting occurred; anxious adolescents directed their first fixation away from negative faces and anxious children directed their first fixation away from happy faces. Results suggest that childhood anxiety is characterized by a bias in initial orienting, with no bias in sustained attention, although only for briefly presented faces. |
Lynn Huestegge; Ralph Radach; Daniel Corbic; Sujata M. Huestegge Oculomotor and linguistic determinants of reading development: A longitudinal study Journal Article In: Vision Research, vol. 49, pp. 2948–2959, 2009. @article{Huestegge2009a, We longitudinally assessed the development of oculomotor control in reading from second to fourth grade by having children read sentences with embedded target words of varying length and frequency. Additionally, participants completed oculomotor (pro-/anti-saccades) and linguistic tasks (word/picture naming), the latter containing the same item material as the reading task. Results revealed a 36% increase of reading efficiency. Younger readers utilized a global refixation strategy to gain more time for word decoding. Linguistic rather than oculomotor skills determined the development of reading abilities, although naming latencies of fourth graders did not reliably reflect word decoding processes in normal sentence reading. |
Brandon Keehn; Laurie A. Brenner; Aurora I. Ramos; Alan J. Lincoln; Sandra P. Marshall; Muller Ralph-Axel Brief report: Eye-movement patterns during an embedded figures test in children with ASD Journal Article In: Journal of Autism and Developmental Disorders, vol. 39, no. 2, pp. 383–387, 2009. @article{Keehn2009, The present study examined fixation frequency and duration during an Embedded Figures Test (EFT) in an effort to better understand the attentional and perceptual processes by which individuals with autism spectrum disorder (ASD) achieve accelerated EFT performance. In particular, we aimed to elucidate differences in the patterns of eye-movement in ASD and typically developing (TD) children, thus providing evidence relevant to the competing theories of weak central coherence (WCC) and enhanced perceptual functioning. Consistent with prior EFT studies, we found accelerated response time (RT) in children with ASD. No group differences were seen for fixation frequency, but the ASD group made significantly shorter fixations compared to the TD group. Eye-movement results indicate that RT advantage in ASD is related to both WCC and enhanced perceptual functioning. |
Korbinian Moeller; S. Neuburger; L. Kaufmann; K. Landerl; Hans-Christoph Nuerk Basic number processing deficits in developmental dyscalculia: Evidence from eye tracking Journal Article In: Cognitive Development, vol. 24, no. 4, pp. 371–386, 2009. @article{Moeller2009, Recent research suggests that developmental dyscalculia is associated with a subitizing deficit (i.e., the inability to quickly enumerate small sets of up to 3 objects). However, the nature of this deficit has not previously been investigated. In the present study the eye-tracking methodology was employed to clarify whether (a) the subitizing deficit of two boys with dyscalculia resulted from a general slowing in the access to magnitude representation, or (b) children with dyscalculia resort to a back-up counting strategy even for small object sets. In a dot-counting task, a standard problem size effect for the number of fixations required to encode the presented numerosity within the subitizing range was observed. Together with the finding that problem size had no impact on the average fixation duration, this result suggested that children with dyscalculia may indeed have to count, while typically developing controls are able to enumerate the number of dots in parallel, i.e., subitize. Implications for the understanding of developmental dyscalculia are considered. |
René M. Müri; D. Cazzoli; Thomas Nyffeler; Tobias Pflugshaupt Visual exploration pattern in hemineglect Journal Article In: Psychological Research, vol. 73, no. 2, pp. 147–157, 2009. @article{Mueri2009, The analysis of eye movement parameters in visual neglect such as cumulative fixation duration, saccade amplitude, or the numbers of saccades has been used to probe attention deficits in neglect patients, since the pattern of exploratory eye movements has been taken as a strong index of attention distribution. The current overview of the literature of visual neglect has its emphasis on studies dealing with eye movement and exploration analysis. We present our own results in 15 neglect patients. The free exploration behavior was analyzed in these patients presenting 32 naturalistic color photographs of everyday scenes. Cumulative fixation duration, spatial distribution of fixations in the horizontal and vertical plane, the number and amplitude of exploratory saccades was analyzed and compared with the results of an age-matched control group. A main result of our study was that in neglect patients, fixation distribution of free exploration of natural scenes is not only influenced by the left-right bias in the horizontal direction but also by the vertical direction. |
Menno Schoot; Annemieke H. Bakker Arkema; Tako M. Horsley; Ernest C. D. M. Lieshout In: Contemporary Educational Psychology, vol. 34, no. 1, pp. 58–66, 2009. @article{Schoot2009, This study examined the effects of consistency (relational term consistent vs. inconsistent with required arithmetic operation) and markedness (relational term unmarked ['more than'] vs. marked ['less than']) on word problem solving in 10-12 years old children differing in problem-solving skill. The results showed that for unmarked word problems, less successful problem solvers showed an effect of consistency on regressive eye movements (longer and more regressions to solution-relevant problem information for inconsistent than consistent word problems) but not on error rate. For marked word problems, they showed the opposite pattern (effects of consistency on error rate, not on regressive eye movements). The conclusion was drawn that, like more successful problem solvers, less successful problem solvers can appeal to a problem-model strategy, but that they do so only when the relational term is unmarked. The results were discussed mainly with respect to the linguistic-semantic aspects of word problem solving. |
Menno Schoot; Alain L. Vasbinder; Tako M. Horsley; Albert Reijntjes; Ernest C. D. M. Lieshout Lexical ambiguity resolution in good and poor comprehenders: An eye fixation and self-paced reading study in primary school children Journal Article In: Journal of Educational Psychology, vol. 101, no. 1, pp. 21–36, 2009. @article{Schoot2009a, To investigate the use of context and monitoring of comprehension in lexical ambiguity resolution in children, the authors asked 10- to 12-year-old good and poor comprehenders to read sentences consisting of 2 clauses, 1 containing the ambiguous word and the other the disambiguating information. The order of the clauses was reversed so that disambiguating information either preceded or followed the ambiguous word. Context use and comprehension monitoring were examined by measuring eye fixations (Experiment 1) and self-paced reading times (Experiment 2) on the ambiguous word and disambiguating region. The results of Experiment 1 and 2 showed that poor comprehenders made use of prior context to facilitate lexical ambiguity resolution as effectively as good comprehenders but that they monitored their comprehension less effectively than good comprehenders. Good comprehenders corrected an initial interpretation error on an ambiguous word and restored comprehension once they encountered the disambiguating region. Poor comprehenders failed to deal with this type of comprehension failure. |
Paul M. Brunet; Jennifer J. Heisz; Catherine J. Mondloch; David I. Shore; Louis A. Schmidt Shyness and face scanning in children Journal Article In: Journal of Anxiety Disorders, vol. 23, no. 7, pp. 909–914, 2009. @article{Brunet2009, Contrary to popular beliefs, a recent empirical study using eye tracking has shown that a non-clinical sample of socially anxious adults did not avoid the eyes during face scanning. Using eye-tracking measures, we sought to extend these findings by examining the relation between stable shyness and face scanning patterns in a non-clinical sample of 11-year-old children. We found that shyness was associated with longer dwell time to the eye region than the mouth, suggesting that some shy children were not avoiding the eyes. Shyness was also correlated with fewer first fixations to the nose, which is thought to reflect the typical global strategy of face processing. Present results replicate and extend recent work on social anxiety and face scanning in adults to shyness in children. These preliminary findings also provide support for the notion that some shy children may be hypersensitive to detecting social cues and intentions in others conveyed by the eyes. Theoretical and practical implications for understanding the social cognitive correlates and treatment of shyness are discussed. |
Karen L. Campbell; Naseem Al-Aidroos; Jay Pratt; Lynn Hasher Repelling the young and attracting the old: Examining age-related differences in saccade trajectory deviations Journal Article In: Psychology and Aging, vol. 24, no. 1, pp. 163–168, 2009. @article{Campbell2009a, In the present study, the authors examined age-related differences in saccade curvature as older and younger adults looked to an X target that appeared concurrently with an O distractor. They used a fixation gap procedure to introduce variance into the saccadic latencies of both groups. Consistent with earlier findings, younger adults' early onset saccades curved toward the distractor (as the distractor competed with the target for response selection), while late-onset saccades curved away from the distractor (as the distractor location became inhibited over time). In contrast, older adults' saccades gradually decreased in curvature toward the distractor, but at no point along the latency continuum did they show deviations away. These results suggest that while the local inhibitory mechanisms responsible for decreases in curvature toward distractors may be preserved with age, aging may lead to a selective decline in the frontal inhibitory mechanisms responsible for deviations away from distractors. |
Karen L. Campbell; Jennifer D. Ryan The effects of practice and external support on older adults' control of reflexive eye movements Journal Article In: Aging, Neuropsychology, and Cognition, vol. 16, no. 6, pp. 745–763, 2009. @article{Campbell2009, The present study examined whether external support and practice could reduce age differences in oculomotor control. Participants were to avoid fixating an abrupt onset and on some trials, were provided with a predictive cue regarding the onset location or identity. Older adults demonstrated more capture than younger adults, but both groups improved with practice. Whereas the older group benefited from a location preview (Experiment 1), neither group showed less capture when given a preview of the onset object itself (Experiment 2), suggesting that location-based inhibition, but not object-based inhibition, was sufficient to support oculomotor control within this paradigm. To test the generalizability of these skills, displays in a final block were manipulated such that the onset could appear in a different location or be a different object altogether. Viewing patterns were similar for changed vs. unchanged displays, suggesting that participants' practice-related gains could withstand a change in the task materials. |
Mary Ann Evans; Jean Saint-Aubin; Nadine Landry Letter names and alphabet book reading by senior kindergarteners: An eye movement study Journal Article In: Child Development, vol. 80, no. 6, pp. 1824–1841, 2009. @article{Evans2009a, The study monitored the eye movements of twenty 5-year-old children while reading an alphabet book to examine the manner in which the letters, words, and pictures were fixated and the relation of attention to print to alphabetic knowledge. Children attended little to the print, took longer to first fixate print than illustrations, and labeled fewer letters than when presented with letters in isolation. After controlling for receptive vocabulary, regressions revealed that children knowing more letters were quicker to look at the featured letter on a page and spent more time looking at the featured letter, the word, and its first letter. Thus, alphabet books along with letter knowledge may facilitate entrance into the partial alphabetic stage of word recognition. |
2008 |
Michael D. Crossland; Antony B. Morland; Mary P. Feely; Elisabeth Hagen; Gary S. Rubin The effect of age and fixation instability on retinotopic mapping of primary visual cortex Journal Article In: Investigative Ophthalmology & Visual Science, vol. 49, no. 8, pp. 3734–3739, 2008. @article{Crossland2008, PURPOSE: Functional magnetic resonance imaging (fMRI) experiments determining the retinotopic structure of visual cortex have commonly been performed on young adults, who are assumed to be able to maintain steady fixation throughout the trial duration. The authors quantified the effects of age and fixation stability on the quality of retinotopic maps of primary visual cortex. METHODS: With the use of a 3T fMRI scanner, the authors measured cortical activity in six older and six younger normally sighted participants observing an expanding flickering checkerboard stimulus of 30 degrees diameter. The area of flattened primary visual cortex (V1) showing any blood oxygen level-dependent (BOLD) activity to the visual stimulus and the area responding to the central 3.75 degrees of the stimulus (relating to the central ring of our target) were recorded. Fixation stability was measured while participants observed the same stimuli outside the scanner using an infrared gazetracker. RESULTS: There were no age-related changes in the area of V1. However, the proportion of V1 active to our visual stimulus was lower for the older observers than for the younger observers (overall activity: 89.8% of V1 area for older observers, 98.6% for younger observers; P <0.05). This effect was more pronounced for the central 3.75 degrees of the target (older subjects, 26.4%; younger subjects, 40.7%; P <0.02). No significant relationship existed between fixation stability and age or the magnitude of activity in the primary visual cortex. CONCLUSIONS: Although the cortical area remains unchanged, healthy older persons show less BOLD activity in V1 than do younger persons. Normal variations in fixation stability do not have a significant effect on the accuracy of experiments to determine the retinotopic structure of the visual cortex. |
Adele Diederich; Hans Colonius; Annette Schomburg Assessing age-related multisensory enhancement with the time-window-of-integration model Journal Article In: Neuropsychologia, vol. 46, no. 10, pp. 2556–2562, 2008. @article{Diederich2008b, Although from multisensory research a great deal is known about how the different senses interact, there is little knowledge as to the impact of aging on these multisensory processes. In this study, we measured saccadic reaction time (SRT) of aged and young individuals to the onset of a visual target stimulus with and without an accessory auditory stimulus occurring (focused attention task). The response time pattern for both groups was similar: mean SRT to bimodal stimuli was generally shorter than to unimodal stimuli, and mean bimodal SRT was shorter when the auditory accessory was presented ipsilaterally rather than contralaterally to the target. The elderly participants were considerably slower than the younger participants under all conditions but showed a greater multisensory enhancement, that is, they seem to benefit more from bimodal stimulus presentation. In an attempt to weigh the contributions of peripheral sensory processes relative to more central cognitive processes possibly responsible for the difference in the younger and older adults, the time-window-of-integration (TWIN) model for crossmodal interaction in saccadic eye movements developed by the authors was fitted to the data from both groups. The model parameters suggest that (i) there is a slowing of the peripheral sensory processing in the elderly, (ii) as a result of this slowing, the probability of integration is smaller in the elderly even with a wider time-window-of-integration, and (iii) multisensory integration, if it occurs, manifests itself in larger neural enhancement in the elderly; however, because of (ii), on average the integration effect is not large enough to compensate for the peripheral slowing in the elderly. |
Xu Huang; Jin Jing; Xiao-bing Zou; Meng-Long Wang; Xiu-Hong Li; Ai-Hua Lin Eye movements characteristics of Chinese dyslexic children in picture searching Journal Article In: Chinese Medical Journal, vol. 121, no. 17, pp. 1617–1621, 2008. @article{Huang2008, Background: Reading Chinese, a kind of ideogram, relies more on visual cognition. The visuospatial cognitive deficit of Chinese dyslexia is an interesting topic that has received much attention. The purpose of current research was to explore the visuopatial cognitive characteristics of Chinese dyslexic children by studying their eye movements via a picture searching test. Methods: According to the diagnostic criteria defined by ICD-10, twenty-eight dyslexic children (mean age (10.12±1.42) years) were enrolled from the Clinic of Children Behavioral Disorder in the third affiliated hospital of Sun Yat-sen University. And 28 normally reading children (mean age (10.06±1.29) years), 1:1 matched by age, sex, grade and family condition were chosen from an elementary school in Guangzhou as a control group. Four groups of pictures (cock, accident, canyon, meditate) from Picture Vocabulary Test were chosen as eye movement experiment targets. All the subjects carried out the picture searching task and their eye movement data were recorded by an Eyelink II High-Speed Eye Tracker. The duration time, average fixation duration, average saccade amplitude, fixation counts and saccade counts were compared between the two groups of children. Results: The dyslexic children had longer total fixation duration and average fixation duration (F=7.711, P <0.01; F=4.520, P <0.05), more fixation counts and saccade counts (F=7.498, P <0.01; F=11.040, P <0.01), and a smaller average saccade amplitude (F=29.743, P <0.01) compared with controls. But their performance in the picture vocabulary test was the same as those of the control group. The eye movement indexes were affected by the difficulty of the pictures and words, all eye movement indexes, except saccade amplitude, had a significant difference within groups (P <0.05). Conclusions: Chinese dyslexic children have abnormal eye movements in picture searching, applying slow fixations, more fixations and small and frequent saccades. Their abnormal eye movement mode reflects the poor ability and strategy of visual information processing. |
N. N. J. Rommelse; Stefan Van der Stigchel; J. Witlox; C. J. A. Geldof; J. -B. Deijen; Jan Theeuwes; Jaap Oosterlaan; J. A. Sergeant Deficits in visuo-spatial working memory, inhibition and oculomotor control in boys with ADHD and their non-affected brothers Journal Article In: Journal of Neural Transmission, vol. 115, no. 2, pp. 249–260, 2008. @article{Rommelse2008, Few studies have assessed visuo-spatial working memory and inhibition in attention-deficit/hyperactivity disorder (ADHD) by recording saccades and consequently little additional knowledge has been gathered on oculomotor functioning in ADHD. Moreover, this is the first study to report the performance of non-affected siblings of children with ADHD, which may shed light on the familiality of deficits. A total of 14 boys with ADHD, 18 non-affected brothers, and 15 control boys aged 7-14 years, were administered a memory-guided saccade task with delays of three and seven seconds. Familial deficits were found in accuracy of visuo-spatial working memory, percentage of anticipatory saccades, and tendency to overshoot saccades relative to controls. These findings suggest memory-guided saccade deficits may relate to a familial predisposition for ADHD. |
Laura Schmalzl; Romina Palermo; Melissa J. Green; Ruth Brunsdon; Max Coltheart Training of familiar face recognition and visual scan paths for faces in a child with congenital prosopagnosia Journal Article In: Cognitive Neuropsychology, vol. 25, no. 5, pp. 704–729, 2008. @article{Schmalzl2008, In the current report we describe a successful training study aimed at improving recognition ofa set of familiar face photographs in K., a 4-year-old girl with congenital prosopagnosia (CP). A detailed assessment of K.'s face-processing skills showed a deficit in structural encoding, most pronounced in the processing of facial features within the face. In addition, eye movement recordings revealed that K.'s scan paths for faces were characterized by a large percentage of fixations directed to areas outside the internal core features (i.e., eyes, nose, and mouth), in particular by poor attendance to the eye region. Following multiple baseline assessments, training focused on teaching K. to reliably recognize a set of familiar face photographs by directing visual attention to specific characteristics of the internal features of each face. The training significantly improved K.'s ability to recognize the target faces, with her performance being flawless immediately after training as well as at a follow-up assessment 1 month later. In addition, eye movement recordings following training showed a significant change in K.'s scan paths, with a significant increase in the percentage offixations directed to the internal features, particularly the eye region. Encouragingly, not only was the change in scan paths observed for the set offamiliar trained faces, but it generalized to a set offaces that was not presented during training. In addition to documenting significant training effects, our study raises the intriguing question ofwhether abnormal scan paths for faces may be a common factor underlying face recognition impairments in childhood CP, an issue that has not been explored so far. |
Michael Schneider; Angela Heine; Verena Thaler; Joke Torbeyns; Bert De Smedt; Lieven Verschaffel; Arthur M. Jacobs; Elsbeth Stern A validation of eye movements as a measure of elementary school children's developing number sense Journal Article In: Cognitive Development, vol. 23, no. 3, pp. 409–422, 2008. @article{Schneider2008, The number line estimation task captures central aspects of children's developing number sense, that is, their intuitions for numbers and their interrelations. Previous research used children's answer patterns and verbal reports as evidence of how they solve this task. In the present study we investigated to what extent eye movements recorded during task solution reflect children's use of the number line. By means of a cross-sectional design with 66 children from Grades 1, 2, and 3, we show that eye-tracking data (a) reflect grade-related increase in estimation competence, (b) are correlated with the accuracy of manual answers, (c) relate, in Grade 2, to children's addition competence, (d) are systematically distributed over the number line, and (e) replicate previous findings concerning children's use of counting strategies and orientation-point strategies. These findings demonstrate the validity and utility of eye-tracking data for investigating children's developing number sense and estimation competence. |
Linda Mortensen; Antje S. Meyer; Glyn W. Humphreys Speech planning during multiple-object naming: Effects of ageing Journal Article In: Quarterly Journal of Experimental Psychology, vol. 61, no. 8, pp. 1217–1238, 2008. @article{Mortensen2008, Two experiments were conducted with younger and older speakers. In Experiment 1, participants named single objects that were intact or visually degraded, while hearing distractor words that were phonologically related or unrelated to the object name. In both younger and older participants naming latencies were shorter for intact than for degraded objects and shorter when related than when unrelated distractors were presented. In Experiment 2, the single objects were replaced by object triplets, with the distractors being phonologically related to the first object's name. Naming latencies and gaze durations for the first object showed degradation and relatedness effects that were similar to those in single-object naming. Older participants were slower than younger participants when naming single objects and slower and less fluent on the second but not the first object when naming object triplets. The results of these experiments indicate that both younger and older speakers plan object names sequentially, but that older speakers use this planning strategy less efficiently. |
Ensar Becic; Walter R. Boot; Arthur F. Kramer Training older adults to search more effectively: Scanning strategy and visual search in dynamic displays Journal Article In: Psychology and Aging, vol. 23, no. 2, pp. 461–466, 2008. @article{Becic2008, The authors examined the ability of older adults to modify their search strategies to detect changes in dynamic displays. Older adults who made few eye movements during search (i.e., covert searchers) were faster and more accurate compared with individuals who made many eye movements (i.e., overt searchers). When overt searchers were instructed to adopt a covert search strategy, target detection performance increased to the level of natural covert searchers. Similarly, covert searchers instructed to search overtly exhibited a decrease in target detection performance. These data suggest that with instructions and minimal practice, older adults can ameliorate the cost of a poor search strategy. |
Menno Van Der Schoot; Alain L. Vasbinder; Tako M. Horsley; Ernest C. D. M. Van Lieshout The role of two reading strategies in text comprehension: An eye fixation study in primary school children Journal Article In: Journal of Research in Reading, vol. 31, no. 2, pp. 203–223, 2008. @article{VanDerSchoot2008, This study examined whether 1012-year-old children use two reading strategies to aid their text comprehension: (1) distinguishing between important and unimportant words; and (2) resolving anaphoric references. Of interest was the question to what extent use of these reading strategies was predictive of reading comprehension skill over and above decoding skill and vocabulary. Reading strategy use was examined by the recording of eye fixations on specific target words. In contrast to less successful comprehenders, more successful comprehenders invested more processing time in important than in unimportant words. On the other hand, they needed less time to determine the antecedent of an anaphor. The results suggest that more successful comprehenders build a more effective mental model of the text than less successful comprehenders in at least two ways. First, they allocate more attention to the incorporation of goal-relevant than goal-irrelevant information into the model. Second, they ascertain that the text model is coherent and richly connected. |
D. A. Mills; Teresa C. Frohman; Scott L. Davis; A. R. Salter; Samuel M. McClure; I. Beatty; A. Shah; S. Galetta; E. Eggenberger; D. S. Zee; Elliot M. Frohman Break in binocular fusion during head turning in MS patients with INO Journal Article In: Neurology, vol. 71, pp. 457–460, 2008. @article{Mills2008, Internuclear ophthalmoparesis (INO) is the most common eye movement abnormality observed in pa- tients with multiple sclerosis (MS).1 While most MS patients with INO have no or little misalignment in the straight ahead position, significant disconjugacy occurs during horizontal saccades or with horizontal (yaw axis) head turning.2 A break in binocular fusion can produce a loss of stereopsis and depth percep- tion, transient diplopia (perceived as a double image or visual blur), oscillopsia, and disorientation.2 The purpose of this investigation was to confirm the hy- pothesis that a break in binocular fusion occurs in MS patients with INO during head or body turning, and that the magnitude of disconjugacy will be di- rectly correlated with the severity of this eye move- ment syndrome. |
Inger Montfoort; Josef N. Geest; Harm P. Slijper; Chris I. Zeeuw; Maarten A. Frens Adaptation of the cervico- and vestibulo-ocular reflex in whiplash injury patients Journal Article In: Journal of Neurotrauma, vol. 25, pp. 687–693, 2008. @article{Montfoort2008, The aim of this study was to investigate the underlying mechanisms of the increased gains of the cervico-ocular reflex (COR) and the lack of synergy between the COR and the vestibulo-ocular reflex (VOR) that have been previously observed in patients with whiplash-associated disorders (WAD). Eye movements during COR or VOR stimulation were recorded in four different experiments. The effect of restricted neck motion and the relationship between muscle activity and COR gain was examined in healthy controls. The adaptive ability of the COR and the VOR was tested in WAD patients and healthy controls. Reduced neck mobility yielded an increase in COR gain. No correlation between COR gain and muscle activity was observed. Adaptation of both the COR and VOR was observed in healthy controls, but not in WAD patients. The increased COR gain of WAD patients may stem from a reduced neck mobility. The lack of adaptation of the two stabilization reflexes may result in a lack of synergy between them. These abnormalities may underlie several of the symptoms frequently observed in WAD, such as vertigo and dizziness. |
Larry Allen Abel; Zhong I. Wang; Louis F. Dell'Osso Wavelet analysis in infantile nystagmus syndrome: Limitations and abilities Journal Article In: Investigative Ophthalmology & Visual Science, vol. 49, no. 8, pp. 3413–3423, 2008. @article{Abel2008, PURPOSE: To investigate the proper usage of wavelet analysis in infantile nystagmus syndrome (INS) and determine its limitations and abilities. METHODS: Data were analyzed from accurate eye-movement recordings of INS patients. Wavelet analysis was performed to examine the foveation characteristics, morphologic characteristics and time variation in different INS waveforms. Also compared were the wavelet analysis and the expanded nystagmus acuity function (NAFX) analysis on sections of pre- and post-tenotomy data. RESULTS: Wavelet spectra showed some sensitivity to different features of INS waveforms and reflected their variations across time. However, wavelet analysis was not effective in detecting foveation periods, especially in a complicated INS waveform. NAFX, on the other hand, was a much more direct way of evaluating waveform changes after nystagmus treatments. CONCLUSIONS: Wavelet analysis is a tool that performs, with difficulty, some things that can be done faster and better by directly operating on the nystagmus waveform itself. It appears, however, to be insensitive to the subtle but visually important improvements brought about by INS therapies. Wavelet analysis may have a role in developing automated waveform classifiers where its time-dependent characterization of the waveform can be used. The limitations of wavelet analysis outweighed its abilities in INS waveform-characteristic examination. |
Shery Thomas; Frank A. Proudlock; Nagini Sarvananthan; Eryl O. Roberts; Musarat Awan; Rebecca J. McLean; Mylvaganam Surendran; A. S. Anil Kumar; Shegufta J. Farooq; Christopher Degg; Richard P. Gale; Robert D. Reinecke; Geoffrey Woodruff; Andrea Langmann; Susanne Lindner; Sunila Jain; Patrick Tarpey; F. Lucy Raymond; Irene Gottlob Phenotypical characteristics of idiopathic infantile nystagmus with and without mutations in FRMD7 Journal Article In: Brain, vol. 131, no. 5, pp. 1259–1267, 2008. @article{Thomas2008, Idiopathic infantile nystagmus (IIN) consists of involuntary oscillations of the eyes. The familial form is most commonly X-linked. We recently found mutations in a novel gene FRMD7 (Xq26.2), which provided an opportunity to investigate a genetically defined and homogeneous group of patients with nystagmus. We compared clinical features and eye movement recordings of 90 subjects with mutation in the gene (FRMD7 group) to 48 subjects without mutations but with clinical IIN (non-FRMD7 group). Fifty-eight female obligate carriers of the mutation were also investigated. The median visual acuity (VA) was 0.2 logMAR (Snellen equivalent 6/9) in both groups and most patients had good stereopsis. The prevalence of strabismus was also similar (FRMD7: 7.8%, non-FRMD7: 10%). The presence of anomalous head posture (AHP) was significantly higher in the non-FRMD7 group (P < 0.0001). The amplitude of nystagmus was more strongly dependent on the direction of gaze in the FRMD7 group being lower at primary position (P < 0.0001), compared to non-FRMD7 group (P = 0.83). Pendular nystagmus waveforms were also more frequent in the FRMD7 group (P = 0.003). Fifty-three percent of the obligate female carriers of an FRMD7 mutation were clinically affected. The VA's in affected females were slightly better compared to affected males (P = 0.014). Subnormal optokinetic responses were found in a subgroup of obligate unaffected carriers, which may be interpreted as a sub-clinical manifestation. FRMD7 is a major cause of X-linked IIN. Most clinical and eye movement characteristics were similar in the FRMD7 group and non-FRMD7 group with most patients having good VA and stereopsis and low incidence of strabismus. Fewer patients in the FRMD7 group had AHPs, their amplitude of nystagmus being lower in primary position. Our findings are helpful in the clinical identification of IIN and genetic counselling of nystagmus patients. |
Stefan Van der Stigchel; Wieske Zoest; Jan Theeuwes; Jason J. S. Barton The influence of "blind" distractors on eye movement trajectories in visual hemifield defects Journal Article In: Journal of Cognitive Neuroscience, vol. 20, no. 11, pp. 2025–2036, 2008. @article{VanderStigchel2008a, There is evidence that some visual information in blind regions may still be processed in patients with hemifield defects after cerebral lesions ("blindsight"). We tested the hypothesis that, in the absence of retinogeniculostriate processing, residual retinotectal processing may still be detected as modifications of saccades to seen targets by irrelevant distractors in the blind hemifield. Six patients were presented with distractors in the blind and intact portions of their visual field and participants were instructed to make eye movements to targets in the intact field. Eye movements were recorded to determine if blind-field distractors caused deviation in saccadic trajectories. No deviation was found in one patient with an optic chiasm lesion, which affect both retinotectal and retinogeniculostriate pathways. In five patients with lesions of the optic radiations or the striate cortex, the results were mixed, with two of the five patients showing significant deviations of saccadic trajectory away from the "blind" distractor. In a second experiment, two of the five patients were tested with the target and the distractor more closely aligned. Both patients showed a "global effect," in that saccades deviated toward the distractor, but the effect was stronger in the patient who also showed significant trajectory deviation in the first experiment. Although our study confirms that distractor effects on saccadic trajectory can occur in patients with damage to the retinogeniculostriate visual pathway but preserved retinotectal projections, there remain questions regarding what additional factors are required for these effects to manifest themselves in a given patient. |
Z. I. Wang; Louis F. Dell'Osso Tenotomy procedure alleviates the "slow to see" phenomenon in infantile nystagmus syndrome: Model prediction and patient data Journal Article In: Vision Research, vol. 48, no. 12, pp. 1409–1419, 2008. @article{Wang2008, Our purpose was to perform a systematic study of the post-four-muscle-tenotomy procedure changes in target acquisition time by comparing predictions from the behavioral ocular motor system (OMS) model and data from infantile nystagmus syndrome (INS) patients. We studied five INS patients who underwent only tenotomy at the enthesis and reattachment at the original insertion of each (previously unoperated) horizontal rectus muscle for their INS treatment. We measured their pre- and post-tenotomy target acquisition changes using data from infrared reflection and high-speed digital video. Three key aspects were calculated and analyzed: the saccadic latency (Ls), the time to target acquisition after the target jump (Lt) and the normalized stimulus time within the cycle. Analyses were performed in MATLAB environment (The MathWorks, Natick, MA) using OMLAB software (OMtools, available from http://www.omlab.org). Model simulations were performed in MATLAB Simulink environment. The model simulation suggested an Lt reduction due to an overall foveation-quality improvement. Consistent with that prediction, improvement in Lt, ranging from ∼200 ms to ∼500 ms (average ∼ 280 ms), was documented in all five patients post-tenotomy. The Lt improvement was not a result of a reduced Ls. INS patients acquired step-target stimuli faster post-tenotomy. This target acquisition improvement may be due to the elevated foveation quality resulting in less inherent variation in the input to the OMS. A refined behavioral OMS model, with "fast" and "slow" motor neuron pathways and a more physiological plant, successfully predicted this improved visual behavior and again demonstrated its utility in guiding ocular motor research. |
Sarah Bate; Catherine Haslam; Jeremy J. Tree; Timothy L. Hodgson Evidence of an eye movement-based memory effect in congenital prosopagnosia Journal Article In: Cortex, vol. 44, no. 7, pp. 806–819, 2008. @article{Bate2008, While extensive work has examined the role of covert recognition in acquired prosopagnosia, little attention has been directed to this process in the congenital form of the disorder. Indeed, evidence of covert recognition has only been demonstrated in one congenital case in which autonomic measures provided evidence of recognition (Jones and Tranel, 2001), whereas two investigations using behavioural indicators failed to demonstrate the effect (de Haan and Campbell, 1991; Bentin et al., 1999). In this paper, we use a behavioural indicator, an "eye movement-based memory effect" (Althoff and Cohen, 1999), to provide evidence of covert recognition in congenital prosopagnosia. In an initial experiment, we examined viewing strategies elicited to famous and novel faces in control participants, and found fewer fixations and reduced regional sampling for famous compared to novel faces. In a second experiment, we examined the same processes in a patient with congenital prosopagnosia (AA), and found some evidence of an eye movement-based memory effect regardless of his recognition accuracy. Finally, we examined whether a difference in scanning strategy was evident for those famous faces AA failed to explicitly recognise, and again found evidence of reduced sampling for famous faces. We use these findings to (a) provide evidence of intact structural representations in a case of congenital prosopagnosia, and (b) to suggest that covert recognition can be demonstrated using behavioural indicators in this disorder. |
Valérie Gaveau; Denis Pélisson; Annabelle Blangero; Christian Urquizar; Claude Prablanc; Alain Vighetto; Laure Pisella Saccade control and eye-hand coordination in optic ataxia Journal Article In: Neuropsychologia, vol. 46, no. 2, pp. 475–486, 2008. @article{Gaveau2008, The aim of this work was to investigate ocular control in patients with optic ataxia (OA). Following a lesion in the posterior parietal cortex (PPC), these patients exhibit a deficit for fast visuo-motor control of reach-to-grasp movements. Here, we assessed the fast visuo-motor control of saccades as well as spontaneous eye-hand coordination in two bilateral OA patients and five neurologically intact controls in an ecological "look and point" paradigm. To test fast saccadic control, trials with unexpected target-jumps synchronised with saccade onset were randomly intermixed with stationary target trials. Results confirmed that control subjects achieved visual capture (foveation) of the displaced targets with the same timing as stationary targets (fast saccadic control) and began their hand movement systematically at the end of the primary saccade. In contrast, the two bilateral OA patients exhibited a delayed visual capture, especially of displaced targets, resulting from an impairment of fast saccadic control. They also exhibited a peculiar eye-hand coordination pattern, spontaneously delaying their hand movement onset until the execution of a final corrective saccade, which allowed target foveation. To test whether this pathological behaviour results from a delay in updating visual target location, we had subjects perform a second experiment in the same control subjects in which the target-jump was synchronised with saccade offset. With less time for target location updating, the control subjects exhibited the same lack of fast saccadic control as the OA patients. We propose that OA corresponds to an impairment of fast updating of target location, therefore affecting both eye and hand movements. |
Melissa J. Green; Jennifer H. Waldron; Ian Simpson; Max Coltheart Visual processing of social context during mental state perception in schizophrenia Journal Article In: Journal of Psychiatry and Neuroscience, vol. 33, no. 1, pp. 34–42, 2008. @article{Green2008, OBJECTIVE: To examine schizophrenia patients' visual attention to social contextual information during a novel mental state perception task. METHOD: Groups of healthy participants (n = 26) and schizophrenia patients (n = 24) viewed 7 image pairs depicting target characters presented context-free and context-embedded (i.e., within an emotion-congruent social context). Gaze position was recorded with the EyeLink I Gaze Tracker while participants performed a mental state inference task. Mean eye movement variables were calculated for each image series (context-embedded v. context-free) to examine group differences in social context processing. RESULTS: The schizophrenia patients demonstrated significantly fewer saccadic eye movements when viewing context-free images and significantly longer eye-fixation durations when viewing context-embedded images. Healthy individuals significantly shortened eye-fixation durations when viewing context-embedded images, compared with context-free images, to enable rapid scanning and uptake of social contextual information; however, this pattern of visual attention was not pronounced in schizophrenia patients. In association with limited scanning and reduced visual attention to contextual information, schizophrenia patients' assessment of the mental state of characters embedded in social contexts was less accurate. CONCLUSION: In people with schizophrenia, inefficient integration of social contextual information in real-world situations may negatively affect the ability to infer mental and emotional states from facial expressions. |
Tobias Pflugshaupt; Thomas Nyffeler; Roman Von Wartburg; Christian W. Hess; René M. Müri Loss of exploratory vertical saccades after unilateral frontal eye field damage Journal Article In: Journal of Neurology, Neurosurgery and Psychiatry, vol. 79, no. 4, pp. 474–477, 2008. @article{Pflugshaupt2008, Despite their relevance for locomotion and social interaction in everyday situations, little is known about the cortical control of vertical saccades in humans. Results from microstimulation studies indicate that both frontal eye fields (FEFs) contribute to these eye movements. Here, we present a patient with a damaged right FEF, who hardly made vertical saccades during visual exploration. This finding suggests that, for the cortical control of exploratory vertical saccades, integrity of both FEFs is indeed important. |
Teresa D. Hernandez; Carmel A. Levitan; Martin S. Banks; Clifton M. Schor How does saccade adaptation affect visual perception? Journal Article In: Journal of Vision, vol. 8, no. 8, pp. 1–16, 2008. @article{Hernandez2008, Three signals are used to visually localize targets and stimulate saccades: (1) retinal location signals for intended saccade amplitude, (2) sensory-motor transform (SMT) of retinal signals to extra-ocular muscle innervation, and (3) estimates of eye position from extra-retinal signals. We investigated effects of adapting saccade amplitude to a double-step change in target location on perceived direction. In a flashed-pointing task, subjects pointed an unseen hand at a briefly displayed eccentric target without making a saccade. In a sustained-pointing task, subjects made a horizontal saccade to a double-step target. One second after the second step, they pointed an unseen hand at the final target position. After saccade-shortening adaptation, there was little change in hand-pointing azimuth toward the flashed target suggesting that most saccade adaptation was caused by changes in the SMT. After saccade-lengthening adaptation, there were small changes in hand-pointing azimuth to flashed targets, indicating that 1/3 of saccade adaptation was caused by changes in estimated retinal location signals and 2/3 by changes in the SMT. The sustained hand-pointing task indicated that estimates of eye position adapted inversely with changes of the SMT. Changes in perceived direction resulting from saccade adaptation are mainly influenced by extra-retinal factors with a small retinal component in the lengthening condition. |
Alexandra Soliman; Gillian A. O'Driscoll; Jens Pruessner; Anne Lise V. Holahan; Isabelle Boileau; Danny Gagnon; Alain Dagher Stress-induced dopamine release in humans at risk of psychosis: A [ "C] raclopride PET study Journal Article In: Neuropsychopharmacology, vol. 33, no. 8, pp. 2033–2041, 2008. @article{Soliman2008, Drugs that increase dopamine levels in the brain can cause psychotic symptoms in healthy individuals and worsen them in schizophrenic patients. Psychological stress also increases dopamine release and is thought to play a role in susceptibility to psychotic illness. We hypothesized that healthy individuals at elevated risk of developing psychosis would show greater striatal dopamine release than controls in response to stress. Using positron emission tomography and [(11)C]raclopride, we measured changes in synaptic dopamine concentrations in 10 controls and 16 psychometric schizotypes; 9 with perceptual aberrations (PerAb, ie positive schizotypy) and 7 with physical anhedonia (PhysAn, ie negative schizotypy). [(11)C]Raclopride binding potential was measured during a psychological stress task and a sensory-motor control. All three groups showed significant increases in self-reported stress and cortisol levels between the stress and control conditions. However, only the PhysAn group showed significant stress-induced dopamine release. Dopamine release in the entire sample was significantly negatively correlated with smooth pursuit gain, an endophenotype linked to frontal lobe function. Our findings suggest the presence of abnormalities in the dopamine response to stress in negative symptom schizotypy, and provide indirect evidence of a link to frontal function. |
Giovanni Taibbi; Zhong I. Wang; Louis F. Dell'Osso Infantile nystagmus syndrome : Broadening the high-foveation-quality fi eld with contact lenses Journal Article In: Ophthalmology, vol. 2, no. 3, pp. 585–589, 2008. @article{Taibbi2008, We investigated the effects of contact lenses in broadening and improving the high-foveation-quality fi eld in a subject with infantile nystagmus syndrome (INS). A high-speed, digitized video system was used for the eye-movement recording. The subject was asked to fi xate a far target at different horizontal gaze angles with contact lenses inserted. Data from the subject while fi xating at far without refractive correction and at near (at a convergence angle of 60 PD), were used for comparison. The eXpanded Nystagmus Acuity Function (NAFX) was used to evaluate the foveation quality at each gaze angle. Contact lenses broadened the high- foveation-quality range of gaze angles in this subject. The broadening was comparable to that achieved during 60 PD of convergence although the NAFX values were lower. Contact lenses allowed the subject to see “more” (he had a wider range of high-foveation-quality gaze angles) and “better” (he had improved foveation at each gaze angle). Instead of being contraindicated by INS, contact lenses emerge as a potentially important therapeutic option. Contact lenses employ afferent feedback via the ophthalmic division of the V cranial nerve to damp INS slow phases over a broadened range of gaze angles. This supports the proprioceptive hypothesis of INS improvement. |
Manon W. Jones; Mateo Obregón; M. Louise Kelly; Holly P. Branigan Elucidating the component processes involved in dyslexic and non-dyslexic reading fluency: An eye-tracking study Journal Article In: Cognition, vol. 109, no. 3, pp. 389–407, 2008. @article{Jones2008, The relationship between rapid automatized naming (RAN) and reading fluency is well documented (see Wolf, M. & Bowers, P.G. (1999). The double-deficit hypothesis for the developmental dyslexias. Journal of Educational Psychology, 91(3), 415-438, for a review), but little is known about which component processes are important in RAN, and why developmental dyslexics show longer latencies on these tasks. Researchers disagree as to whether these delays are caused by impaired phonological processing or whether extra-phonological processes also play a role (e.g., Clarke, P., Hulme, C., & Snowling, M. (2005). Individual differences in RAN and reading: A response timing analysis. Journal of Research in Reading, 28(2), 73-86; Wolf, M., Bowers, P.G., & Biddle, K. (2000). Naming-speed processes, timing, and reading: A conceptual review. Journal of learning disabilities, 33(4), 387-407). We conducted an eye-tracking study that manipulated phonological and visual information (as representative of extra-phonological processes) in RAN. Results from linear mixed (LME) effects analyses showed that both phonological and visual processes influence naming-speed for both dyslexic and non-dyslexic groups, but the influence on dyslexic readers is greater. Moreover, dyslexic readers' difficulties in these domains primarily emerge in a measure that explicitly includes the production phase of naming. This study elucidates processes underpinning RAN performance in non-dyslexic readers and pinpoints areas of difficulty for dyslexic readers. We discuss these findings with reference to phonological and extra-phonological hypotheses of naming-speed deficits. |
Chantal Kemner; Lizet Ewijk; Herman Engeland; Ignace T. C. Hooge Brief report: Eye movements during visual search tasks indicate enhanced stimulus discriminability in subjects with PDD Journal Article In: Journal of Autism and Developmental Disorders, vol. 38, no. 3, pp. 553–558, 2008. @article{Kemner2008, Subjects with PDD excel on certain visuo-spatial tasks, amongst which visual search tasks, and this has been attributed to enhanced perceptual discrimination. However, an alternative explanation is that subjects with PDD show a different, more effective search strategy. The present study aimed to test both hypotheses, by measuring eye movements during visual search tasks in high functioning adult men with PDD and a control group. Subjects with PDD were significantly faster than controls in these tasks, replicating earlier findings in children. Eye movement data showed that subjects with PDD made fewer eye movements than controls. No evidence was found for a different search strategy between the groups. The data indicate an enhanced ability to discriminate between stimulus elements in PDD. |
Stefan Klöppel; Bogdan Draganski; Charlotte V. Golding; Carlton Chu; Zoltan Nagy; Philip A. Cook; Stephen L. Hicks; Christopher Kennard; Daniel C. Alexander; Geoff J. M. Parker; Sarah J. Tabrizi; Richard S. J. Frackowiak White matter connections reflect changes in voluntary-guided saccades in pre-symptomatic Huntington's disease Journal Article In: Brain, vol. 131, no. 1, pp. 196–204, 2008. @article{Kloeppel2008, Huntington's disease is caused by a known genetic mutation and so potentially can be diagnosed many years before the onset of symptoms. Neuropathological changes have been found in both striatum and frontal cortex in the pre-symptomatic stage. Disruption of cortico-striatal white matter fibre tracts is therefore likely to contribute to the first clinical signs of the disease. We analysed diffusion tensor MR image (DTI) data from 25 pre-symptomatic gene carriers (PSCs) and 20 matched controls using a multivariate support vector machine to identify patterns of changes in fractional anisotropy (FA). In addition, we performed probabilistic fibre tracking to detect changes in 'streamlines' connecting frontal cortex to striatum. We found a pattern of structural brain changes that includes putamen bilaterally as well as anterior parts of the corpus callosum. This pattern was sufficiently specific to enable us to correctly classify 82% of scans as coming from a PSC or control subject. Fibre tracking revealed a reduction of frontal cortico-fugal streamlines reaching the body of the caudate in PSCs compared to controls. In the left hemispheres of PSCs we found a negative correlation between years to estimated disease onset and streamlines from frontal cortex to body of caudate. A large proportion of the fibres to the caudate body originate from the frontal eye fields, which play an important role in the control of voluntary saccades. This type of saccade is specifically impaired in PSCs and is an early clinical sign of motor abnormalities. A correlation analysis in 14 PSCs revealed that subjects with greater impairment of voluntary-guided saccades had fewer fibre tracking streamlines connecting the frontal cortex and caudate body. Our findings suggest a specific patho-physiological basis for these symptoms by indicating selective vulnerability of the associated white matter tracts. |
Scott L. Davis; Teresa C. Frohman; C. J. Crandall; M. J. Brown; D. A. Mills; Phillip D. Kramer; O. Stuve; Elliot M. Frohman Modeling Uhthoff's phenomenon in MS patients with internuclear ophthalmoparesis Journal Article In: Neurology, vol. 70, pp. 1098–1106, 2008. @article{Davis2008, Objective: The goal of this investigation was to demonstrate that internuclear ophthalmoparesis (INO) can be utilized to model the effects of body temperature-induced changes on the fidelity of axonal conduction in multiple sclerosis (Uhthoff's phenomenon). Methods: Ocular motor function was measured using infrared oculography at 10-minute intervals in patients with multiple sclerosis (MS) with INO (MS-INO; n=8), patients with MS without INO (MS-CON; n=8), and matched healthy controls (CON; n=8) at normothermic baseline, during whole-body heating (increase in core temperature 0.8°C as measured by an ingestible temperature probe and transabdominal telemetry), and after whole-body cooling. The versional disconjugacy index (velocity-VDI), the ratio of abducting/adducting eye movements for velocity, was calculated to assess changes in interocular disconjugacy. The first pass amplitude (FPA), the position of the adducting eye when the abducting eye achieves a centrifugal fixation target, was also computed. Results: Velocity-VDI and FPA in MS-INO patients was elevated (p<0.001) following whole body heating with respect to baseline measures, confirming a compromise in axonal electrical impulse transmission properties. Velocity-VDI and FPA in MS-INO patients was then restored to baseline values following whole-body cooling, confirming the reversible and stereotyped nature of this characteristic feature of demyelination. Conclusions: We have developed a neurophysiologic model for objectively understanding temperature-related reversible changes in axonal conduction in multiple sclerosis. Our observations corroborate the hypothesis that changes in core body temperature (heating and cooling) are associated with stereotypic decay and restoration in axonal conduction mechanisms. |
Elmar H. Pinkhardt; Reinhart Jürgens; Wolfgang Becker; Federica Valdarno; Albert C. Ludolph; Jan Kassubek Differential diagnostic value of eye movement recording in PSP-parkinsonism, Richardson's syndrome, and idiopathic Parkinson's disease Journal Article In: Journal of Neurology, vol. 255, no. 12, pp. 1916–1925, 2008. @article{Pinkhardt2008, Vertical gaze palsy is a highly relevant clinical sign in parkinsonian syndromes. As the eponymous sign of progressive supranuclear palsy (PSP), it is one of the core features in the diagnosis of this disease. Recent studies have suggested a further differentiation of PSP in Richardson's syndrome (RS) and PSP-parkinsonism (PSPP). The aim of this study was to search for oculomotor abnormalities in the PSP-P subset of a sample of PSP patients and to compare these findings with those of (i) RS patients, (ii) patients with idiopathic Parkinson's disease (IPD), and (iii) a control group. Twelve cases of RS, 5 cases of PSP-P, and 27 cases of IPD were examined by use of video-oculography (VOG) and compared to 23 healthy normal controls. Both groups of PSP patients (RS, PSP-P) had significantly slower saccades than either IPD patients or controls, whereas no differences in saccadic eye peak velocity were found between the two PSP groups or in the comparison of IPD with controls. RS and PSP-P were also similar to each other with regard to smooth pursuit eye movements (SPEM), with both groups having significantly lower gain than controls (except for downward pursuit); however, SPEM gain exhibited no consistent difference between PSP and IPD. A correlation between eye movement data and clinical data (Hoehn & Yahr scale or disease duration) could not be observed. As PSP-P patients were still in an early stage of the disease when a differentiation from IPD is difficult on clinical grounds, the clear-cut separation between PSP-P and IPD obtained by measuring saccade velocity suggests that VOG could contribute to the early differentiation between these patient groups. |
Archana Pradeep; Shery Thomas; Eryl O. Roberts; Frank A. Proudlock; Irene Gottlob Reduction of congenital nystagmus in a patient after smoking cannabis Journal Article In: Strabismus, vol. 16, no. 1, pp. 29–32, 2008. @article{Pradeep2008, INTRODUCTION: Smoking cannabis has been described to reduce acquired pendular nystagmus in MS, but its effect on congenital nystagmus is not known. PURPOSE: To report the effect of smoking cannabis in a case of congenital nystagmus. METHODS: A 19-year-old male with congenital horizontal nystagmus presented to the clinic after smoking 10 mg of cannabis. He claimed that the main reason for smoking cannabis was to improve his vision. At the next clinic appointment, he had not smoked cannabis for 3weeks. Full ophthalmologic examination and eye movement recordings were performed at each visit. RESULTS: Visual acuity improved by 3 logMar lines in the left eye and by 2 logMar lines in the right eye after smoking cannabis. The nystagmus intensities were reduced by 30% in primary position and 44%, 11%, 10% and 40% at 20-degree eccentricity to the right, left, elevation and depression, respectively, after smoking cannabis. CONCLUSION: Cannabis may be beneficial in the treatment of congenital idiopathic nystagmus (CIN). Further research to clarify the safety and efficacy of cannabis in patients with CIN, administered for example by capsules or spray, would be important. |
Tamara A. Russell; Melissa J. Green; Ian Simpson; Max Coltheart Remediation of facial emotion perception in schizophrenia: Concomitant changes in visual attention Journal Article In: Schizophrenia Research, vol. 103, no. 1-3, pp. 248–256, 2008. @article{Russell2008, The study examined changes in visual attention in schizophrenia following training with a social-cognitive remediation package designed to improve facial emotion recognition (the Micro-Expression Training Tool; METT). Forty out-patients with schizophrenia were randomly allocated to active training (METT; n = 26), or repeated exposure (RE; n = 14); all completed an emotion recognition task with concurrent eye movement recording. Emotion recognition accuracy was significantly improved in the METT group, and this effect was maintained after one week. Immediately following training, the METT group directed more eye movements within feature areas of faces (i.e., eyes, nose, mouth) compared to the RE group. The number of fixations directed to feature areas of faces was positively associated with emotion recognition accuracy prior to training. After one week, the differences between METT and RE groups in viewing feature areas of faces were reduced to trends. However, within group analyses of the METT group revealed significantly increased number of fixations to, and dwell time within, feature areas following training which were maintained after one week. These results provide the first evidence that improvements in emotion recognition following METT training are associated with changes in visual attention to the feature areas of emotional faces. These findings support the contribution of visual attention abnormalities to emotion recognition impairment in schizophrenia, and suggest that one mechanism for improving emotion recognition involves re-directing visual attention to relevant features of emotional faces. |
Paul Sauleau; Pierre Pollak; Paul Krack; Jean Hubert Courjon; Alain Vighetto; Alim Louis Benabid; Denis Pélisson; Caroline Tilikete Subthalamic stimulation improves orienting gaze movements in Parkinson's disease Journal Article In: Clinical Neurophysiology, vol. 119, no. 8, pp. 1857–1863, 2008. @article{Sauleau2008, Objective: To determine the effect of subthalamic stimulation on visually triggered eye and head movements in patients with Parkinson's disease (PD). Methods: We compared the gain and latency of visually triggered eye and head movements in 12 patients bilaterally implanted into the subthalamic nucleus (STN) for severe PD and six age-matched control subjects. Visually triggered movements of eye (head restrained), and of eye and head (head unrestrained) were recorded in the absence of dopaminergic medication. Bilateral stimulation was turned OFF and then turned ON with voltage and contact used in chronic setting. The latency was determined from the beginning of initial horizontal eye movements relative to the target onset, and the gain was defined as the ratio of the amplitude of the initial movement to the amplitude of the target movement. Results: Without stimulation, the initiation of the head movement was significantly delayed in patients and the gain of head movement was reduced. Our patients also presented significantly prolonged latencies and hypometry of visually triggered saccades in the head-fixed condition and of gaze in head-free condition. Bilateral STN stimulation with therapeutic parameters improved performance of orienting gaze, eye and head movements towards the controls' level. Conclusions: These results demonstrate that visually triggered saccades and orienting eye-head movements are impaired in the advanced stage of PD. In addition, subthalamic stimulation enhances amplitude and shortens latency of these movements. Significance: These results are likely explained by alteration of the information processed by the superior colliculus (SC), a pivotal visuomotor structure involved in both voluntary and reflexive saccades. Improvement of movements with stimulation of the STN may be related to its positive input either on the STN-Substantia Nigra-SC pathway or on the parietal cortex-SC pathway. |
2007 |
Christoph Helmchen; Stefan Gottschalk; Thurid Sander; Peter Trillenberg; Holger Rambold; Andreas Sprenger Beneficial effects of 3,4-diaminopyridine on positioning downbeat nystagmus in a circumscribed uvulo-nodular lesion [6] Journal Article In: Journal of Neurology, vol. 254, no. 8, pp. 1126–1128, 2007. @article{Helmchen2007, Central positioning downbeat nystagmus (pDBN) presents with transient nystagmus in supine or the head hanging position in the absence of DBN in the head erect position. In contrast to central positional downbeat nystagmus, pDBN requires rapid head posi- tioning manoeuvres to be elicited. The pathomechanism and therapy of central pDBN is not yet known and circumscribed lesions are missing so far [1, 2]. We examined the effect of 3,4-diaminopyridine (DAP) [3, 4] on the oculomotor behavior of a patient with pDBN. |
Timothy L. Hodgson; Marcia Chamberlain; Benjamin A. Parris; Martin James; Nicholas Gutowski; Masud Husain; Christopher Kennard The role of the ventrolateral frontal cortex in inhibitory oculomotor control Journal Article In: Brain, vol. 130, no. 6, pp. 1525–1537, 2007. @article{Hodgson2007, It has been proposed that the inferior/ventrolateral frontal cortex plays a critical role in the inhibitory control of action during cognitive tasks. However, the contribution of this region to the control of eye movements has not been clearly established. Here, we describe the performance of a group of 23 frontal lobe damaged patients in an oculomotor rule switching task for which the association between a centrally presented visual cue and the direction of a saccade could change from trial to trial. A subset of 16 patients also completed the standard antisaccade task. Ventrolateral damage was found to be a significant predictor of errors in both tasks. Analysis of the rate at which patients corrected errors in the rule switching task also revealed an important dissociation between left and right hemisphere damaged patients. Whilst patients with left ventrolateral damage usually corrected response errors with secondary saccades, those with right hemisphere lesions often failed to do so. The results suggest that the inferior frontal cortex forms part of a wider frontal network mediating inhibitory control over stimulus elicited eye movements. The critical role played by the right ventrolateral region in cognitive tasks may arise due to an additional functional specialization for the monitoring and updating of task rules. |
J. Hübner; Andreas Sprenger; C. Klein; J. Hagenah; Holger Rambold; C. Zuhlke; D. Kompf; A. Rolfs; H. Kimmig; Christoph Helmchen Eye movement abnormalities in spinocerebellar ataxia type 17 (SCA17) Journal Article In: Neurology, vol. 69, no. 11, pp. 1160–1168, 2007. @article{Huebner2007, BACKGROUND: Spinocerebellar ataxia type 17 (SCA17) is associated with an expansion of CAG/CAA trinucleotide repeats in the gene encoding the TATA-binding protein. In this quantitative characterization of eye movements in SCA17 mutation carriers, we investigated whether eye movement abnormalities originate from multiple lesion sites as suggested by their phenotypic heterogeneity. METHODS: Eye movements (saccades, smooth pursuit) of 15 SCA17 mutation carriers (mean age 36.9 years, range 20 to 54 years; mean disease duration 7.3 years, range 0 to 20 years; 2 clinically unaffected, 13 affected) were compared with 15 age-matched control subjects using the video-based two-dimensional EYELINK II system. RESULTS: Smooth pursuit initiation (step-ramp paradigm) and maintenance were strongly impaired, i.e., pursuit latency was increased and acceleration decreased, whereas latency and position error of the first catch-up saccade were normal. Visually guided saccades were hypometric but had normal velocities. Gaze-evoked nystagmus was found in one-third of the mutation carriers, including downbeat and rebound nystagmus. There was a pathologic increase in error rates of antisaccades (52%) and memory-guided saccades (42%). Oculomotor disorders were not correlated with repeat length. Smooth pursuit impairment and saccadic disorders increased with disease duration. CONCLUSIONS: Several oculomotor deficits of spinocerebellar ataxia type 17 (SCA17) mutation carriers are compatible with cerebellar degeneration. This is consistent with histopathologic and imaging (morphometric) data. In contrast, increased error rates in antisaccades and memory-guided saccades point to a deficient frontal inhibition of reflexive movements, which is probably best explained by cortical dysfunction and may be related to other phenotypic SCA17 signs, e.g., dementia and parkinsonism. |
Vyv C. Huddy; Timothy L. Hodgson; Masuma Kapasi; Stanley H. Mutsatsa; Isobel Harrison; Thomas R. E. Barnes; Eileen M. Joyce Gaze strategies during planning in first-episode psychosis Journal Article In: Journal of Abnormal Psychology, vol. 116, no. 3, pp. 589–598, 2007. @article{Huddy2007, Eye movements were measured during the performance of a computerized Tower of London task to specify the source of planning abnormalities in patients with 1st-episode schizophrenia or schizoaffective disorder. Subjects viewed 2 arrays of colored balls in the upper and lower parts of the screen. They were asked to plan the shortest sequence of moves required to rearrange the balls in the lower screen to match the upper arrangement. Compared with healthy controls, patients made more planning errors, and decision times were longer. However, the patients showed the same gaze biases as controls prior to making a response, indicating that they understood the requirements of the task, approached the task in a strategic manner by identifying the nature of the problem, and used appropriate fixation strategies to plan and elaborate solutions. The patients showed increased duration of long-gaze periods toward both parts of the screen. This suggests that the patients had difficulty in encoding the essential features of the stimulus array. This finding is compatible with slowing of working memory consolidation. |
J. M. Hagen; Josef N. Geest; R. S. Giessen; Gerardina C. Lagers-van Haselen; H. J. F. M. M. Eussen; J. J. P. Gille; L. C. P. Govaerts; C. H. Wouters; I. F. M. Coo; C. C. Hoogenraad; Sebastiaan K. E. Koekkoek; Maarten A. Frens; N. Camp; A. Linden; M. C. E. Jansweijer; S. S. Thorgeirsson; Chris I. De Zeeuw Contribution of CYLN2 and GTF2IRD1 to neurological and cognitive symptoms in Williams Syndrome Journal Article In: Neurobiology of Disease, vol. 26, no. 1, pp. 112–124, 2007. @article{Hagen2007, Williams Syndrome (WS, [MIM 194050]) is a disorder caused by a hemizygous deletion of 25-30 genes on chromosome 7q11.23. Several of these genes including those encoding cytoplasmic linker protein-115 (CYLN2) and general transcription factors (GTF2I and GTF2IRD1) are expressed in the brain and may contribute to the distinct neurological and cognitive deficits in WS patients. Recent studies of patients with partial deletions indicate that hemizygosity of GTF2I probably contributes to mental retardation in WS. Here we investigate whether CYLN2 and GTF2IRD1 contribute to the motoric and cognitive deficits in WS. Behavioral assessment of a new patient in which STX1A and LIMK1, but not CYLN2 and GTF2IRD1, are deleted showed that his cognitive and motor coordination functions were significantly better than in typical WS patients. Comparative analyses of gene specific CYLN2 and GTF2IRD1 knockout mice showed that a reduced size of the corpus callosum as well as deficits in motor coordination and hippocampal memory formation may be attributed to a deletion of CYLN2, while increased ventricle volume can be attributed to both CYLN2 and GTF2IRD1. We conclude that the motor and cognitive deficits in Williams Syndrome are caused by a variety of genes and that heterozygous deletion of CYLN2 is one of the major causes responsible for such dysfunctions. |
Z. I. Wang; Louis F. Dell'Osso In: Vision Research, vol. 47, no. 11, pp. 1550–1560, 2007. @article{Wang2007, The objective of this study was to investigate the dynamic properties of infantile nystagmus syndrome (INS) that affect visual function; i.e., which factors influence latency of the initial reflexive saccade (Ls) and latency to target acquisition (Lt). We used our behavioral ocular motor system (OMS) model to simulate saccadic responses (in the presence of INS) to target jumps at different times within a single INS cycle and at random times during multiple cycles. We then studied the responses of 4 INS subjects with different waveforms to test the model's predictions. Infrared reflection was used for 1 INS subject, high-speed digital video for 3. We recorded and analyzed human responses to large and small target-step stimuli. We evaluated the following factors: stimulus time within the cycle (Tc), normalized Tc (Tc%), initial orbital position (Po), saccade amplitude, initial retinal error (ei), and final retinal error (ef). The ocular motor simulations were performed in MATLAB Simulink environment and the analysis was performed in MATLAB environment using OMLAB software. Both the OMS model and OMtools software are available from http://http:www.omlab.org. Our data analysis showed that for each subject, Ls was a fixed value that is typically higher than the normal saccadic latency. Although saccadic latency appears somewhat lengthened in INS, the amount is insufficient to cause the "slow-to-see" impression. For Lt, Tc% was the most influential factor for each waveform type. The main refixation strategies employed by INS subjects made use of slow and fast phases and catch-up saccades, or combinations of them. These strategies helped the subjects to foveate effectively after target movement, sometimes at the cost of increased target acquisition time. Foveating or braking saccades intrinsic to the nystagmus waveforms seemed to disrupt the OMS' ability to accurately calculate reflexive saccades' amplitude and refoveate. Our OMS model simulations demonstrated this emergent behavior and predicted the lengthy target acquisition times found in the patient data. |
Zhong I. Wang; Louis F. Dell'Osso; Robert L. Tomsak; Jonathan B. Jacobs In: Journal of AAPOS, vol. 11, no. 2, pp. 135–141, 2007. @article{Wang2007a, Purpose: To investigate the effects of combined tenotomy and recession procedures on both acquired downbeat nystagmus and horizontal infantile nystagmus. Methods: Patient 1 had downbeat nystagmus with a chin-down (upgaze) position, oscillopsia, strabismus, and diplopia. Asymmetric superior rectus recessions and inferior rectus tenotomies reduced right hypertropia and rotated both eyes downward. Patient 2 had horizontal infantile nystagmus, a 20° left-eye exotropia, and alternating (abducting-eye) fixation. Lateral rectus recessions and medial rectus tenotomies were performed. Horizontal and vertical eye movements were recorded pre- and postsurgically using high-speed digital video. The eXpanded Nystagmus Acuity Function (NAFX) and nystagmus amplitudes and frequencies were measured. Results: Patient 1: The NAFX peak moved from 10° up to primary position where NAFX values improved 17% and visual acuity increased 25%. Vertical NAFX increased across the -10° to +5° vertical range. Primary-position right hypertropia decreased ∼50%; foveation time per cycle increased 102%; vertical amplitude, oscillopsia, and diplopia were reduced, and frequency was unchanged. Patient 2: Two lateral, narrow high-NAFX regions (due to alternating fixation) became one broad region with a 43% increase in primary position (acuity increased ∼92.3%). Diplopia amplitude decreased; convergence and gaze holding were improved. Primary-position right exotropia was reduced; foveation time per cycle increased 257%; horizontal-component amplitude decreased 45.7%, and frequency remained unchanged. Conclusions: Combining tenotomy with nystagmus or strabismus recession procedures increased NAFX and visual acuities and reduced diplopia and oscillopsia in downbeat nystagmus and infantile nystagmus. |
Philip J. Benson; Ute Leonards; Robert M. Lothian; David M. St. Clair; Marco C. G. Merlo Visual scan paths in first-episode schizophrenia and cannabis-induced psychosis Journal Article In: Journal of Psychiatry and Neuroscience, vol. 32, no. 4, pp. 267–274, 2007. @article{Benson2007, OBJECTIVE: Patterns of successive saccades and fixations (scan paths) that are made while viewing images are often spatially restricted in schizophrenia, but the relation with cannabis-induced psychosis has not been examined. We used higher-order statistical methods to examine spatiotemporal characteristics of scan paths to determine whether viewing behaviour was distinguishable on a continuum. METHODS: Patients with early acute first-episode paranoid schizophrenia (SCH; n = 11), cannabis-induced psychosis (CIP; n = 6) and unaffected control subjects (n = 22) undertook a task requiring free viewing of facial, fractal and landscape images for 5 seconds while their eye movements were recorded. Frequencies and distributions of saccades and fixations were calculated in relation to image regions examined during each trial. RESULTS: Findings were independent of image category, indicating generalized scanning deficits. Compared with control subjects, patients with SCH and CIP made fewer saccades and fewer fixations of longer duration. In turn, the spatial distribution of fixations in CIP patients was more clustered than in SCH and control subjects. The diversity of features fixated in subjects with CIP was also lower than in SCH patients and control subjects. CONCLUSION: A continuous approach to characterizing scan path changes in different phenotypes suggests that CIP shares some of the abnormalities of SCH but can be distinguished with measures that are sensitive to cognitive strategies active or inhibited during visual exploration. |
Rebecca J. McLean; Frank A. Proudlock; Shery Thomas; Christopher Degg; Irene Gottlob Congenital nystagmus: Randomized, controlled, double-masked trial of memantine/gabapentin Journal Article In: Annals of Neurology, vol. 61, no. 2, pp. 130–138, 2007. @article{McLean2007, OBJECTIVE: Nystagmus consists of involuntary to and fro movements of the eyes. Although studies have shown that memantine and gabapentin can reduce acquired nystagmus, no drug treatment has been systematically investigated in congenital nystagmus. METHODS: We performed a randomized, double-masked, placebo-controlled study investigating the effects of memantine and gabapentin on congenital nystagmus over a period of 56 days. The primary outcome measure was logarithmic minimum angle of resolution (logMAR) visual acuity; the secondary outcome measures were nystagmus intensity and foveation, subjective questionnaires about visual function (VF-14) and social function. Analyses were by intention to treat. RESULTS: Forty-eight patients were included in the study. One patient in the placebo group dropped out. Patients were randomized into either a memantine group (n=16), gabapentin group (n=16), or placebo group (n=15). Mean visual acuity improvements showed a significant effect between treatment groups (F=6.2; p=0.004, analysis of variance) with improvement in both memantine and gabapentin groups. Participants with afferent visual defects showed poorer improvements in visual acuity to medication than those with apparently normal visual systems. However, eye movement recordings showed that both nystagmus forms improved in nystagmus intensity (F=7.7; p=0.001) and foveation (F=8.7; p=0.0007). Participants subjectively reported an improvement in vision after memantine and gabapentin treatment more often than in the placebo group (p=0.03). However, there were no significant differences between the treatment groups with visual function (VF-14) or social function questionnaires because all groups reported improvements. INTERPRETATION: Our findings show that pharmacological agents such as memantine and gabapentin can improve visual acuity, reduce nystagmus intensity, and improve foveation in congenital nystagmus. |
Tobias Pflugshaupt; Urs P. Mosimann; Wolfgang J. Schmitt; Roman Wartburg; Pascal Wurtz; Mathias Lüthi; Thomas Nyffeler; Christian W. Hess; René M. Müri To look or not to look at threat? Scanpath differences within a group of spider phobics Journal Article In: Journal of Anxiety Disorders, vol. 21, no. 3, pp. 353–366, 2007. @article{Pflugshaupt2007, Predicting the behavior of phobic patients in a confrontational situation is challenging. While avoidance as a major clinical component of phobias suggests that patients orient away from threat, findings based on cognitive paradigms indicate an attentional bias towards threat. Here we present eye movement data from 21 spider phobics and 21 control subjects, based on 3 basic oculomotor tasks and a visual exploration task that included close-up views of spiders. Relative to the control group, patients showed accelerated reflexive saccades in one of the basic oculomotor tasks, while the fear-relevant exploration task evoked a general slowing in their scanning behavior and pronounced oculomotor avoidance. However, this avoidance strongly varied within the patient group and was not associated with the scores from spider avoidance-sensitive questionnaire scales. We suggest that variation of oculomotor avoidance between phobics reflects different strategies of how they cope with threat in confrontational situations. |
Tobias Pflugshaupt; Thomas Nyffeler; Roman Wartburg; Pascal Wurtz; Mathias Lüthi; Daniela Hubl; Klemens Gutbrod; Freimut D. Juengling; Christian W. Hess; René M. Müri When left becomes right and vice versa: Mirrored vision after cerebral hypoxia Journal Article In: Neuropsychologia, vol. 45, no. 9, pp. 2078–2091, 2007. @article{Pflugshaupt2007a, The combination of acquired mirror writing and reading is an extremely rare neurological disorder. It is encountered when brain damaged patients prefer horizontally mirrored over normal script in writing and reading. Previous theories have related this pathology to a disinhibition of mirrored engrams in the non-dominant hemisphere, possibly accompanied by a reversal of the preferred scanning direction. Here, we report the experimental investigation of PR, a patient who developed pronounced mirror writing and reading following septic shock that caused hypoxic brain damage. A series of five oculomotor experiments revealed that the patient's preferred scanning direction was indeed reversed. However, PR showed striking scanpath abnormalities and mirror reversals that cannot be explained by previous theories. Considered together with mirror phenomena she displayed in neuropsychological tasks and everyday activities, our findings suggest a horizontal reversal of visual information on a perceptual level. In addition, a systematic manipulation of visual variables within two further experiments had dramatic effects on her mirror phenomena. When confronted with moving, flickering or briefly presented stimuli, PR showed hardly any left-right reversals. Not only do these findings underline the perceptual nature of her disorder, but also allow interpretation of the pathology in terms of a dissociation between visual subsystems. We speculate that early visual cortices are crucially involved in this dissociation. More generally, her mirrored vision may represent an extreme clinical manifestation of the relative instability of the horizontal axis in spatial vision. |
Paul Sauleau; Pierre Pollak; Paul Krack; Denis Pélisson; Alain Vighetto; Alim Louis Benabid; Caroline Tilikete Contraversive eye deviation during stimulation of the subthalamic region Journal Article In: Movement Disorders, vol. 22, no. 12, pp. 1810–1813, 2007. @article{Sauleau2007, Contraversive eye deviation (CED) is most often observed intraoperatively during subthalamic nucleus implantation for Parkinson's disease and considered to result from wrong electrode positioning. We report on a woman, bilaterally implanted in the subthalamic nucleus for severe Parkinson's disease disclosing long-lasting CED only when the stimulators were activated separately. Clinical examination and eye movements recording in this patient showed that CED occurred when stimulation was applied at the site and at similar intensity used for the best antiparkinsonian effect. These results suggest that the subthalamic area may be involved in orienting movements, either through the subthalamic nucleus itself or the fibers from the Frontal Eye Fields. Interestingly, this report shows that CED may be corrected by bilateral stimulation and that CED may not necessarily implicate electrode repositioning. |
Daniel Smilek; Kelly A. Malcolmson; Jonathan S. A. Carriere; Meghan Eller; Donna Kwan; Michael G. Reynolds When "3" is a jerk and "E" is a king: Personifying inanimate objects in synesthesia Journal Article In: Journal of Cognitive Neuroscience, vol. 19, no. 6, pp. 981–992, 2007. @article{Smilek2007, We report a case study of an individual (TE) for whom inanimate objects, such as letters, numbers, simple shapes, and even furniture, are experienced as having rich and detailed personalities. TE reports that her object-personality pairings are stable over time, occur independent of her intentions, and have been there for as long as she can remember. In these respects, her experiences are indicative of synesthesia. Here we show that TE's object-personality pairings are very consistent across test-retest, even for novel objects. A qualitative analysis of TE's personality descriptions revealed that her personifications are extremely detailed and multi-dimensional, and that her personifications of familiar and novel objects differ in specific ways. We also found that TE's eye movements can be biased by the emotional associations she has with letters and numbers. These findings demonstrate that synesthesia can involve complex semantic personifications, which can influence visual attention. Finally, we propose a neural model of normal personification and the unusual personifications that accompany object-personality synesthesia. |
Michael L. Spezio; Ralph Adolphs; Robert S. Hurley; Joseph Piven Analysis of face gaze in autism using "Bubbles" Journal Article In: Neuropsychologia, vol. 45, no. 1, pp. 144–151, 2007. @article{Spezio2007a, One of the components of abnormal social functioning in autism is an impaired ability to direct eye gaze onto other people's faces in social situations. Here, we investigated the relationship between gaze onto the eye and mouth regions of faces, and the visual information that was present within those regions. We used the "Bubbles" method to vary the facial information available on any given trial by revealing only small parts of the face, and measured the eye movements made as participants viewed these stimuli. Compared to ten IQ- and age-matched healthy controls, eight participants with autism showed less fixation specificity to the eyes and mouth, a greater tendency to saccade away from the eyes when information was present in those regions, and abnormal directionality of saccades. The findings provide novel detail to the abnormal way in which people with autism look at faces, an impairment that likely influences all subsequent face processing. |
Michael L. Spezio; Ralph Adolphs; Robert S. Hurley; Joseph Piven Abnormal use of facial information in high-functioning autism Journal Article In: Journal of Autism and Developmental Disorders, vol. 37, no. 5, pp. 929–939, 2007. @article{Spezio2007, Altered visual exploration of faces likely contributes to social cognition deficits seen in autism. To investigate the relationship between face gaze and social cognition in autism, we measured both face gaze and how facial regions were actually used during emotion judgments from faces. Compared to IQ-matched healthy controls, nine high-functioning adults with autism failed to make use of information from the eye region of faces, instead relying primarily on information from the mouth. Face gaze accounted for the increased reliance on the mouth, and partially accounted for the deficit in using information from the eyes. These findings provide a novel quantitative assessment of how people with autism utilize information in faces when making social judgments. |
Bert Steenbergen; Julius Verrel; Andrew M. Gordon Motor planning in congenital hemiplegia Journal Article In: Disability and Rehabilitation, vol. 29, no. 1, pp. 13–23, 2007. @article{Steenbergen2007, PURPOSE: Cerebral Palsy (CP) is a broad definition of a neurological condition in which disorders in movement execution and postural control limit the performance of activities of daily living. In this paper, we first review studies on motor planning in hemiplegic CP. Second, preliminary data of a recent study on eye-hand coordination in participants with hemiplegic CP are presented. Here, the potential role of vision for online and prospective control of action was examined. METHOD: Review and presentation of preliminary data of an eye- and hand movement registration experiment in hemiplegic CP. RESULTS: Deficits in motor planning in hemiplegic CP contribute to limitations of activities of daily living. In the second part, exemplary plots of eye-hand coordination are presented for the affected and unaffected hand in one participant with hemiplegic CP, and for the preferred hand in controls, both as an illustration of the research methodology and to give an impression of the observed gaze patterns. CONCLUSION: Research on CP should not solely focus on low-level aspects of action execution, but also take into account the more high-level aspects of motor control, such as planning. Possible deviations therein may be sought in altered gaze patterns as illustrated in the paper. |
Rebecca L. Johnson; Keith Rayner Top-down and bottom-up effects in pure alexia: Evidence from eye movements Journal Article In: Neuropsychologia, vol. 45, no. 10, pp. 2246–2257, 2007. @article{Johnson2007, The eye movements of a patient with pure alexia, GJ, were recorded as he read sentences in order to explore the roles of top-down and bottom-up information during letter-by-letter reading. Specifically, the effects of word frequency and word predictability were examined. Additional analyses examined the interaction of these effects with the lower level influences of word length and letter confusability. The results indicate that GJ is sensitive to all four of these variables in sentence reading. These findings support an interactive account of reading where letter-by-letter readers use both bottom-up and top-down information to decode words. Due to the disrupted bottom-up processes caused by damage to the Visual Word Form Area or the input connections to it, pure alexic patients rely more heavily on intact top-down information in reading. |
Anouk Lamontagne; Caroline Paquette; Joyce Fung Stroke affects the coordination of gaze and posture during preplanned turns while walking Journal Article In: Neurorehabilitation and Neural Repair, vol. 21, no. 1, pp. 62–67, 2007. @article{Lamontagne2007, BACKGROUND: In healthy subjects, the act of walking and turning is accomplished by a sequential horizontal reorientation of gaze, head, and body toward the direction of the turn. Subjects with stroke, however, have difficulty altering their walking direction and present with loss of balance when performing a head turn or whole body rotation. OBJECTIVE: To study, in a pilot case study, the spatial and temporal coordination of gaze and posture during preplanned turns executed while walking in severely disabled and mildly disabled subjects with stroke as compared to a healthy control walking at slow speed. METHODS: Horizontal plane orientations of gaze, head, thorax, pelvis, and feet as well as the body's center of mass (CoM) trajectory were analyzed as subjects were walking straight or executing a 90-deg turn. RESULTS: Subjects with stroke revealed altered orientation and sequencing of gaze body segments. These alterations were more pronounced in the most severely disabled subject with stroke, especially when turning to the nonparetic side as compared to the paretic side. CONCLUSIONS: These findings suggest an altered coordination of gaze and posture during steering of locomotion in subjects with stroke. This altered coordination is likely due to a complex interaction of motor, sensory, and biomechanical factors that may explain the poor balance and poor control of heading direction during walking and turning in stroke. |
Mark F. Lenzenweger; Geoff McLachlan; Donald B. Rubin Resolving the latent structure of schizophrenia endophenotypes using expectation-maximization-based finite mixture modeling Journal Article In: Journal of Abnormal Psychology, vol. 116, no. 1, pp. 16–29, 2007. @article{Lenzenweger2007, Prior research has focused on the latent structure of endophenotypic markers of schizophrenia liability, or schizotypy. The work supports the existence of 2 relatively distinct latent classes and derives largely from the taxometric analysis of psychometric values. The present study used finite mixture modeling as a technique for discerning latent structure and the laboratory-measured endophenotypes of sustained attention deficits and eye-tracking dysfunction as endophenotype indexes. In a large adult community sample (N=311), finite mixture analysis of the sustained attention index d' and 2 eye-tracking indexes (gain and catch-up saccade rate) revealed evidence for 2 latent components. A putative schizotypy class accounted for 27% of the sample. A supplementary maximum covariance taxometric analysis yielded highly consistent results. Subjects in the schizotypy component displayed higher rates of schizotypal personality features and an increased rate of treated schizophrenia in their 1st-degree biological relatives compared with subjects in the other component. Implications of these results are examined in light of major theories of schizophrenia liability, and methodological advantages of finite mixture modeling for psychopathology research, with particular emphasis on genomic issues, are discussed. |
Chloé Prado; Matthieu Dubois; Sylviane Valdois The eye movements of dyslexic children during reading and visual search: Impact of the visual attention span Journal Article In: Vision Research, vol. 47, no. 19, pp. 2521–2530, 2007. @article{Prado2007, The eye movements of 14 French dyslexic children having a VA span reduction and 14 normal readers were compared in two tasks of visual search and text reading. The dyslexic participants made a higher number of rightward fixations in reading only. They simultaneously processed the same low number of letters in both tasks whereas normal readers processed far more letters in reading. Importantly, the children's VA span abilities related to the number of letters simultaneously processed in reading. The atypical eye movements of some dyslexic readers in reading thus appear to reflect difficulties to increase their VA span according to the task request. |
Annie Roy-Charland; Jean Saint-Aubin; Mary Ann Evans Eye movements in shared book reading with children from kindergarten to Grade 4 Journal Article In: Reading and Writing, vol. 20, no. 9, pp. 909–931, 2007. @article{RoyCharland2007, Previous studies have revealed that preschool-age children who are not yet readers pay little attention to written text in a shared book reading situation (see Evans & Saint-Aubin, 2005). The current study was aimed at investigating the constancy of these results across reading development, by monitoring eye movements in shared book reading, for children from kindergarten to Grade 4. Children were read books of three difficulty levels. The results revealed a higher proportion of time, a higher proportion of landing positions, and a higher proportion of reading-like saccades on the text as grade level increased and as reading skills improved. More precisely, there was a link between the difficulty of the material and attention to text. Children spent more time on a text that was within their reading abilities than when the book difficulty exceeded their reading skills. |
Jennifer D. Ryan; Grace Leung; Nicholas B. Turk-Browne; Lynn Hasher Assessment of age-related changes in inhibition and binding using eye movement monitoring Journal Article In: Psychology and Aging, vol. 22, no. 2, pp. 239–250, 2007. @article{Ryan2007, Age-related memory deficits may result from attending to too much information (inhibition deficit) and/or storing too little information (binding deficit). The present study evaluated the inhibition and binding accounts by exploiting a situation in which deficits of inhibition should benefit relational memory binding. Older adults directed more viewing toward abrupt onsets in scenes compared with younger adults under instructions to ignore any such onsets, providing evidence for age-related inhibitory deficits, which were ameliorated with additional practice. Subsequently, objects that served as abrupt onsets underwent changes in their spatial relations. Despite successful inhibition of the onsets, eye movements of younger adults were attracted to manipulated objects. In contrast, the eye movements of older adults, who directed more viewing to the late onsets compared with younger adults, were not attracted toward manipulated regions. Similar differences between younger and older adults in viewing of manipulated regions were observed under free viewing conditions. These findings provide evidence for concurrent inhibition and binding deficits in older adults and demonstrate that age-related declines in inhibitory processing do not lead to enhanced relational memory for extraneous information. |
Susan Sullivan; Ted Ruffman; Samuel B. Hutton Age differences in emotion recognition skills and the visual scanning of emotion faces Journal Article In: Journals of Gerontology - Series B Psychological Sciences and Social Sciences, vol. 62, no. 1, pp. 53–60, 2007. @article{Sullivan2007, Research suggests that a person's emotion recognition declines with advancing years. We examined whether or not this age-related decline was attributable to a tendency to overlook emotion information in the eyes. In Experiment 1, younger adults were significantly better than older adults at inferring emotions from full faces and eyes, though not from mouths. Using an eye tracker in Experiment 2, we found young adults, in comparison with older adults, to have superior emotion recognition performance and to look proportionately more to eyes than mouths. However, although better emotion recognition performance was significantly correlated with more eye looking in younger adults, the same was not true in older adults. We discuss these results in terms of brain changes with age. |
Corinne Tremblay; François Champoux; Patrice Voss; Benoit A. Bacon; Franco Lepore; Hugo Théoret Speech and non-speech audio-visual illusions: A developmental study Journal Article In: PLoS ONE, vol. 2, no. 8, pp. e742, 2007. @article{Tremblay2007, It is well known that simultaneous presentation of incongruent audio and visual stimuli can lead to illusory percepts. Recent data suggest that distinct processes underlie non-specific intersensory speech as opposed to non-speech perception. However, the development of both speech and non-speech intersensory perception across childhood and adolescence remains poorly defined. Thirty-eight observers aged 5 to 19 were tested on the McGurk effect (an audio-visual illusion involving speech), the Illusory Flash effect and the Fusion effect (two audio-visual illusions not involving speech) to investigate the development of audio-visual interactions and contrast speech vs. non-speech developmental patterns. Whereas the strength of audio-visual speech illusions varied as a direct function of maturational level, performance on non-speech illusory tasks appeared to be homogeneous across all ages. These data support the existence of independent maturational processes underlying speech and non-speech audio-visual illusory effects. |
Géry D'Ydewalle; Wim De Bruycker Eye movements of children and adults while reading television subtitles Journal Article In: European Psychologist, vol. 12, no. 3, pp. 196–205, 2007. @article{DYdewalle2007, Eye movements of children (Grade 5–6) and adults were monitored while they were watching a foreign language movie with either standard (foreign language soundtrack and native language subtitling) or reversed (foreign language subtitles and native language soundtrack) subtitling. With standard subtitling, reading behavior in the subtitle was observed, but there was a difference between one- and two-line subtitles. As two lines of text contain verbal information that cannot easily be inferred from the pictures on the screen, more regular reading occurred; a single text line is often redundant to the information in the picture, and accordingly less reading of one-line text was apparent. Reversed subtitling showed even more irregular reading patterns (e.g., more subtitles skipped, fewer fixations, longer latencies). No substantial age differences emerged, except that children took longer to shift attention to the subtitle at its onset, and showed longer fixations and shorter saccades in the text. On the whole, the results demonstrated the flexibility of the attentional system and its tuning to the several information sources available (image, soundtrack, and subtitles). |
Alison Firestone; Nicholas B. Turk-Browne; Jennifer D. Ryan Age-related deficits in face recognition are related to underlying changes in scanning behavior Journal Article In: Aging, Neuropsychology, and Cognition, vol. 14, no. 6, pp. 594–607, 2007. @article{Firestone2007, Previous studies demonstrating age-related impairments in recognition memory for faces are suggestive of underlying differences in face processing. To study these differ-ences, we monitored eye movements while younger and older adults viewed younger and older faces. Compared to the younger group, older adults showed increased sampling of facial features, and more transitions. However, their scanning behavior was most similar to the younger group when looking at older faces. Moreover, while older adults exhibited worse recognition memory than younger adults overall, their memory was more accurate for older faces. These findings suggest that age-related differences in recognition memory for faces may be related to changes in scanning behavior, and that older adults may use social group status as a compensatory processing strategy. |
Stefan Van der Stigchel; N. N. J. Rommelse; J. -B. Deijen; C. J. A. Geldof; J. Witlox; Jaap Oosterlaan; J. A. Sergeant; Jan Theeuwes Oculomotor capture in ADHD Journal Article In: Cognitive Neuropsychology, vol. 24, no. 5, pp. 535–549, 2007. @article{VanderStigchel2007c, It is generally thought that deficits in response inhibition form an important area of dysfunction in patients with attention-deficit/hyperactivity disorder (ADHD). However, recent research using visual search paradigms seems to suggest that these inhibitory deficits do not extend towards inhibiting irrelevant distractors. Using an oculomotor capture task, the present study investigated whether boys with ADHD and their nonaffected brothers are impaired in suppressing reflexive eye movements to a task-irrelevant onset distractor. Results showed that boys with ADHD had slower responses than controls, but were as accurate in their eye movements as controls. Nonaffected brothers showed similar problems in the speed of responding as their affected brothers, which might suggest that this deficit relates to a familial risk for developing the disorder. Importantly, all three groups were equally captured by the distractor, which shows that boys with ADHD and their brothers are not more distracted by the distractor than are controls. Saccade latency and the proportion of intrusive saccades were related to continuous dimensions of ADHD symptoms, which suggests that these deficits are not simply present or absent, but rather indicate that the severity of these deficits relate to the severity of ADHD. The finding that boys with ADHD (and their nonaffected brothers) did not have problems inhibiting irrelevant distractors contradicts a general response inhibition deficiency in ADHD, which may be explained by the relatively independency of working memory in this type of response inhibition. |
Ensar Becic; Arthur F. Kramer; Walter R. Boot Age-related differences in the use of background layout in visual search Journal Article In: Aging, Neuropsychology, and Cognition, vol. 14, no. 2, pp. 109–125, 2007. @article{Becic2007, The effect of background layout on visual search performance, and more specifically on the tendency to refixate previously inspected locations and objects, was investigated. Older and younger adults performed a search task in which a background layout or landmark was present or absent in a gaze contingent visual search paradigm. Regardless of age, participants demonstrated fewer refixations when landmarks were present, with older adults showing a larger landmark advantage. This visual search advantage did not come at the cost of saccadic latency. Furthermore, the visual search performance advantage obtained in the presence of a background layout or landmark was observed both for individuals with small and large memory spans. |
Eva Belke; Antje S. Meyer Single and multiple object naming in healthy ageing Journal Article In: Language and Cognitive Processes, vol. 22, no. 8, pp. 1178–1211, 2007. @article{Belke2007, We compared the performance of young (college-aged) and older (50'years) speakers in a single object and a multiple object naming task and assessed their susceptibility to semantic and phonological context effects when producing words amidst semantically or phonologically similar or dissimilar words. In single object naming, there were no performance differences between the age groups. In multiple object naming, we observed significant age-related slowing, expressed in longer gazes to the objects and slower speech. In addition, the direction of the phonological context effects differed for the two groups. The results of a supplementary experiment showed that young speakers, when adopting a slow speech rate, coordinated their eye movements and speech differently from the older speakers. Our results imply that age-related slowing in connected speech is not a direct consequence of a slowing of lexical retrieval processes. Instead, older speakers might allocate more processing capacity to speech monitoring processes, which would slow down their concurrent speech planning processes. |
Lisa R. Betts; Allison B. Sekuler; Patrick J. Bennett The effects of aging on orientation discrimination Journal Article In: Vision Research, vol. 47, no. 13, pp. 1769–1780, 2007. @article{Betts2007, The current experiments measured orientation discrimination thresholds in younger (mean age ≈ 23 years) and older (mean age ≈ 66 years) subjects. In Experiment 1, the contrast needed to discriminate Gabor patterns (0.75, 1.5, and 3 c/deg) that differed in orientation by 12 deg was measured for different levels of external noise. At all three spatial frequencies, discrimination thresholds were significantly higher in older than younger subjects when external noise was low, but not when external noise was high. In Experiment 2, discrimination thresholds were measured as a function of stimulus contrast by varying orientation while contrast was fixed. The resulting threshold-vs-contrast curves had very similar shapes in the two age groups, although the curve obtained from older subjects was shifted to slightly higher contrasts. At contrasts greater than 0.05, thresholds in both older and younger subjects were approximately constant at 0.5 deg. The results from Experiments 1 and 2 suggest that age differences in orientation discrimination are due solely to differences in equivalent input noise. Using the same methods as Experiment 1, Experiment 3 measured thresholds in 6 younger observers as a function of external noise and retinal illuminance. Although reducing retinal illumination increased equivalent input noise, the effect was much smaller than the age difference found in Experiment 1. Therefore, it is unlikely that differences in orientation discrimination were due solely to differences in retinal illumination. Our findings are consistent with recent physiological experiments that have found elevated spontaneous activity and reduced orientation tuning on visual cortical neurons in senescent cats (Hua, T., Li, X., He, L., Zhou, Y., Wang, Y., Leventhal, A. G. (206). Functional degradation of visual cortical cells in old cats. |
2006 |
Meredyth Daneman; Brenda Hannon; Christine Burton Are There Age-Related Differences in Shallow Semantic Processing of Text? Evidence From Eye Movements Journal Article In: Discourse Processes, vol. 42, no. 2, pp. 177–203, 2006. @article{Daneman2006, After reading text such as Amanda was bouncing all over because she had taken too many tranquilizing sedatives in one day, young adult readers frequently fail to report that they noticed the anomalous noun phrase (NP). Although young readers of all skill levels are susceptible to this kind of shallow semantic processing, less-skilled readers are more susceptible and have particular difficulty detecting locally anomalous NPs such as tranquilizing stimulants. This article explores whether aging has a similar impact on a reader's propensity toward shallow semantic processing. Postreading responses showed that older readers frequently failed to report the anomalous NPs, but no more frequently than did younger readers. The eye-fixation behavior revealed that older readers actually detected the locally coherent anomalous NPs (e.g., tranquilizing sedatives) sooner than did younger readers, but had to allocate disproportionately more processing resources looking back to the locally incoherent anomalous NPs (tranquilizing stimulants) to achieve comparable levels of detection success as their younger counterparts. |
Inger Montfoort; Willem P. A. Kelders; Josef N. Geest; Inger B. Schipper; Louw Feenstra; Chris I. De Zeeuw; Maarten A. Frens Interaction between ocular stabilization reflexes in patients with whiplash injury Journal Article In: Investigative Ophthalmology & Visual Science, vol. 47, no. 7, pp. 2881–2884, 2006. @article{Montfoort2006, PURPOSE: In the past few decades, the automobile has become an increasingly more popular means of transport, which has led to an increasing number of rear-end collisions and consequently has resulted in more patients with whiplash-associated disorders (WADs). Recently, it was found that the gain of one of the ocular stabilization reflexes-the cervico-ocular reflex (COR)-is elevated in patients with whiplash injury. The COR responds to proprioceptive signals from the neck and acts in conjunction with the vestibulo-ocular reflex (VOR) and the optokinetic reflex (OKR) to preserve stable vision on the retina during head motion. Therefore, an investigation was conducted to determine whether the reported elevation of the COR in WADs is accompanied by changes in VOR or OKR. METHODS: Eye movements of 13 patients and 18 age-matched healthy controls were recorded with an infrared eye-tracking device. RESULTS: Analysis confirmed a significant increase in COR gain in whiplash patients. Meanwhile the VOR and OKR gains remained the same. No correlation was found between the gains of the reflexes in individual patients. This is in contrast to earlier observations in elderly subjects and subjects with labyrinthine defects, who showed increases in COR gain and decreases in VOR gain. CONCLUSIONS: Impaired neck motion, altered proprioception of the neck, or disorganization in the process of VOR plasticity could explain the lack of change in VOR gain. |
Dirk Neumann; Michael L. Spezio; Joseph Piven; Ralph Adolphs Looking you in the mouth: Abnormal gaze in autism resulting from impaired top-down modulation of visual attention Journal Article In: Social Cognitive and Affective Neuroscience, vol. 1, no. 3, pp. 194–202, 2006. @article{Neumann2006, People with autism are impaired in their social behavior, including their eye contact with others, but the processes that underlie this impairment remain elusive. We combined high-resolution eye tracking with computational modeling in a group of 10 high-functioning individuals with autism to address this issue. The group fixated the location of the mouth in facial expressions more than did matched controls, even when the mouth was not shown, even in faces that were inverted and most noticeably at latencies of 200-400 ms. Comparisons with a computational model of visual saliency argue that the abnormal bias for fixating the mouth in autism is not driven by an exaggerated sensitivity to the bottom-up saliency of the features, but rather by an abnormal top-down strategy for allocating visual attention. |
Helena Ojanpää; Risto Näsänen; Juha Päällysaho; Ritva Akila; Kiti Müller; Ari Kaukiainen; Markku Sainio Visual search and eye movements in patients with chronic solvent-induced toxic encephalopathy Journal Article In: Neurotoxicology, vol. 27, no. 6, pp. 1013–1023, 2006. @article{Ojanpaeae2006, Various aspects of visual perception have been found to be impaired in patients with occupational chronic solvent-induced toxic encephalopathy (CSE). The purpose of the study was to characterise the changes in eye movements and visual search performance in CSE patients. We measured eye movements of 13 CSE patients and 22 healthy controls during dynamic visual search task by using a fast video eye tracker. The task was to search for and identify a target letter among numerals presented in a rectangular stimulus matrix (3 × 3-10 × 10 items). Threshold search time, i.e. the duration of stimulus presentation required for identifying the target with a given probability was determined by using a psychophysical staircase method. The visual search times of the CSE patients were clearly longer, and they needed considerably more eye fixations than healthy controls to find the target. Thus, their reduced performance in this task was mainly related to the reduction in the number of items which could be processed during a single eye fixation (perceptual span). This reduction probably reflects a limited capacity of visual attention, since visual acuity, contrast sensitivity, and the oculomotor saccade velocity were found to be normal. The results suggest that motor slowness or low-level visual factors do not explain the poor performance of CSE patients in visual search tasks. The results are also discussed with respect to the effects of education, and compared to the performance in the widely used neuropsychological Trail Making Test, which uses similar stimuli and requires visual search. © 2006 Elsevier Inc. All rights reserved. |
Jay Pratt; Michael Dodd; Timothy N. Welsh Growing older does not always mean moving slower: Examining aging and the saccadic motor system Journal Article In: Journal of Motor Behavior, vol. 38, no. 5, pp. 373–382, 2006. @article{Pratt2006, Although humans typically move more slowly as they age, one exception may be the saccadic motor system. To fully determine whether the execution of saccades is affected by age, the authors examined detailed kinematics of vertical and horizontal saccades across a range of saccadic amplitudes (4 degrees, 8 degrees, and 12 degrees). Ten younger and 20 older adults participated in each experiment. Whereas in the 1st experiment, the authors assessed volitionally generated saccades, in the 2nd experiment, they evaluated reflexively generated saccades. The results of those experiments showed that the saccadic motor system is relatively impervious to the effects of aging; in fact, the differences between vertical and horizontal saccades were more evident than were differences between saccades produced by younger and older adults. The authors discuss possible reasons for that relative resistance to aging. |
Keith Rayner; Erik D. Reichle; Michael J. Stroud; Carrick C. Williams; Alexander Pollatsek The effect of word frequency, word predictability, and font difficulty on the eye movements of young and older readers Journal Article In: Psychology and Aging, vol. 21, no. 3, pp. 448–465, 2006. @article{Rayner2006b, Young adult and older readers' eye movements were recorded as they read sentences containing target words that varied in frequency or predictability. In addition, half of the sentences were printed in a font that was easy to read (Times New Roman) and the other half were printed in a font that was more difficult to read (Old English). Word frequency, word predictability, and font difficulty effects were apparent in the eye movement data of both groups of readers. In the fixation time data, the pattern of results was the same, but the older readers had larger frequency and predictability effects than the younger readers. The older readers skipped words more often than the younger readers (as indicated by their skipping rate on selected target words), but they made more regressions back to the target words and more regressions overall. The E-Z Reader model was used as a platform to evaluate the results, and simulations using the model suggest that lexical processing is slowed in older readers and that, possibly as a result of this, they adopt a more risky reading strategy. |
Jennifer D. Ryan; Jiye Shen; Eyal M. Reingold Modulation of distraction in ageing Journal Article In: British Journal of Psychology, vol. 97, no. 3, pp. 339–351, 2006. @article{Ryan2006, A cueing paradigm was employed to examine modulation of distraction due to a visual singleton. Subjects were required to make a saccade to a shape-singleton target. A predictive location cue indicated the hemifield where a target would appear. Older adults made more anticipatory saccades than younger adults, and were less accurate for making an eye movement in the vicinity of a target. However, younger and older adults likewise benefited from the cue; distraction was reduced when the distractor singleton appeared in an uncued hemisphere. The ability to compensate for problems with distraction in older and younger adults through use of the precue suggests that attention to a general region of space, rather than a specific location, may be enough to modulate distraction. |
Arthur F. Kramer; Walter R. Boot; Jason S. McCarley; Matthew S. Peterson; Angela M. Colcombe; Charles T. Scialfa Aging, memory and visual search Journal Article In: Acta Psychologica, vol. 122, no. 3, pp. 288–304, 2006. @article{Kramer2006, Potential age-related differences in the memory processes that underlie visual search are examined in the present study. Using a dynamic, gaze-contingent search paradigm developed to assess memory for previously examined distractors, older adults demonstrated no memory deficit. Surprisingly, older adults made fewer refixations compared to their younger counterparts, indicating better memory for previously inspected objects. This improved memory was not the result of a speed-accuracy trade-off or larger Inhibition-of-Return effects for older than for younger adults. Additional analyses suggested that older adults may derive their benefit from finer spatial encoding of search items. These findings suggest that some of the memory processes that support visual search are relatively age invariant. |
C. Hanisch; Ralph Radach; K. Holtkamp; B. Herpertz-Dahlmann; Kerstin Konrad Oculomotor inhibition in children with and without attention-deficit hyperactivity disorder (ADHD) Journal Article In: Journal of Neural Transmission, vol. 113, no. 5, pp. 671–684, 2006. @article{Hanisch2006, The aim of the present study was to distinguish between a general deficit in oculomotor control and a deficit restricted to inhibitory functions in children with attention deficit hyperactivity disorder (ADHD). In addition, we were interested in differentiating between a general inhibition deficit and deficient subfunctions of inhibition. We used a prosaccade task to measure general oculomotor abilities in 22 children with ADHD and in age- and gender-matched healthy controls. A fixation, an antisaccade and a countermanding saccade task were used to measure specific aspects of oculomotor inhibition. Two major results were obtained: First, our prosaccade task suggests similar saccadic response preparation and saccadic accuracy in the ADHD compared to the control children. Secondly, the fixation and the countermanding saccade task indicate deficits on measures of oculomotor inhibition in the ADHD group. While patients were specifically impaired in stopping an already initiated response or in suppressing exploratory saccades in a novel situation, inhibition of a prepotent response was not deficient. Our data thus indicate an underlying impairment in cognitive inhibition in ADHD that has been associated with prefrontal lobe functions. More specifically, as the anterior cingulate gyrus has been associated with the countermanding saccade task and group differences were most pronounced in this paradigm our data are in line with imaging data stressing the importance of this cortical structure in the pathophysiology of ADHD. |
Trevor J. Hine; Guy Wallis; Joanne M. Wood; Efty P. Stavrou Reflexive optokinetic nystagmus in younger and older observers under photopic and mesopic viewing conditions Journal Article In: Investigative Ophthalmology & Visual Science, vol. 47, no. 12, pp. 5288–5294, 2006. @article{Hine2006, PURPOSE: To investigate the effect of age on optokinetic nystagmus (OKN) in response to stimuli designed to preferentially stimulate the M-pathway. METHOD: OKN was recorded in 10 younger (32.3 +/- 5.98 years) and 10 older (65.6 +/- 6.53) subjects with normal vision. Vertical gratings of 0.43 or 1.08 cpd drifting at 5 degrees /s or 20 degrees /s and presented at either 8% or 80% contrast were displayed on a large screen as full-field stimulation, central stimulation within a central Gaussian-blurred window of 15 degrees diameter, or peripheral stimulation outside this window. All conditions apart from the high-contrast condition were presented in a random order at two light levels, mesopic (1.8 cdm(-2)) and photopic (71.5 cdm(-2)). RESULTS: Partial-field data indicated that central stimulation, mesopic light levels, and lower temporal frequency each significantly increased slow-phase velocity (SPV). Although there was no overall difference between groups for partial-field stimulation, full-field stimulation, or low-contrast stimulation, a change in illumination revealed a significant interaction with age: there was a larger decrease in SPV going from photopic to mesopic conditions for the older group than the younger group, especially for higher temporal frequency stimulation. CONCLUSIONS: OKN becomes reflexive in conditions conducive to M-pathway stimulation, and this rOKN response is significantly diminished in older healthy adults than in younger healthy adults, indicative of decreased M-pathway sensitivity. |
Florian Hutzler; Martin Kronbichler; Arthur M. Jacobs; Heinz Wimmer Perhaps correlational but not causal: No effect of dyslexic readers' magnocellular system on their eye movements during reading Journal Article In: Neuropsychologia, vol. 44, no. 4, pp. 637–648, 2006. @article{Hutzler2006, During reading, dyslexic readers exhibit more and longer fixations and a higher percentage of regressions than normal readers. It is still a matter of debate, whether these divergent eye movement patterns of dyslexic readers reflect an underlying problem in word processing or whether they are - as the proponents of the magnocellular deficit hypothesis claim - associated with deficient visual perception that is causal for dyslexia. To overcome problems in the empirical linkage of the magnocellular theory with reading, a string processing task is presented that poses similar demands on visual perception (in terms of letter identification) and oculomotor control as reading does. Two experiments revealed no differences in the eye movement patterns of dyslexic and control readers performing this task. Furthermore, no relationship between the functionality of the participants' magnocellular system assessed by the coherent motion task and string processing were found. The perceptual and oculomotor demands required during string processing were functionally equivalent to those during reading and the presented consonant strings had similar visual characteristics as reading material. Thus, a strong inference can be drawn: Dyslexic readers do not seem to have difficulties with the accurate perception of letters and the control of their eye movements during reading - their reading difficulties therefore cannot be explained in terms of oculomotor and visuo-perceptual problems. |
Stamatina A. Kabanarou; Michael D. Crossland; Caren Bellmann; Angela Rees; Louise E. Culham; Gary S. Rubin Gaze changes with binocular versus monocular viewing in age-related macular degeneration Journal Article In: Ophthalmology, vol. 113, no. 12, pp. 2251–2258, 2006. @article{Kabanarou2006, Purpose: To determine and explain gaze changes during binocular versus monocular viewing in patients with age-related macular degeneration (AMD). Design: Cross-sectional study. Participants: Twenty-nine patients with bilateral late-stage AMD. Methods: Distance acuity and fundus pathologic features were evaluated. Eye position was recorded while viewing a circular fixation target under monocular and binocular viewing conditions using an infrared eye tracker (SMI Gazetracker, SensoMotoric, Germany; Eyelink Software 2.04). Gaze changes were quantified by calculating the mean x-coordinate and y-coordinate eye position of the center of the bivariate contour ellipse area for a 30-second fixation task under both viewing conditions. Retinal loci used for monocular fixation for each eye were determined using the scanning laser ophthalmoscope (SLO; SLO 101, Rodenstock, Munich, Germany). Main Outcome Measure: Gaze position. Results: Nine patients showed no shift in gaze position from monocular to binocular viewing. Three patients demonstrated a shift in both eyes, and 17 patients demonstrated a shift in only 1 eye. The mean shift was 4.7±5° (standard deviation). The shift in gaze position in the worse eye was predictive of the distance between the 2 monocular preferred retinal loci (PRLs; better and worse eye; r2= 0.59; P<0.0001), whereas there was no association between the shift in gaze position in the better eye and distance (r2= 0.00; P = 0.91). Conclusions: Most AMD patients shift gaze position in 1 or both eyes when viewing binocularly compared with monocularly. These changes suggest that different retinal locations are used for fixation under the 2 viewing conditions. The SLO data showed that these patients are likely to demonstrate monocular PRLs that fall on noncorresponding areas. These results may have implications for the effective development of eccentric viewing and binocular behavior of AMD patients. |
Patricia E. G. Bestelmeyer; Benjamin W. Tatler; Louise H. Phillips; Gillian Fraser; Philip J. Benson; David St.Clair Global visual scanning abnormalities in schizophrenia and bipolar disorder Journal Article In: Schizophrenia Research, vol. 87, no. 1-3, pp. 212–222, 2006. @article{Bestelmeyer2006, Visual scanning of face images is widely reported to be abnormal in schizophrenia. This impaired processing has been proposed to be partly responsible for patients' disturbance in social interactions. The present study was designed to determine whether abnormal scanning is specific to images with social content or extends to other types of stimuli. Individuals with schizophrenia (n = 22), bipolar disorder (n = 19) and healthy controls (n = 37) were asked to view a series of 28 images with or without socially important content (i.e. faces, landscapes, fractals and noise patterns) while their eye movements were recorded video-oculographically. Temporal and spatial characteristics of scan paths were compared for each patient group and picture type. Independent of image content, patients with schizophrenia exhibited fewer fixations, longer fixation duration, longer saccade duration and peak velocity, and smaller saccade amplitude compared with healthy controls. Patients with schizophrenia and bipolar disorder did not differ significantly from one another on any of the temporal variables recorded. Fixation location distributions of participants with schizophrenia differed significantly from that of healthy controls on all picture types and from patients with bipolar disorder on all but face images. Abnormal scanning in schizophrenia and also bipolar disorder was independent of stimulus type and therefore reflects a global visual scanning impairment not specific to faces. Spatial scanning characteristics but not temporal ones may serve as biomarkers in the functional psychoses. |
Geoffrey Bird; Caroline Catmur; Giorgia Silani; Chris Frith; Uta Frith Attention does not modulate neural responses to social stimuli in autism spectrum disorders Journal Article In: NeuroImage, vol. 31, no. 4, pp. 1614–1624, 2006. @article{Bird2006, We investigated whether individuals with autism spectrum disorders (ASD) would show attentional modulation for social (face) and non-social (house) stimuli. Sixteen individuals with ASD and 16 matched control participants completed a task in which pairs of face and house stimuli were present on every trial, with one of the pairs randomly assigned to attended locations and the other to unattended locations. Both mass-univariate (SPM) and region of interest analyses suggested that responses to houses were modulated by attention in both groups, but that only the control participants demonstrated attentional modulation of face-selective regions. Thus, the participants with ASD demonstrated a lack of attentional modulation which was particularly evident for the social stimulus. Analyses of effective connectivity indicated that these results were due to a failure of attention to modulate connectivity between extrastriate areas and V1. We discuss how these results may suggest a mechanism to explain the reduced salience of social stimuli in ASD. |
Tanya Blekher; S. A. Johnson; James A. R. Marshall; K. White; S. Hui; Marjorie R. Weaver; J. Gray; Robert D. Yee; J. C. Stout; X. Berstian; Joanne Wojcieszek; Tatiana M. Foroud Saccades in presymptomatic and early stages of Huntington disease Journal Article In: Neurology, vol. 67, no. 2, pp. 394–399, 2006. @article{Blekher2006, OBJECTIVE:To evaluate quantitative measures of eye movements as possible biomarkers in prediagnostic and early stages of Huntington disease (HD). METHODS:The study sample (n = 215) included individuals both at risk and recently diagnosed with HD. All participants completed a uniform clinical evaluation which included administration of the Unified Huntington's Disease Rating Scale (UHDRS) by a movement disorder neurologist and molecular testing to determine HD gene status. A high resolution, video-based eye tracking system was employed to quantify measures of eye movement (error rates, latencies, SD of latencies, velocities, and accuracies) during a computerized battery of saccadic and steady fixation tasks. RESULTS:Prediagnostic HD gene carriers and individuals with early HD demonstrated three types of significant abnormalities while performing memory guided and anti-saccade tasks: increased error rate, increased saccade latency, and increased variability of saccade latency. The eye movement abnormalities increased with advancing motor signs of HD. CONCLUSIONS:Abnormalities in eye movement measures are a sensitive biomarker in the prediagnostic and early stages of Huntington disease (HD). These measures may be more sensitive to prediagnostic changes in HD than the currently employed neurologic motor assessment. |
Stephen H. Butler; Iain D. Gilchrist; Casimir J. H. Ludwig; Keith Muir; Monika Harvey Impairments of oculomotor control in a patient with a right temporo-parietal lesion Journal Article In: Cognitive Neuropsychology, vol. 23, no. 6, pp. 990–999, 2006. @article{Butler2006, Goal-driven control over saccade target selection requires the inhibition of task-irrelevant, stimulus-driven saccades. A widely held assumption is that frontal structures are of critical importance for this function. Here we report the oculomotor capture behaviour of a patient with a right temporo-parietal lesion, which challenges this view. T.H. was asked to search for a target among distractors and to signal its location with a saccade. A task-irrelevant, additional distractor appeared with or without abrupt onset, and it was either similar or dissimilar in its colour to the target. Compared to controls, T.H. showed an elevated level of capture overall. He also showed spatial extinction, which was partially overridden by an abrupt onset distractor. These results support the view that effective oculomotor control depends on an intact network of frontal and posterior brain regions. We argue that stimulus-driven and goal-driven signals are computed at different stages, but are ultimately combined in a common functional salience map. |
Thomas Habekost; Randi Starrfelt Alexia and quadrant-amblyopia: Reading disability after a minor visual field deficit Journal Article In: Neuropsychologia, vol. 44, no. 12, pp. 2465–2476, 2006. @article{Habekost2006, Reading difficulties caused by hemianopia are well described. We present a study of alexia in a patient (NT) with a milder visual field deficit. The patient had suffered a cerebral haemorrhage causing damage to the left occipital cortex and underlying white matter. NT's text reading was slow and prone to error, but recognition of single letters was preserved. Single word reading was accurate, but slower than normal. On perimetric testing NT initially showed an upper right quadrantanopia, but by attending covertly to this quadrant he could achieve luminance detection except in a small scotoma above the reading line. A whole report experiment showed that letter perception was severely compromised in the quadrant, consistent with cerebral amblyopia. On follow-up testing one and a half year post stroke, a clear spontaneous recovery had occurred, reflected in improved text reading with close to normal eye movements. Still, subtle reading difficulties and oculo-motor abnormalities remained. Overall, the study shows how amblyopia in one quadrant can lead to a characteristic form of alexia. |
Jonathan B. Jacobs; Louis F. Dell'Osso; Richard W. Hertle; Gregory M. Acland; Jean Bennett Eye movement recordings as an effectiveness indicator of gene therapy in RPE65-deficient canines: Implications for the ocular motor system Journal Article In: Investigative Ophthalmology & Visual Science, vol. 47, no. 7, pp. 2865–2875, 2006. @article{Jacobs2006, PURPOSE: To perform ocular motility recordings of infantile nystagmus (IN) in RPE65-deficient canines and determine whether they can be used as a motor indicator of restored retinal function to investigate the effects of gene therapy. METHODS: Treated and untreated canines were comfortably suspended in a custom-built sling and encouraged to fixate on distant targets at gaze angles varying between +/-15 degrees horizontally and +/-10 degrees vertically. Ocular motility recordings were made, using two distinct methods-infrared reflection and high-speed video. The resultant recordings from three untreated, four treated, and three pre- and post-treatment dogs were analyzed for using the eXpanded Nystagmus Acuity Function (NAFX), which yields an objective assessment of best potential visual acuity, based on the duration and repeatable accuracy of foveation and centralisation. RESULTS: During fixation, the untreated dogs exhibited large-amplitude, classic IN waveforms, including pendular and jerk in both the horizontal and vertical planes, which prevented them from keeping the targets within the area centralis (the region of highest receptor density, spanning +/-3 degrees horizontally by +/-1.5 degrees vertically, analogous to the fovea). Some untreated dogs also had small-amplitude (0.5-1 degrees), high-frequency (6-9 Hz) oscillations. Under the same conditions, successfully treated canines no longer exhibited clinically detectable IN. Their IN was converted to waveforms with very low amplitudes that yielded higher NAFX values and allowed target images to remain well within the area centralis. Of note, uniocular treatment appeared to damp the IN in both eyes. Behaviorally, the treated dogs were able to successfully navigate through obstacles more easily without inadvertent contact, a task beyond the untreated dogs' ability. CONCLUSIONS: Gene therapy that successfully restored retinal function also reduced the accompanying IN to such a great extent that it was not clinically detectable approximately 90% of the time in many of the dogs. IN improvement, as quantified by the NAFX, is an objective motor indicator of visual improvement due to gene therapy. |
Charlotte Golding; C. Danchaivijitr; Timothy L. Hodgson; Sarah J. Tabrizi; Christopher Kennard Identification of an oculomotor biomarker of preclinical Huntington disease Journal Article In: Neurology, vol. 67, no. 3, pp. 485–487, 2006. @article{Golding2006, The authors examined oculomotor function to identify a biomarker of disease progression in genetically confirmed preclinical and early clinical Huntington disease (HD). Initiation deficits of voluntary-guided, but not reflexive, saccades were characteristic of preclinical HD. Saccadic slowing and delayed reflexive saccades were demonstrated in clinical but not preclinical HD. Saccadic measures provide biomarkers of disease progression in both preclinical and early clinical stages of HD. |
Waheeda Rahman; Frank A. Proudlock; Irene Gottlob Oral gabapentin treatment for symptomatic Heimann-Bielschowsky Pphenomenon Journal Article In: American Journal of Ophthalmology, vol. 141, pp. 221–222, 2006. @article{Rahman2006, PURPOSE: To describe a patient with symptomatic Heimann-Bielschowsky phenomenon (HBP) treated suc- cessfully with oral gabapentin. DESIGN: Interventional case report. METHODS: A 57-year-old patient with retinitis pigmentosa had a 12-month history of vertical oscillopsia. The right visual acuity was 20/200 and the left visual acuity was 20/60 with glasses. He had a coarse, slow, pendular, vertical movement of the right eye consistent with Heimann- Bielschowsky phenomenon. His treatment commenced with oral gabapentin with gradual increase in dose to 2400 mg/d. Eye movement recordings were performed before and after treatment. RESULTS: He became considerably less symptomatic on gabapentin. The right visual acuity improved to 20/80 with glasses. Eye movement recordings confirmed mark- edly reduced vertical oscillations of the right eye. The patient continues on gabapentin with no side effects and sustained effect. CONCLUSIONS: The vertical nystagmoid movement in HBP can be considerably reduced and symptoms remarkably improved when treated with oral gabapentin. |
Nagini Sarvananthan; Frank A. Proudlock; I. Choudhuri; H. Dua; Irene Gottlob Pharmacologic treatment of congenital nystagmus Journal Article In: Archives of Ophthalmology, vol. 124, pp. 916–917, 2006. @article{Sarvananthan2006, Pharmacologic treatment has been used in acquired nystagmus with mixed success. Treatments have included baclofen, sodium valproate, gabapentin, and memantine. However, in congenital nystagmus, little is known about the effect of drugs. We describe a patient with congenital nystagmus and corneal dystrophy who improved dramati- cally with gabapentin treatment. |
Caroline Tilikete; Ansgar Koene; Norbert Nighoghossian; Alain Vighetto; Denis Pélisson Saccadic lateropulsion in Wallenberg syndrome: A window to access cerebellar control of saccades? Journal Article In: Experimental Brain Research, vol. 174, no. 3, pp. 555–565, 2006. @article{Tilikete2006, Saccadic lateropulsion is characterized by an undershoot of contralaterally directed saccades, an overshoot of ipsilaterally directed saccades and an ipsilateral deviation of vertical saccades. In Wallenberg syndrome, it is thought to result from altered signals in the olivo-cerebellar pathway to the oculomotor cerebellar network. In the current study we aimed to determine whether saccadic lateropulsion results from a cerebellar impairment of motor related signals or visuo-spatial related signals. We studied the trajectory, the accuracy, the direction and the amplitude of a variety of vertical and oblique saccades produced by five patients and nine control subjects. Some results are consistent with previous data suggesting altered motor related signals. Indeed, the horizontal error of contralesional saccades in patients increased with the desired horizontal saccade size. Furthermore, the initial directional error measured during the saccadic acceleration phase was smaller than the global directional error, suggesting that the eye trajectory curved progressively. However, some other results suggest that the processes that specify the horizontal spatial goal of the saccades might be impaired in the patients. Indeed, the horizontal error of ipsilesional saccades in patients did not change significantly with the desired horizontal saccade size. In addition, when comparing saccades with similar intended direction, it was found that the directional error was inversely related to the vertical saccade amplitude. Thus we conclude that the cerebellum might be involved both in controlling the motor execution of saccades and in determining the visuo-spatial information about their goal. |
Z. Wang; Louis F. Dell'Osso; Z. Zhang; R. John Leigh; Jonathan B. Jacobs Tenotomy does not affect saccadic velocities: Support for the "small-signal" gain hypothesis Journal Article In: Vision Research, vol. 46, no. 14, pp. 2259–2267, 2006. @article{Wang2006, We investigated the effects of four-muscle tenotomy on saccadic characteristics in infantile nystagmus syndrome (INS) and acquired pendular nystagmus (APN). Eye movements of 10 subjects with INS and one with APN were recorded using infrared reflection, magnetic search coil, or high-speed digital video. The expanded nystagmus acuity function (NAFX) quantified tenotomy-induced foveation changes in the INS. Saccadic characteristics and peak-to-peak nystagmus amplitudes were measured. Novel statistical tests were performed on the saccadic data. Six out of the 10 INS subjects showed no changes in saccadic duration, peak velocity, acceleration, or trajectory. In the other four, the differences were less than in peak-to-peak amplitudes (from 14.6% to 39.5%) and NAFX (from 22.2% to 162.4%). The APN subject also showed no changes despite a 50% decrease in peak-to-peak amplitude and a 34% increase in NAFX. The "small-signal" changes (peak-to-peak nystagmus amplitude and NAFX) were found to far exceed any "large-signal" changes (saccadic). Tenotomy successfully reduced INS and APN, enabling higher visual acuity without adversely affecting saccadic characteristics. These findings support the peripheral, small-signal gain reduction (via proprioceptive tension control) hypothesis. Current linear plant models, limited to normal steady-state muscle tension levels, cannot explain the effects of the tenotomy. |
Zhong Wang; Louis F. Dell'Osso; Jonathan B. Jacobs; Robert A. Burnstine; Robert L. Tomsak Effects of tenotomy on patients with infantile nystagmus syndrome: Foveation improvement over a broadened visual field Journal Article In: Journal of AAPOS, vol. 10, no. 6, pp. 552–560, 2006. @article{Wang2006a, Purpose: To investigate the effects of four-muscle tenotomy on visual function and gaze angle in patients with infantile nystagmus syndrome (INS). Methods: Eye movements of nine patients with infantile nystagmus were recorded using infrared reflection or high-speed digital video techniques. Experimental protocols were designed to record the patients' eye-movement waveforms, pre- and post-tenotomy, at different gaze angles. We used the eXpanded Nystagmus Acuity Function (NAFX) to measure tenotomy-induced changes in the nystagmus at primary position and various gaze angles. The longest foveation domains (LFD) were measured from fitted curves. Peak-to-peak nystagmus amplitudes and foveation-period durations were also measured. All measurements were made unmasked. Results: All seven patients with narrow, high-NAFX, gaze-angle regions showed broadening of these regions of higher visual function. Three patients showed moderate NAFX improvement (13.9-32.6%) at primary position, five showed large improvement (39.9-162.4%), and one showed no NAFX change (due to his high pretenotomy NAFX). Primary position measured acuities improved in six patients. All patients had reductions in nystagmus amplitudes ranging from 14.6 to 37%. The duration of the foveation period increased in all nine patients (11.2-200%). The percentage improvements in both the NAFX and the LFD decreased with higher pretenotomy values. Conclusions: In addition to elevating primary position NAFX, tenotomy also broadens the high-NAFX regions. This broadening effect is more prominent in patients who had sharp pretenotomy NAFX peaks. Four-muscle tenotomy produces higher primary position NAFX increases in infantile nystagmus patients whose pretenotomy values are relatively low, with the improvement decreasing at higher pretenotomy values. The tenotomy procedure improves visual function beyond primary position acuity. This extends the utility of surgical therapy to several different classes of patients with INS for whom other procedures are contraindicated. The pretenotomy NAFX can now be used to predict both primary position acuity improvements and broadening of a patient's high-NAFX range of gaze angles. © 2006 American Association for Pediatric Ophthalmology and Strabismus. |
T. Shery; Frank A. Proudlock; N. Sarvananthan; Rebecca J. McLean; Irene Gottlob The effects of gabapentin and memantine in acquired and congenital nystagmus: A retrospective study Journal Article In: British Journal of Ophthalmology, vol. 90, no. 7, pp. 839–843, 2006. @article{Shery2006, Background: Pharmacological treatment has been successful in some forms of acquired neurological nystagmus. However, drugs are not known to be effective in idiopathic infantile nystagmus or nystagmus associated with ocular diseases. Methods: The authors retrospectively analysed Snellen visual acuity (VA), subjective visual function, and eye movement recordings of 23 patients with nystagmus (13 secondary to multiple sclerosis, three associated with other neurological diseases, two idiopathic infantile, and five with associated ocular diseases) treated with gabapentin or memantine. Results: With gabapentin, 10 of 13 patients with nystagmus secondary to multiple sclerosis (MS) showed some improvement. Memantine improved the VA in all three patients with MS who did not improve on gabapentin. There was no change of nystagmus in other neurological disorders. Patients with congenital nystagmus showed reduction of nystagmus and their VA changes depended on the ocular pathology. Conclusion: Gabapentin and memantine may be effective in acquired nystagmus secondary to MS. To the authors' knowledge this is the first series of patients showing that gabapentin is effective in improving nystagmus in congenital nystagmus/nystagmus associated with ocular pathology. Memantine may be useful as an alternative drug in treating patients with nystagmus. |
2005 |
Andreas Sprenger; Elisabeth Zils; Holger Rambold; Thurid Sander; Christoph Helmchen Effect of 3,4-diaminopyridine on the postural control in patients with downbeat nystagmus Journal Article In: Annals of the New York Academy of Sciences, vol. 1039, pp. 395–403, 2005. @article{Sprenger2005, Downbeat nystagmus (DBN) is a common, usually persistent ocular motor sign in vestibulocerebellar midline lesions. Postural imbalance in DBN may increase on lateral gaze when downbeat nystagmus increases. 3,4-Diaminopyridine (3,4-DAP) has been shown to suppress the slow-phase velocity component of downbeat nystagmus and its gravity-dependent component with concomitant improvement of oscillopsia. Because the pharmacological effect is thought to be caused by improvement of the vestibulocerebellar Purkinje cell activity, the effect of 3,4-DAP on the postural control of patients with downbeat nystagmus syndrome was examined. Eye movements were recorded with the video-based Eyelink II system. Postural sway and pathway were assessed by posturography in lateral gaze in the light and on eye closure. Two out of four patients showed an improvement of the area of postural sway by 57% of control (baseline) on eye closure. In contrast, downbeat nystagmus in gaze straight ahead and on lateral gaze did not benefit in these two patients, implying a specific influence of 3,4-DAP on the vestibulocerebellar control of posture. It was concluded that 3,4-DAP may particularly influence the postural performance in patients with downbeat nystagmus. |