Oculomotor Performance Research Articles

Eye Movement Patterns in Russian-Speaking Adolescents with Differing Reading Comprehension Proficiency: Exploratory Scanpath Analysis

Previous research has indicated that individuals with varying levels of reading comprehension (often used as a proxy for general cognitive ability) employ distinct reading eye movement patterns. This exploratory eye-tracking study aimed to investigate the text-reading process in adolescents with differing reading comprehension, specifically examining how these differences manifest at the global eye movement level through scanpath analysis. Our findings revealed two distinct groups of scanpaths characterized by statistically significant differences in eye movement parameters. These groups were identified as “fast readers” and “slow readers”. Both groups exhibited similar oculomotor performance during the initial reading. However, significant differences emerged when they reread and revisited the text. Notably, these findings align with prior research conducted with different samples and languages, although discrepancies emerged in saccade amplitude and first-pass reading behavior. This study contributes to the understanding of how reading comprehension levels are reflected in global eye movement strategies among adolescents. However, limitations inherent in the experimental design, particularly the potential influence of the task on reading patterns, warrant further investigation. Future research should aim to explore these phenomena in more naturalistic reading settings, employing a design specifically tailored to capture the nuances of spontaneous reading behavior.

Can playing video games enhance reading skills through more efficient serial visual search mechanisms? Insights from an eye tracking study

ABSTRACT Reading disorders are associated with atypical top-down visual attention (VA) processes like reduced VA span and slower serial visual search (SVS). In contrast, expert action video game (AVG) players, known for their efficient top-down VA, exhibit improved reading abilities. It is unclear whether these benefits stem solely from AVGs or apply to other gaming experiences. To explore this, AVG players (AVGPs), players of genres excluding AVGs (VGPs), and non-players were evaluated on their VA span, and behavioural and oculomotor performance in SVS. VGPs, but not AVGPs, demonstrated enhanced performance and oculomotor behaviour in SVS compared to non-players, while both player groups showed a trend towards better VA span skills. Notably, reading-related skills were enhanced in the two player groups, but particularly more so in VGPs. These findings support the existence of potential benefits of playing video games different from classical AVGs for the development of top-down VA and reading-related abilities.

Cervical Spine Vibration Modifies Oculomotor Function in Young Adults with Traumatic Brain Injury

ObjectiveThe purpose of this study was to investigate if vibrational interference of spinal proprioception affects oculomotor function, visual attention and processing, and selective attention in individuals with mild traumatic brain injury (mTBI) compared to healthy age-matched controls. MethodsThis study was a parallel design, single-session intervention with 20 young adults with mTBI and 20 age-matched controls. Each completed a battery of computerized eye-tracking assessments (CEAs), including egocentric localization, fixational stability, smooth pursuit, saccades, Stroop, and the vestibulo-ocular reflex (VOR), and then had their cervical spine function (flexion-relaxation ratio) recorded at baseline. Spinal vibration (100 Hz) was applied to the cervical spine and the CEA battery was repeated. CEA outcomes were compared to baseline and between mTBI and control groups. ResultsFollowing cervical vibration, significant pre to post-differences were seen in both the mTBI and control group for egocentric localization, fixation stability, pursuit, saccades, Stroop, and VOR. At baseline, there was a significant difference between the mTBI and control groups across many CEA measures, with the mTBI group performing more poorly in egocentric localization, pursuit, saccades, Stroop, and VOR. The mTBI group also had a poorer flexion-relaxation ratio than the control group. ConclusionCervical spine vibration improved cognitive and oculomotor performance in the mTBI group for VOR, Stroop, and pursuit, but had mixed effects on the control group. These findings suggest that some optometric mTBI symptoms may result from spinal or proprioceptive dysfunction, as altering proprioceptive input appears to positively impact visual outcomes.

Impact of macular scotoma and tubular vision on oculomotor behavior and performance in visuospatial comparison tasks.

Our aim in this study was to understand how we perform visuospatial comparison tasks by analyzing ocular behavior and to examine how restrictions in macular or peripheral vision disturb ocular behavior and task performance. Two groups of 18 healthy participants with normal or corrected visual acuity performed visuospatial comparison tasks (computerized version of the elementary visuospatial perception [EVSP] test) (Pisella et al., 2013) with a gaze-contingent mask simulating either tubular vision (first group) or macular scotoma (second group). After these simulations of pathological conditions, all participants also performed the EVSP test in full view, enabling direct comparison of their oculomotor behavior and performance. In terms of oculomotor behavior, compared with the full view condition, alternation saccades between the two objects to compare were less numerous in the absence of peripheral vision, whereas the number of within-object exploration saccades decreased in the absence of macular vision. The absence of peripheral vision did not affect accuracy except for midline judgments, but the absence of central vision impaired accuracy across all visuospatial subtests. Besides confirming the crucial role of the macula for visuospatial comparison tasks, these experiments provided important insights into how sensory disorder modifies oculomotor behavior with or without consequences on performance accuracy.

Oculomotor Patterns in Children with Poor Reading Abilities Measured Using the Development Eye Movement Test.

Objectives: The main purpose of this work was to clinically assess the oculomotricity of one hundred Mexican children with poor reading skills but without any specific learning disorder. Methods: The D.E.M. psychometric test was used. Sex and age analyses of the ratio, type, horizontal and vertical performance, and errors were carried out. Results: Our data suggest that 84% of poor readers exhibit oculomotor difficulties. Sex did not significantly influence the results (p > 0.05), whereas age was associated with the horizontal (p = 0.04) and vertical (p = 0.29) performance, as well as the number of errors (p = 0.001). Omissions were the most prevalent error type. Conclusions: This research gives insights into the role of oculomotricity in children with poor reading skills. Our results suggest that oculomotor performance should be included in the evaluation protocol to assess poor readers to identify any influence of the visual system.

Abnormal Ocular Movement in the Early Stage of Multiple-System Atrophy With Predominant Parkinsonism Distinct From Parkinson's Disease.

The eye-movement examination can be applied as a noninvasive method to identify multiple-system atrophy (MSA). Few studies have investigated eye movements during the early stage of MSA with predominant parkinsonism (MSA-P). We aimed to determine the characteristic oculomotor changes in the early stage of MSA-P. We retrospectively selected 17 patients with MSA-P and 40 with Parkinson's disease (PD) with disease durations of less than 2 years, and 40 age-matched healthy controls (HCs). Oculomotor performance in the horizontal direction was measured in detail using videonystagmography. We found that the proportions of patients with MSA-P and PD exhibiting abnormal eye movements were 82.4% and 77.5%, respectively, which were significantly higher than that in the HCs (47.5%, p<0.05). Compared with HCs, patients with MSA-P presented significantly higher abnormal proportions of fixation and gaze-holding (17.6% vs. 0%), without-fixation (47.1% vs. 0%), prolonged latency in reflexive saccades (29.4% vs. 5.0%), memory-guided saccades (93.3% vs. 10.0%), and catch-up saccades in smooth-pursuit movement (SPM, 41.2% vs. 0) (all p<0.05). Compared with those with PD, patients with MSA-P presented a significantly higher proportion of catch-up saccades in SPM (41.2% vs. 2.5%, p<0.001). MSA-P presented the characteristic of catch-up saccades in SPM in the early stage, which may provide some value in differentiating MSA-P from PD.

Smooth Pursuit and Reflexive Saccade in Discriminating Multiple-System Atrophy With Predominant Parkinsonism From Parkinson's Disease.

Performing the differential diagnosis of Parkinson's disease (PD) and multiple-system atrophy of parkinsonian type (MSA-P) is challenging. The oculomotor performances of patients with PD and MSA-P were investigated to explore their potential role as a biomarker for this differentiation. Reflexive saccades and smooth pursuit were examined in 56 patients with PD and 34 with MSA-P in the off-medication state. Patients with PD and MSA-P had similar oculomotor abnormalities of prolonged and hypometric reflexive saccades. The incidence rates of decreased reflexive saccadic velocity and saccadic smooth pursuit were significantly higher in MSA-P than in PD (p<0.05 for both). Multiple logistic regression analysis indicated that slowed reflexive saccades (odds ratio [OR]=8.14, 95% confidence interval [CI]=1.45-45.5) and saccadic smooth pursuit (OR=5.27, 95% CI=1.24-22.43) were significantly related to MSA-P. The distinctive oculomotor abnormalities of saccadic smooth pursuit and slowed reflexive saccades in MSA-P may serve as useful biomarkers for discriminating MSA-P from PD.

Regional Brain Structure Mediates Age‐Related Decline in Eye Movement Control

AbstractBackgroundEye movements (EM) are considered potential biomarkers of neurodegeneration because they are altered in patients with neurodegenerative disease, including Alzheimer’s disease (AD). Alterations in EM control have also been observed in old age, with particularly strong age effects on saccadic latency, inhibitory errors in the antisaccade task, and smooth pursuit accuracy. The goal of our study was to characterize the neural pathways of age‐related changes in these EM outcomes.MethodThe analysis was based on 8,318 participants (aged 30 to 95 years) from the population‐based Rhineland Study. EMs were recorded using video‐based infrared oculography at 1,000 Hz. Volumes and thickness measures of selected brain structures were obtained using FreeSurfer from 3 Tesla T1‐weighted MR images. Relations of brain structure with EM outcomes were quantified using multivariable linear regression models. Brain structure variables were also analyzed as potential mediators in the relation between age and EM outcomes using causal mediation analysis under a counterfactual framework.ResultIn women, higher volume of the right thalamus and right globus pallidus was associated with lower antisaccade latency, whereas higher cortical thickness in the anterior cingulate cortex was associated with higher antisaccade latency. Higher cortical thickness in right supramarginal gyrus and right paracentral lobule and sulcus was associated with fewer antisaccade errors in women. There were no significant associations between regional brain structure and antisaccade performance in men. Higher cortical thickness in the right calcarine sulcus was associated with higher smooth pursuit velocity gain in both men and women. Additionally, individual brain structures mediated up to 11% of the age‐related decline in EM performance.ConclusionOur results support that EMs indeed reflect neurodegenerative processes as changes in brain structure partly account for age‐related decline in oculomotor performance. Relevant brain regions include both brain regions vulnerable to AD pathology and brain regions that are typically spared, suggesting that both “normal” age‐related and pathological mechanisms may be causative for decline in EM control. Our results highlight the importance of taking into account normal age‐related changes when considering EMs as early biomarkers for AD. Further work is needed to better distinguish normal age‐related changes from pathological change.

1 Neurocognitive Correlates of Oculomotor Performance among U.S. Military Personnel with Mild Traumatic Brain Injury

Objective:To examine neurocognitive correlates of oculomotor performance among U.S. military personnel with history of mild traumatic brain injury (mTBI).Participants and Methods:A series of studies (total n=356) were conducted to examine saccadic eye movements and manual button presses collected in response to attention stimuli, and to compare these findings to the results of standardized neuropsychological tests. Study 1 included n=27 with remote mTBI and n=54 controls who completed the Bethesda Eye and Attention Measure (BEAM), an eye tracking task that was designed to measure visual attention and executive function. In Study 2, n=51 with chronic mTBI and n=33 controls completed the Fusion n-Back task, an eye tracking task that was designed to assess the impact of working memory load on visual attention performance. Study 3 examined psychometric characteristics of BEAM among n=191 military personnel with remote mTBI. In all studies, participants completed eye tracking tasks, a structured TBI diagnostic interview, and a brief battery of standardized neuropsychological tests.Results:In Study 1, BEAM saccadic and manual metrics demonstrated strong reliability and high sensitivity to multiple cognitive cues designed to elicit spatial orienting, temporal alerting, executive interference, perceptual release (gap) and inhibition (n2p=.76, p&lt;.001). However, corresponding saccadic and manual measurements were weakly related to each other, and only manual (not saccadic) measurements were related to estimated verbal intelligence or years of education. Standardized neuropsychological measures did not differ between groups, but mTBI participants were more likely to be impaired on saccadic metrics than controls.In Study 2, Standardized cognitive measures and estimated premorbid intelligence were positively associated with all manual metrics from the Fusion n-Back test, but were not associated with mTBI history or with saccadic metrics. Fusion n-Back saccadic and manual metrics had strong reliability and complementary sensitivity to chronic mTBI, with combined predictive power of PPV=.78, NPV=.72, r2=.44 for classification of remote mild TBI vs. controls on the more cognitively-challenging 1-back task condition.In Study 3, BEAM metrics including manual RT latency and consistency, saccadic RT consistency, and saccadic inhibition errors showed consistent correlations with standardized measures of visual attention, processing speed, task switching, working memory, and executive functions. Hierarchical regressions showed that BEAM saccadic and manual metrics were independently predictive of cognitive test performance, above and beyond effects of demographic factors and clinical characteristics.Conclusions:Results demonstrated some surprising findings related to neurocognitive influences on oculomotor performance. While both saccadic and manual performance were strongly and similarly influenced by attention cues, these two modalities were only weakly correlated to one another. Additionally, manual metrics were more strongly and consistently related to standardized cognitive test performance and premorbid intelligence than saccadic metrics. However, saccadic metrics demonstrated superior sensitivity to remote/chronic mTBI relative to manual metrics and standardized neuropsychological measures. Overall, these results suggest that saccadic eye tracking measures may provide unique value in assessment of mTBI and neurocognitive functions that is complementary with more common forms of assessment relying upon somatomotor response modalities.

Distinctive visual tasks for characterizing mild cognitive impairment and dementia using oculomotor behavior.

One's eye movement (in response to visual tasks) provides a unique window into the cognitive processes and higher-order cognitive functions that become adversely affected in cases with cognitive decline, such as those mild cognitive impairment (MCI) and dementia. MCI is a transitional stage between normal aging and dementia. In the current work, we have focused on identifying visual tasks (such as horizontal and vertical Pro-saccade, Anti-saccade and Memory Guided Fixation tasks) that can differentiate individuals with MCI and dementia from their cognitively unimpaired healthy aging counterparts based on oculomotor Performance indices. In an attempt to identify the optimal combination of visual tasks that can be used to differentiate the participant groups, clustering was performed using the oculomotor Performance indices. Results of our study with a group of 60 cognitively unimpaired healthy aging individuals, a group with 60 individuals with MCI and a group with 60 individuals with dementia indicate that the horizontal and vertical Anti-saccade tasks provided the optimal combination that could differentiate individuals with MCI and dementia from their cognitively unimpaired healthy aging counterparts with clustering accuracy of ∼92% based on the saccade latencies. Also, the saccade latencies during both of these Anti-saccade tasks were found to strongly correlate with the Neuropsychological test scores. This suggests that the Anti-saccade tasks can hold promise in clinical practice for professionals working with individuals with MCI and dementia.

Relationship between autonomic arousal and attention orienting in children and adolescents with ADHD, autism and co-occurring ADHD and autism

IntroductionAttention-Deficit/Hyperactivity Disorder (ADHD) and Autism Spectrum Disorder (ASD) may be characterized by different profiles of visual attention orienting. However, there are also many inconsistent findings emerging from the literature, probably due to the fact that the potential effect of autonomic arousal (which has been proposed to be dysregulated in these conditions) on oculomotor performance has not been investigated before. Moreover, it is not known how visual attention orienting is affected by the co-occurrence of ADHD and autism in people with a double diagnosis. Methods99 children/adolescents with or without ADHD and/or autism (age 10.79 ± 2.05 years, 65% boys) completed an adapted version of the gap-overlap task (with baseline and overlap trials only). The social salience and modality of stimuli were manipulated between trials. Eye movements and pupil size were recorded. We compared saccadic reaction times (SRTs) between diagnostic groups and investigated if a trial-by-trial association existed between pre-saccadic pupil size and SRTs. ResultsFaster orienting (shorter SRT) was found for baseline compared to overlap trials, faces compared to non-face stimuli and–more evidently in children without ADHD and/or autism–for multi-modal compared to uni-modal stimuli. We also found a linear negative association between pre-saccadic pupil size and SRTs, in autistic participants (without ADHD), and a quadratic association in children with ADHD (without autism), for which SRTs were slower when intra-individual pre-saccadic pupil size was smallest or largest. ConclusionOur findings are in line with previous literature and indicate a possible effect of dysregulated autonomic arousal on oculomotor mechanisms in autism and ADHD, which should be further investigated in future research studies with larger samples, to reliably investigate possible differences between children with single and dual diagnoses.

Istradefylline Improves Impaired Smooth Pursuit Eye Movements in Parkinson's Disease.

Patients with Parkinson's disease (PD) exhibit alterations in eye movement control, primarily diverse oculomotor deficits which include hypometric saccade and impaired smooth pursuit with reduced pursuit-gain necessitating catch-up saccades. The effects of dopaminergic treatment of PD on eye movements are controversial. Previous studies suggest that smooth pursuit eye movements (SPEMs) are not directly influenced by the dopaminergic system. The nondopaminergic drug istradefylline, a selective adenosine A2A receptor antagonist, reduces the OFF time and improves somatomotor function in levodopa-treated PD. Here, we investigated whether istradefylline improves SPEMs in PD, and determined whether oculomotor performance is associated with somatomotor performance. Using an infrared video eye tracking system, we quantified horizontal SPEMs in six patients with PD before and 4-8weeks after initiation of istradefylline administration. A further five patients with PD were tested before and after a 4-week interval without istradefylline to control for practice effects. We evaluated smooth pursuit gain (eye velocity/target velocity), accuracy of smooth pursuit velocity, and saccade rate during pursuitbefore and after istradefylline administration during the ON state. Patients received istradefylline by single daily oral administration at 20 to 40mg. Eye tracking data were obtained 4-8weeks after initiation of istradefylline administration. Istradefylline increased smooth pursuit gain and the accuracy of smooth pursuit velocity, and tended to decrease saccade rates during pursuit. Istradefylline ameliorated the oculomotor deficit in SPEM of patients with PD, although differences in somatomotor performance before and after istradefylline treatment were not significant during ON periods. The discrepancy observed between the oculomotor and somatomotor responses to istradefylline supports previous findings that SPEM is at least partially under nondopaminergic control.

Impact of depression and post-traumatic stress on manual and oculomotor performance in service members with a history of mild TBI

ABSTRACT Objective To determine the impact of depression and post-traumatic stress on an automated oculomotor and manual measure of visual attention, compared to conventional neuropsychological assessment. Setting: Military traumatic brain injury (TBI) rehabilitation program. Participants 188 Active Duty Service Members (ADSM) with a history of mild TBI. Design A cross-sectional and correlational study with data obtained through an IRB-approved data registry study. Main measures: Bethesda Eye & Attention Measure (BEAM); brief neuropsychological battery; self-reported symptom surveys including Neurobehavioral Symptom Inventory (NSI), Patient Health Questionnaire-8 (PHQ-8), and PTSD Checklist-5 (PCL-5). Results Small effect sizes were found for partial correlations between both depression and post-traumatic stress and key BEAM metrics. In contrast, small-to-medium effects sizes were found across all traditional neuropsychological test measures. Conclusion This study illustrates the profile of impairments associated with depression and post-traumatic stress on saccadic eye movements and manual responses to BEAM relative to conventional neuropsychological tests. Results demonstrated that among ADSM seen for mTBI, depression and PTS exert a significant negative impact on measures of processing speed, attention, executive function, and memory across saccadic, manual, and conventional neuropsychological tests. However, the unique psychometric features of each of these assessment approaches may assist in distinguishing the effects of psychiatric comorbidities within this population.

Structural and Functional Changes of Brain in Children With Intermittent Exotropia: A Study Combining Multiple MRI Modalities.

To investigate structural and functional changes of brain in children with intermittent exotropia (IXT) and their relationship with clinical features. Twenty-one IXT patients (mean age 9.38 ± 2.62 years) and 21 age-, gender-, education-, and handedness-matched healthy controls (HCs, mean age 9.52 ± 3.28 years) underwent high-resolution T1 imaging, diffusion tensor imaging (DTI), and resting-state functional MRI (rs-fMRI). The gray and white matter volume analyzed by voxel-based morphometry (VBM) based on T1 imaging, the fractional anisotropy (FA) and mean diffusivity (MD) indices based on DTI, and the amplitude of low frequency fluctuation (ALFF) value based on rs-fMRI were compared between these 2 groups. The correlations between MRI-derived parameters in significant brain regions and various clinical characteristics of IXT were analyzed. Compared with HCs, IXT children showed significantly decreased FA in right precentral gyrus (PRG) and right postcentral gyrus (POG), and significantly decreased ALFF in bilateral calcarine sulcus, bilateral cuneus, left lingual gyrus, and left superior occipital gyrus. The FA value in right PRG and right POG was negatively correlated with disease duration (r = -0.520, P = 0.016), angle of exodeviation at near (r = -0.549, P = 0.010), and angle of exodeviation at distance (r = -0.547, P = 0.010). IXT children exhibited abnormalities of white matter microstructure and reduced spontaneous neural activities in brain regions involving in oculomotor performance and binocular fusion. Further studies are needed to determine whether these findings are related to the neuropathologic mechanism or downstream changes of IXT.

Longitudinal Outcomes of Cumulative Impact Exposure on Oculomotor Functioning in Professional Motorsport Drivers

Professional motorsport drivers are regularly exposed to biomechanical forces comparable with those experienced by contact and collision sport athletes, and little is known about the potential short-term and long-term neurologic sequelae. To determine whether cumulative impact exposure is associated with oculomotor functioning in motorsport drivers from the INDYCAR professional open-wheel automobile racing series. This is a longitudinal retrospective cohort study conducted across 3 racing seasons (2017-2019). Statistical analyses were conducted in November 2021. Data were retrieved from a secondary care setting associated with the INDYCAR series. INDYCAR series drivers who participated in 3 professional level racing seasons and were involved in at least 1 contact incident (ie, crash) in 2 of the 3 seasons were included in the study. Cumulative acceleration and deceleration forces and total contact incidents (ie, crashes) measured via accident data recorder third generation chassis and ear accelerometers. Postseries oculomotor performance, including predictive saccades, vergence smooth pursuit, and optokinetic nystagmus, was measured annually with a head-mounted, clinical eye tracking system (Neurolign Dx 100). Thirteen drivers (mean [SD] age, 29.36 [7.82] years; all men) sustained median resultant acceleration forces of 38.15 g (observed range, 12.01-93.05 g; 95% CI, 30.62-65.81 g) across 81 crashes. A 2-way multivariate analysis of variance did not reveal a statistically significant association between ear and chassis average resultant g forces, total number of contact incidents, and racing season assessed (F9,12 = 0.955; P = .54; Wilks Λ = 0.44). In this cohort study of professional drivers from the INDYCAR series, there were no statistically significant associations among cumulative impact exposure, racing season assessed, and oculomotor performance. Longitudinal studies across racing seasons using multidimensional examination modalities (eg, neurocognitive testing, advanced imaging, biomarkers, and physical examination) are critical to understand potential neurological and neurobehavioral sequelae and long-term consequences of cumulative impact exposure.

Ocular motility as a measure of cerebral dysfunction in adults with focal epilepsy

ObjectiveUsing objective oculomotor measures, we aimed to: (1) compare oculomotor performance in patients with drug-resistant focal epilepsy to healthy controls, and (2) investigate the differential impact of epileptogenic focus laterality and location on oculomotor performance. MethodsWe recruited 51 adults with drug-resistant focal epilepsy from the Comprehensive Epilepsy Programs of two tertiary hospitals and 31 healthy controls to perform prosaccade and antisaccade tasks. Oculomotor variables of interest were latency, visuospatial accuracy, and antisaccade error rate. Linear mixed models were performed to compare interactions between groups (epilepsy, control) and oculomotor tasks, and between epilepsy subgroups and oculomotor tasks for each oculomotor variable. ResultsCompared to healthy controls, patients with drug-resistant focal epilepsy exhibited longer antisaccade latencies (mean difference = 42.8 ms, P = 0.001), poorer spatial accuracy for both prosaccade (mean difference = 0.4°, P = 0.002), and antisaccade tasks (mean difference = 2.1°, P < 0.001), and more antisaccade errors (mean difference = 12.6%, P < 0.001). In the epilepsy subgroup analysis, left-hemispheric epilepsy patients exhibited longer antisaccade latencies compared to controls (mean difference = 52.2 ms, P = 0.003), while right-hemispheric epilepsy was the most spatially inaccurate compared to controls (mean difference = 2.5°, P = 0.003). The temporal lobe epilepsy subgroup displayed longer antisaccade latencies compared to controls (mean difference = 47.6 ms, P = 0.005). SignificancePatients with drug-resistant focal epilepsy exhibit poor inhibitory control as evidenced by a high percentage of antisaccade errors, slower cognitive processing speed, and impaired visuospatial accuracy on oculomotor tasks. Patients with left-hemispheric epilepsy and temporal lobe epilepsy have markedly impaired processing speed. Overall, oculomotor tasks can be a useful tool to objectively quantify cerebral dysfunction in drug-resistant focal epilepsy.

Can masked gaze and arrow stimuli elicit overt orienting of attention? A registered report

Viewing an averted gaze can elicit saccades towards the corresponding location. Here, the automaticity of this gaze-following behaviour phenomenon was further tested by exploring whether such an effect can be detected in response to briefly-presented masked averted gazes. Participants completed an oculomotor interference task consisting of making leftward/rightward saccades according to a symbolic instruction cue. Crucially, either a task-irrelevant averted-gaze face or an arrow (i.e., a non-social control stimulus) was also presented in different blocks of trials. Faces and arrows were presented for either 1000 ms, or 8 ms and then backward-masked, to reduce the likelihood of conscious processing. Worse oculomotor performance emerged when the saccade direction did not match (vs match) that suggested by the task-irrelevant gaze/arrow stimuli in the unmasked condition. However, in the masked condition, no oculomotor interference occurred for any task-irrelevant stimulus. Results enrich knowledge about boundary conditions for gaze/arrow-driven orienting using ecological attention measures.

Oculomotor impairments in de novo Parkinson's disease.

Reliable electrophysiological indicators are urgently needed in the precise evaluation of Parkinson's disease (PD). It is still elusive whether oculomotor performance is impaired or has clinical value in early PD. This study aims to explore oculomotor performance in newly diagnosed, drug-naïve PD and its correlation with clinical phenotype. Seventy-five patients with de novo PD, 75 patients with essential tremor (ET), and 46 gender-and age-matched healthy controls (HCs) were included in this cross-sectional study. All subjects underwent oculomotor test via videonystagmography. Visually guided saccade latency, saccadic accuracy and gain in smooth pursuit eye movement (SPEM) at three frequencies of the horizontal axis were compared among the three groups. Patients with PD also received detailed motor and non-motor evaluation by serial scales. The association between key oculomotor parameters and clinical phenotypes were explored in PD patients. Both de novo PD and ET patients showed prolonged saccadic latency and decreased saccadic accuracy relative to HCs. SPEM gain in PD was uniformly reduced at each frequency. SPEM gain at 0.4 Hz was also decreased in ET compared with HCs. However, there was no significant difference of oculomotor parameters between de novo PD and ET patients. Furthermore, prolonged saccadic latency was correlated with long disease duration, whereas decreased SPEM gain was associated with severe motor symptoms in de novo PD patients. Ocular movements are impaired in de novo, drug naïve PD patients; these changes could be indicators for disease progression in PD.

Quantitative assessment of oculomotor function by videonystagmography in multiple system atrophy

ObjectiveTo quantitatively assess oculomotor impairments in multiple system atrophy (MSA) and to explore their correlation with clinical characteristics. MethodsWe recruited 45 patients with MSA, including 21 with dominant ataxia (MSA-C), 24 with dominant parkinsonism (MSA-P), and 40 age-matched healthy controls. Detailed oculomotor performance in the horizontal direction was measured using videonystagmography (VNG). ResultsWe found that the proportion of abnormal eye movements in patients with MSA was 93.3% (37.7%, 51.1%, 73.3%, 71.1%, and 37.8% on fixation and gaze-holding, without fixation, saccade, smooth pursuit, and optokinetic nystagmus tests, respectively). Patients with MSA-C showed significantly lower gains in smooth pursuit test and optokinetic nystagmus test, and a higher incidence of hypermetria in the saccade test than patients with MSA-P (all P < 0.05). No oculomotor deficits were correlated with age, age of onset, sex, disease duration, or Unified Multiple System Atrophy Rating Scale (USMARS) (all r < 0.25, P > 0.1). ConclusionsAn extremely high incidence of oculomotor impairments could be observed using VNG in both the MSA-C and MSA-P subtypes, although there were some differences between them. SignificanceA comprehensive oculomotor examination could serve as a valuable tool in the diagnostic workup of patients with MSA.

Normative Values of the Groffman Visual Tracing Test for the Assessment of Oculomotor Performance in the Adult Population.

The Groffman visual tracing (GVT) test is an indirect psychometric measure of oculomotor performance, used for the clinical assessment of eye movements. The test consists of two cards with five contorted lines of increasing overlap, crowding, and difficulty. The task starts from each of the letters at the top of the page, follows the line from the letter to the corresponding number at the bottom of the page, and the number is named. Although the GVT test was developed for the evaluation of children, it has also been applied to adults with visual and cognitive deficits. However, it lacks reference values. Therefore, the aim of the study was to assess oculomotor behavior across the typical human lifespan and to define normative data in an adult population. A total of 526 adults aged between 20 and 79 years, all without neurological or psychiatric deficits, were enrolled in the study. The results were analyzed by considering the accuracy and execution times separately. An influence of age, education and sex for accuracy was found, and age for the execution times was found. Norms for adults were developed considering the specific structure of the test and the accuracy and the execution time separately. The GVT test can now be applied in healthy and neurological adult populations for the evaluation of oculomotor performance.