Oculomotor Measures Research Articles

Artificial intelligence-assisted oculo-gait measurements for cognitive impairment in cerebral small vessel disease.

Oculomotor and gait dysfunctions are closely associated with cognition. However, oculo-gait patterns and their correlation with cognition in cerebral small vessel disease (CSVD) remain unclear. Patients with CSVD from a hospital-based cohort (n = 194) and individuals with presumed early CSVD from a community-based cohort (n = 319) were included. Oculo-gait patterns were measured using the artificial intelligence (AI) -assisted 'EyeKnow' eye-tracking and 'ReadyGo' motor evaluation systems. Multivariable linear and logistic regression models were employed to investigate the association between the oculo-gait parameters and cognition. Anti-saccade accuracy, stride velocity, and swing velocity were significantly associated with cognition in both patients and community dwellers with CSVD, and could identify cognitive impairment in CSVD with moderate accuracy (area under the curve [AUC]: hospital cohort, 0.787; community cohort, 0.810) after adjusting for age and education. The evaluation of oculo-gait features (anti-saccade accuracy, stride velocity, and swing velocity) may help screen cognitive impairment in CSVD. Oculo-gait features (lower anti-saccade accuracy, stride velocity, and swing velocity) were associated with cognitive impairment in cerebral small vessel disease (CSVD). Logistic model integrating the oculo-gait features, age, and education level moderately distinguished cognitive status in CSVD. Artificial intelligence-assisted oculomotor and gait measurements provide quick and accurate evaluation in hospital and community settings.

Oculomotor and Vestibular Deficits in Friedreich Ataxia - Systematic Review and Meta-Analysis of Quantitative Measurements.

Disease-specific oculomotor assessments play a crucial role in the early diagnosis of hereditary cerebellar ataxias. Whereas several studies have reported on quantitative oculomotor and vestibular measurements in Friedreich's Ataxia (FRDA), the value of specific oculomotor paradigms remains unclear. We aimed to address this knowledge gap through a systematic literature review and providing disease-specific recommendations for a tailored set of eye-movement recordings in FRDA. MEDLINE and Embase were searched for studies reporting on quantitative oculomotor and/or vestibular measurements in FRDA-patients. Data on oculomotor and vestibular parameters were extracted and correlations with a range of clinical parameters were sought. Included studies (n = 17) reported on 185 patients. Abnormalities observed included the presence of saccadic intrusions (143/161) such as square-wave jerks (SWJ, 90/109) and ocular flutter (21/43), impaired eccentric gaze-holding (40/104), abnormal pursuit (81/93) and angular vestibulo-ocular reflex (aVOR) deficits (39/48). For visually-guided saccades (VGS), we frequently observed increases in saccade latency (27/38) and dysmetric saccades (71/93), whereas saccade velocity was more often preserved (37/43). Augmented anti-saccade (AS) latency, downbeat nystagmus and frequent macro-SWJ correlated with disease duration. Increased AS-latency and VGS-latency, frequent macro-SWJ, reduced aVOR-gain and augmented aVOR peak-latency correlated with disease severity. A broad range of oculomotor and vestibular deficits are documented in the literature. Impairments in pursuit, saccades and aVOR-responses are most commonly reported, and as such, should be prioritized as disease markers. Quantitative oculomotor testing in FRDA may facilitate early diagnosis and prove valuable in monitoring disease progression and treatment response.

Oculometric biomarkers of visuomotor deficits in clinically asymptomatic patients with systemic lupus erythematosus undergoing long-term hydroxychloroquine treatment.

This study examines a set of oculomotor measurements, or "oculometric" biomarkers, as potential early indicators of visual and visuomotor deficits due to retinal toxicity in asymptomatic Systemic Lupus Erythematosus (SLE) patients on long-term hydroxychloroquine (HCQ) treatment. The aim is to identify subclinical functional impairments that are otherwise undetectable by standard clinical tests and to link them to structural retinal changes. We measured oculomotor responses in a cohort of SLE patients on chronic HCQ therapy using a previously established behavioral task and analysis technique. We also examined the relationship between oculometrics, OCT measures of retinal thickness, and standard clinical perimetry measures of visual function in our patient group using Bivariate Pearson Correlation and a Linear Mixed-Effects Model (LMM). Significant visual and visuomotor deficits were found in 12 asymptomatic SLE patients on long-term HCQ therapy compared to a cohort of 17 age-matched healthy controls. Notably, six oculometrics were significantly different. The median initial pursuit acceleration was 22%, steady-state pursuit gain 16%, proportion smooth 7%, and target speed responsiveness 31% lower, while catch-up saccade amplitude was 46% and fixation error 46% larger. Excluding the two patients with diagnosed mild toxicity, four oculometrics, all but fixation error and proportion smooth, remained significantly impaired compared to controls. Across our population of 12 patients (24 retinae), we found that pursuit latency, initial acceleration, steady-state gain, and fixation error were linearly related to retinal thickness even when age was accounted for, while standard measures of clinical function (Mean Deviation and Pattern Standard Deviation) were not. Our data show that specific oculometrics are sensitive early biomarkers of functional deficits in SLE patients on HCQ that could be harnessed to assist in the early detection of HCQ-induced retinal toxicity and other visual pathologies, potentially providing early diagnostic value beyond standard visual field and OCT evaluations.

Aging impairs reactive attentional control but not proactive distractor inhibition.

Older adults tend to be more prone to distraction compared with young adults, and this age-related deficit has been attributed to a deficiency in inhibitory processing. However, recent findings challenge the notion that aging leads to global impairments in inhibition. To reconcile these mixed findings, we investigated how aging modulates multiple mechanisms of attentional control by tracking the timing and direction of eye movements. When engaged in feature-search mode and proactive distractor suppression, older adults made fewer first fixations to the target but inhibited the task-irrelevant salient distractor as effectively as did young adults. However, when engaged in singleton-search mode and required to reactively disengage from the distractor, older adults made significantly more first saccades toward the task-irrelevant salient distractor and showed increased fixation times in orienting to the target, longer dwell times on incorrect saccades, and increased saccadic reaction times compared with young adults. Our findings reveal that aging differently impairs attentional control depending on whether visual search requires proactive distractor suppression or reactive distractor disengagement. Furthermore, our oculomotor measures reveal both age-related deficits and age equivalence in various mechanisms of attention, including goal-directed orienting, selection history, disengagement, and distractor inhibition. These findings help explain why conclusions of age-related declines or age equivalence in mechanisms of attentional control are task specific and reveal that older adults do not exhibit global impairments in mechanisms of inhibition. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Метакогнитивные читательские стратегии: анализ данных самоотчета и глазодвигательного поведения российских школьников

<p>The paper presents the results of a study aimed to investigate the correlations between oculomotor reading behavior and self-report data of Russian high school students on their practice of using metacognitive strategies. It was found that high school students tended to use problem-solving reading strategies, while seldom using supportive reading strategies. Differences in the use of metacognitive strategies were found between schools that emphasized differently the development of reading competence in middle school. The findings suggested that there were differences in oculomotor measures across groups with varying levels of metacognitive strategy use. The paper outlines possible directions for further research on this topic.</p>

Eye movement function captured via an electronic tablet informs on cognition and disease severity in Parkinson’s disease

Studying the oculomotor system provides a unique window to assess brain health and function in various clinical populations. Although the use of detailed oculomotor parameters in clinical research has been limited due to the scalability of the required equipment, the development of novel tablet-based technologies has created opportunities for fast, easy, cost-effective, and reliable eye tracking. Oculomotor measures captured via a mobile tablet-based technology have previously been shown to reliably discriminate between Parkinson’s Disease (PD) patients and healthy controls. Here we further investigate the use of oculomotor measures from tablet-based eye-tracking to inform on various cognitive abilities and disease severity in PD patients. When combined using partial least square regression, the extracted oculomotor parameters can explain up to 71% of the variance in cognitive test scores (e.g. Trail Making Test). Moreover, using a receiver operating characteristics (ROC) analysis we show that eye-tracking parameters can be used in a support vector classifier to discriminate between individuals with mild PD from those with moderate PD (based on UPDRS cut-off scores) with an accuracy of 90%. Taken together, our findings highlight the potential usefulness of mobile tablet-based technology to rapidly scale eye-tracking use and usefulness in both research and clinical settings by informing on disease stage and cognitive outcomes.

Observational learning of threat-related attentional bias

ABSTRACT Attentional bias to threat has been almost exclusively examined after participants experienced repeated pairings between a conditioned stimulus (CS) and an aversive unconditioned stimulus (US). This study aimed to determine whether threat-related attentional capture can result from observational learning, when participants acquire knowledge of the aversive qualities of a stimulus without themselves experiencing aversive outcomes. Non-clinical young-adult participants (N = 38) first watched a video of an individual (the demonstrator) performing a Pavlovian conditioning task in which one colour was paired with shock (CS+) and another colour was neutral (CS−). They then carried out visual search for a shape-defined target. Oculomotor measures evidenced an attentional bias toward the CS+ colour, suggesting that threat-related attentional capture can ensue from observational learning. Exploratory analyses also revealed that this effect was positively correlated with empathy for the demonstrator. Our findings extend empirical and theoretical knowledge about threat-driven attention and provide valuable insights to better understand the formation of anxiety disorders.

Reading proficiency predicts spatial eye-movement control in the first and second language.

Research on first language (L1) reading has long since established the link between the proficiency of the reader and their efficiency in oculomotor control. More proficient readers make longer saccades and land closer to the word's center, which is a word's optimal viewing position, and make fewer refixations. Eye-tracking studies of second language (L2) reading have so far provided little evidence in this regard. This study analyzes spatial oculomotor measures in the Multilingual Eye-movement Corpus, which contains data on English text reading and its component skills from 543 participants representing 12 different L1s. Our analyses establish a strong role of proficiency in English, both for L1 and L2 readers of English. While most effects replicated ones observed in L1 reading, we also found that more proficient readers of English were less accurate in targeting optimal viewing positions. We link this finding to Fitts' law of motor control for aimed movements. This article discusses the theoretical implications of the novel findings for reading research. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Oculomotor randomness is higher in autistic children and increases with the severity of symptoms.

A variety of studies have suggested that at least some children with autism spectrum disorder (ASD) view the world differently. Differences in gaze patterns as measured by eye tracking have been demonstrated during visual exploration of images and natural viewing of movies with social content. Here we analyzed the temporal randomness of saccades and blinks during natural viewing of movies, inspired by a recent measure of "randomness" applied to micro-movements of the hand and head in ASD (Torres et al., 2013; Torres & Denisova, 2016). We analyzed a large eye-tracking dataset of 189 ASD and 41 typically developing (TD) children (1-11 years old) who watched three movie clips with social content, each repeated twice. We found that oculomotor measures of randomness, obtained from gamma parameters of inter-saccade intervals (ISI) and blink duration distributions, were significantly higher in the ASD group compared with the TD group and were correlated with the ADOS comparison score, reflecting increased "randomness" in more severe cases. Moreover, these measures of randomness decreased with age, as well as with higher cognitive scores in both groups and were consistent across repeated viewing of each movie clip. Highly "random" eye movements in ASD children could be associated with high "neural variability" or noise, poor sensory-motor control, or weak engagement with the movies. These findings could contribute to the future development of oculomotor biomarkers as part of an integrative diagnostic tool for ASD.

Using behavior and eye-fixations to detect feigned memory impairment.

Detecting invalid cognitive performance is an important clinical challenge in neuropsychological assessment. The aim of this study was to explore behavior and eye-fixations responses during the performance of a computerized version of the Test of Memory Malingering (TOMM-C) under standard vs. feigning conditions. TOMM-C with eye-tracking recording was performed by 60 healthy individuals (31 with standard instruction - SI; and 29 were instructed to feign memory impairment: 21 Naïve Simulators - NS and 8 Coached Simulators - CS) and 14 patients with Multiple Sclerosis (MS) and memory complaints performed. Number of correct responses, response time, number of fixations, and fixation time in old vs. new stimuli were recorded. Nonparametric tests were applied for group comparison. NS produced fewer correct responses and had longer response times in comparison to SI on all three trials. SI showed more fixations and longer fixation time on previously presented stimuli (i.e., familiarity preference) specially on Trial 1, whereas NS had more fixations and longer fixation time on new stimuli (i.e., novelty preference) specially in the Retention trial. MS patients produced longer response time and had a different fixation pattern than SI subjects. No behavioral or oculomotor difference was observed between NS and CS. Healthy simulators have a distinct behavioral and eye-fixation response pattern, reflecting a novelty preference. Oculomotor measures may be useful to detect exaggeration or fabrication of cognitive dysfunction. Though, its application in clinical populations may be limited.

Keep it real, keep it simple: the effects of icon characteristics on visual search

ABSTRACT Previous research examining how icons’ concreteness, visual complexity, and distinctiveness influence visual search performance have led to disagreements over which icon characteristic most affects behaviour. These icon characteristics are often poorly defined and interrelated, particularly concreteness. Accordingly, drawing strong inferences about the robustness of concreteness as a factor in search for visual icons is challenging. Here, we operationalised concreteness into three distinct levels: concrete icons were images of real-world objects, photorealistic icons were drawings of the object, and abstract icons were images with no conceptual information. Across two experiments, participants rated each icon on various icon characteristics (e.g. concreteness, visual complexity) to provide a ground truth for these factors and to validate our concreteness manipulation. In a separate study, naive participants performed a visual search task for a target icon. Oculomotor measures were utilised to elucidate how various icon characteristics affected search performance. Although we were unable to fully disassociate concreteness from visual complexity, we found that icons high in concreteness improved search performance, but as visual complexity increased, object identification became slower. This was largely demonstrated through increased verification times for complex targets. The present set of studies indicate that highly concrete and simple icons engender search benefits.

Delayed oculomotor response associates with optic neuritis in youth with demyelinating disorders

IntroductionImpairment in visual and cognitive functions occur in youth with demyelinating disorders such as multiple sclerosis, neuromyelitis optica spectrum disorder, and myelin oligodendrocyte glycoprotein antibody-associated disease. Quantitative behavioral assessment using eye-tracking and pupillometry can provide functional metrics for important prognostic and clinically relevant information at the bedside. MethodsChildren and adolescents diagnosed with demyelinating disorders and healthy, age-matched controls completed an interleaved pro- and anti-saccade task using video-based eye-tracking and underwent spectral-domain optical coherence tomography examination for evaluation of retinal nerve fiber layer and ganglion cell inner plexiform layer thickness. Low-contrast visual acuity and Symbol Digit Modalities Test were performed for visual and cognitive functional assessments. We assessed saccade and pupil parameters including saccade reaction time, direction error rate, pupil response latency, peak constriction time, and peak constriction and dilation velocities. Generalized Estimating Equations were used to examine the association of eye-tracking parameters with optic neuritis history, structural metrics, and visual and cognitive scores. ResultsThe study included 36 demyelinating disorders patients, aged 8–18 yrs. (75% F; median = 15.22 yrs., SD = 2.8) and 34 age-matched controls (65% F; median = 15.26 yrs., SD = 2.3). Surprisingly, pro- and anti-saccade performance was comparable between patients and controls, whereas pupil control was altered in patients. Oculomotor latency measures were strongly associated with the number of optic neuritis episodes, including saccade reaction time, pupil response latency, and peak constriction time. Peak constriction time was associated with both retinal nerve fiber layer and ganglion cell inner plexiform layer thickness. Pupil response latency and peak constriction time were associated with visual acuity. Pupil velocity for both constriction and dilation was associated with Symbol Digit Modalities Test scores. ConclusionThe strong associations between oculomotor measures with history of optic neuritis, structural, visual, and cognitive assessments in these cohorts demonstrates that quantitative eye-tracking can be useful for probing demyelinating injury of the brain and optic nerve. Future studies should evaluate their utility in discriminating between demyelinating disorders and tracking disease progression.

Concealed familiar face detection with oculomotor measures and EEG in rapid serial visual presentation

Concealed familiar face detection with oculomotor measures and EEG in rapid serial visual presentation

High-resolution eye-tracking via digital imaging of Purkinje reflections.

Reliably measuring eye movements and determining where the observer looks are fundamental needs in vision science. A classical approach to achieve high-resolution oculomotor measurements is the so-called dual Purkinje image (DPI) method, a technique that relies on the relative motion of the reflections generated by two distinct surfaces in the eye, the cornea and the back of the lens. This technique has been traditionally implemented in fragile and difficult to operate analog devices, which have remained exclusive use of specialized oculomotor laboratories. Here we describe progress on the development of a digital DPI, a system that builds on recent advances in digital imaging to enable fast, highly precise eye-tracking without the complications of previous analog devices. This system integrates an optical setup with no moving components with a digital imaging module and dedicated software on a fast processing unit. Data from both artificial and human eyes demonstrate subarcminute resolution at 1kHz. Furthermore, when coupled with previously developed gaze-contingent calibration methods, this system enables localization of the line of sight within a few arcminutes.

Parallel word reading revealed by fixation-related brain potentials

During reading, the brain is confronted with many relevant objects at once. But does lexical processing occur for multiple words simultaneously? Cognitive science has yet to answer this prominent question. Recently it has been argued that the issue warrants supplementing the field's traditional toolbox (response times, eye-tracking) with neuroscientific techniques (EEG, fMRI). Indeed, according to the OB1-reader model, upcoming words need not impact oculomotor behavior per se, but parallel processing of these words must nonetheless be reflected in neural activity. Here we combined eye-tracking with EEG, time-locking the neural window of interest to the fixation on target words in sentence reading. During these fixations, we manipulated the identity of the subsequent word so that it posed either a syntactically legal or illegal continuation of the sentence. In line with previous research, oculomotor measures were unaffected. Yet, syntax impacted brain potentials as early as 100 ms after the target fixation onset. Given the EEG literature on syntax processing, the presently observed timings suggest parallel word reading. We reckon that parallel word processing typifies reading, and that OB1-reader offers a good platform for theorizing about the reading brain.

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.

Baseline Computerized Neurocognitive Testing and Oculomotor Measures are not Altered by Hormonal Contraceptive Use.

Neurocognitive testing and oculomotor assessment have been an integral component to provide objective measures for sport-related concussion (SRC) detection and management. Hormonal contraceptive (HC) use is common among collegiate female athletes and may modify baseline SRC performance. The purpose was to examine the effects of HC use on baseline computerized neurocognitive testing (CNT) and oculomotor testing in college-aged individuals. A total of 63 participants (22 HC using females, 22 non-HC using females, 19 males) completed a baseline SRC battery consisting of CNT, near point of convergence (NPC), and the King-Devick (KD) test. CNT measures were composite scores of verbal and visual memory, visual motor processing speed and reaction time, impulse control, and cognitive efficiency index (CEI). NPC was measured as the average convergence distance across three trials. KD time was recorded as total time for each of the two trials and best trial marked as baseline. There were no group differences between HC, non-HC, and male control groups on all baseline CNT composite scores (p = .13-.98), impulse control (p = .47), and CEI (p = .49). NPC distance was similar between groups (p = .41), as well as KD time by trial (Trial 1 p = .65; 2 p = .48) and best time (p = .49). HC use does not appear to influence baseline SRC measures of neurocognition and oculomotor assessment. Clinicians should continue to consider the effects of modifying factors at baseline and post-concussion. Additional research is needed to better understand sex hormone levels and SRC performance measures.

High-resolution oculomotor measurements via a digital Dual Purkinje Image eye-tracker

High-resolution oculomotor measurements via a digital Dual Purkinje Image eye-tracker

Pupil and eye tracking measures as a tool for detection and intervention in neurodegeneration

AbstractBackgroundThe locus coeruleus–noradrenaline system plays an extensive role in cognition and behaviour. It is among the earliest and most prominent sites of pathology in neurodegenerative diseases of ageing, including Alzheimer’s and Parkinson’s disease. Improving our ability to detect changes in this system in vivo has implications for early diagnosis and for tracking treatment interventions.MethodMy talk will focus on pupil and oculomotor measures as a biomarker to detect changes in the locus coeruleus–noradrenaline system. I will discuss results from a study in Parkinson’s disease patients (N=19) who underwent a pharmacological challenge using the noradrenergic reuptake inhibitor atomoxetine (40mg). In this study, we characterised the locus coeruleus using ultra‐high‐field 7T MRI and tested patients on and off atomoxetine, using a suite of oculomotor eye tracking tasks and a learning task combined with pupillometry.ResultWe show that atomoxetine improves cognitive performance and saccadic reaction times. Crucially, atomoxetine led to larger pupil responses that varied as a function of locus coeruleus integrity.ConclusionTogether, these results show that pupil and eye tracking measures are an effective biomarker for the locus coeruleus–noradrenaline system, and they are sensitive to pharmacological interventions. I will discuss the implications of these results for early detection and monitoring of subcortical changes in Alzheimer’s disease.

Visual-Spatial Attentional Performance Identifies Lower Extremity Injury Risk in Adolescent Athletes.

Strategies to identify lower extremity musculoskeletal (LEMSK) injury risk have been informed by prospectively identified biomechanical and neuromuscular risk factors. Emergent evidence suggests that cognitive and oculomotor performance may also contribute to LEMSK injury. The purpose of this study was to determine whether prospective cognitive and oculomotor measures identify adolescent athletes who sustain an in-season LEMSK injury. Prospective longitudinal study. Controlled laboratory and athletic event settings. Four hundred eighty-eight adolescent male football and female soccer athletes aged 13 to 18 years. Preseason baseline cognitive and oculomotor performance: Attention Network Task (ANT), cued task switching, King-Devick test, and near point of convergence. Incidence of LEMSK sprains and strains during a single competitive season. Attention Network Task-orienting network reaction time (RT) was the only cognitive or oculomotor measure significantly associated with LEMSK injury [B = 1.015, 95% confidence interval (CI): 1.01-1.024, P < 0.01]. Every 10 milliseconds increase in orienting network RT was associated with a 15% increased risk for LEMSK injury. Athletes demonstrating an orienting network RT ≥ 32.8 milliseconds had a higher risk for LEMSK injury relative to athletes below the cut-point (relative risk, 2.62; 95% CI, 1.52-4.52; odds ratio, 3.00; 95% CI, 1.63-5.52). Deficits in visual-spatial components of attention were associated with 2.62 times greater risk for LEMSK injury in adolescent athletes. The present results add evidence to suggest that visual-spatial attentional processing contributes to LEMSK injury and may supplement previously established LEMSK injury risk assessments.