Pursuit Eye Movements Research Articles

Evaluation of Saccadic Component Measure on Smooth Pursuit Tests.

Despite the advancement of eye-tracking technology for smooth pursuit (SP) eye movement evaluation, qualitative observation offers much information that is not captured by computers; hence, both objective and qualitative information should be utilized to evaluate SP. This study examined the consistency among our clinicians when evaluating SP using normal (N), grossly normal (GN), mildly abnormal (MA), and abnormal (AB) as classifications. We then evaluated the effect of combining GN and MA into a single subclinical (SUBC) category. We also evaluated the computerized percent saccade (PS) metric by determining its sensitivity and specificity in classifying SP. Retrospective horizontal and vertical SP test videos and numerical data for 70 participants were obtained from the Neuro Kinetics Neuro-Otologic Test Center and de-identified. From this, eye-tracking videos, time plots of eye-tracking positional data, and tables of SP eye-tracking performance data were generated for 0.1, 0.3, and 0.5 Hz in both horizontal and vertical planes, totaling 6 tests per subject. Three clinicians rated each subject's SP performance as N, GN, MA, or AB for a total of 6 ratings (3 frequencies, horizontal and vertical). This process was repeated using N, SUBC, and AB as rating categories. Clinicians also provided an overall SP rating for each plane as follows: AB if the results were abnormal for 2 or more frequencies tested. Alternatively, if fewer than 2 frequencies presented with a rating of AB, then an overall rating of MA, GN, or N was determined at the respective clinician's discretion. When the 3 clinicians were tasked with classifying SP videos using 4 clinical categories, fair overall agreement was demonstrated. However, when MA and GN categories were combined into an SUBC category, the overall agreement for the 3 clinicians improved slightly for both horizontal SP (HSP) and vertical SP (VSP). This pattern of agreement did not differ considerably when comparing HSP versus VSP, and good consistency and reliability was observed across clinicians. Again, inter-rater consistency was smaller for VSP versus HSP despite the reduction in clinical categories. Cut-off values were generated for the PS metric and demonstrated good specificity and sensitivity when they were exceeded for 2 or more frequencies in a particular plane when evaluating a subject's SP test.

Predictive posture stabilization before contact with moving objects: equivalence of smooth pursuit tracking and peripheral vision.

Postural stabilization is essential to effectively interact with our environment. Humans preemptively adjust their posture to counteract impending disturbances, such as those encountered during interactions with moving objects, a phenomenon known as anticipatory postural adjustments (APAs). APAs are thought to be influenced by predictive models that incorporate object motion via retinal motion and extraretinal signals. Building on our previous work that examined APAs in relation to the perceived momentum of moving objects, here we explored the impact of object motion within different visual field sectors on the human capacity to anticipate motion and prepare APAs for contact between virtual moving objects and the limb. Participants interacted with objects moving toward them under different gaze conditions. In one condition, participants fixated on either a central point (central fixation) or left-right of the moving object (peripheral fixation), whereas in another, they followed the moving object with smooth pursuit eye movements (SPEMs). We found that APAs had the smallest magnitude in the central fixation condition and that no notable differences in APAs were apparent between the SPEM and peripheral fixation conditions. This suggests that the visual system can accurately perceive motion of objects in peripheral vision for posture stabilization. Using Bayesian model averaging, we also evaluated the contribution of different gaze variables, such as eye velocity and gain (ratio of eye and object velocity) and showed that both eye velocity and gain signals were significant predictors of APAs. Taken together, our study underscores the roles of oculomotor signals in the modulation of APAs.NEW & NOTEWORTHY We show that the human visuomotor system can detect motion in peripheral vision and make anticipatory adjustments to posture before contact with moving objects, just as effectively as when the eye movement system tracks those objects with smooth pursuit eye movements. These findings pave the way for research into how age-induced changes in spatial vision, eye movements, and motion perception could affect the control of limb movements and postural stability during motion-mediated interactions with objects.

Evidence for an Association Between a pH-Dependent Potassium Channel, TWIK-1, and the Accuracy of Smooth Pursuit Eye Movements.

Within the healthy population there is a large variation in the ability to perform smooth pursuit eye movements. Our purpose was to investigate the genetic and physiological bases for this variation. We carried out a whole-genome association study, recording smooth pursuit movements for 1040 healthy volunteers by infrared oculography. The primary phenotypic measure was root mean square error (RMSE) of eye position relative to target position. Secondary measures were pursuit gain, frequency of catch-up saccades, and frequency of anticipatory saccades. Ten percent of participants, chosen randomly, were tested twice, giving estimates of test-retest reliability. No significant association was found with three genes previously identified as candidate genes for variation in smooth pursuit: DRD3, COMT, NRG1. A strong association (P = 3.55 × 10-11) was found between RMSE and chromosomal region 1q42.2. The most strongly associated marker (rs701232) lies in an intron of KCNK1, which encodes a two-pore-domain potassium ion channel TWIK-1 (or K2P1) that affects cell excitability. Each additional copy of the A allele decreased RMSE by 0.29 standard deviation. When a psychophysical test of visually perceived motion was used as a covariate in the regression analysis, the association with rs701232 did not weaken (P = 5.38 × 10-12). Variation in the sequence or the expression of the pH-dependent ion channel TWIK-1 is a likely source of variance in smooth pursuit. The variance associated with TWIK-1 appears not to arise from sensory mechanisms, because the use of a perceptual covariate left the association intact.

Gaze and attention: mechanisms underlying the therapeutic effect of optokinetic stimulation in spatial neglect

Left smooth pursuit eye movement training in response to large-field visual motion (optokinetic stimulation) has become a promising rehabilitation method in left spatial inattention or neglect. The mechanisms underlying the therapeutic effect, however, remain unknown. During optokinetic stimulation, there is an error in visual localization ahead of the line of sight. This could indicate a change in the brain’s estimate of one’s own direction of gaze. We hypothesized that optokinetic stimulation changes the brain’s estimate of gaze. Because this estimate is critical for coding the locus of attention in the visual space relative to the body and across sensory modalities, its change might underlie the change in spatial attention. Here, we report that in healthy participants optokinetic stimulation causes not only a directional bias in the proprioceptive signal from the extraocular muscles, but also a corresponding shift of the locus of attention. Both changes outlasted the period of stimulation. This result forms a step in investigating a causal link between the adaptation in the sensorimotor gaze signals and the recovery in spatial neglect.

Oculomotor atypicalities in motor neurone disease: a systematic review.

Cognitive dysfunction is commonplace in Motor Neurone Disease (MND). However, due to the prominent motor symptoms in MND, assessing patients' cognitive function through traditional cognitive assessments, which oftentimes require motoric responses, may become increasingly challenging as the disease progresses. Oculomotor pathways are apparently resistant to pathological degeneration in MND. As such, abnormalities in oculomotor functions, largely driven by cognitive processes such as saccades and smooth pursuit eye movement, may be reflective of frontotemporal cognitive deficits in MND. Thus, saccadic and smooth pursuit eye movements may prove to be ideal mechanistic markers of cognitive function in MND. To ascertain the utility of saccadic and smooth pursuit eye movements as markers of cognitive function in MND, this review summarizes the literature concerning saccadic and smooth pursuit eye movement task performance in people with MND. Of the 22 studies identified, noticeable patterns suggest that people with MND can be differentiated from controls based on antisaccade and smooth pursuit task performance, and thus the antisaccade task and smooth pursuit task may be potential candidates for markers of cognition in MND. However, further studies which ascertain the concordance between eye tracking measures and traditional measures of cognition are required before this assumption is extrapolated, and clinical recommendations are made. https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=376620, identifier CRD42023376620.

Smooth pursuit deficits impact dynamic visual acuity in macular degeneration.

Prior studies with large, highly visible targets report low smooth pursuit gains in individuals with macular degeneration (MD). We show that lower gains persist even when observers are pursuing a target that requires discrimination at the acuity limit. This low gain causes retinal slip, potentially leading to motion blur and target disappearance in the scotoma, which further compromise the visibility of moving object. In this study, we examine whether the characteristics of smooth pursuit (pursuit gain and placement of the fixational locus relative to the target) change when the task requires dynamic visual acuity. Using the scanning laser ophthalmoscope, we recorded smooth pursuit eye movements in 10 eyes of 6 MD participants and 7 eyes of 4 age-matched controls in response to leftward- or rightward-moving annular targets (O) that briefly (300 milliseconds) changed to a Landolt C at one of several time points during the pursuit trial. Participants were asked to pursue the target and indicate the direction of the C opening. Individuals with MD had lower pursuit gains and fewer saccades during the C presentation than during the O, compared with their age-matched peers. Further, pursuit gain, but not the distance of the retinal pursuit locus from the target, predicted task performance in the MD group. Our findings suggest that compromised pursuit gain in MD participants likely further compromises their dynamic visual acuity and thus ability to view moving targets.

Elevated Smooth Pursuit Gain in Collegiate Athletes with Sport-related Concussion Immediately Following Injury.

Although there is evidence that sport-related concussion (SRC) affects oculomotor function and perceptual ability, experiments are often poorly controlled and are not replicable. This study aims to test the hypothesis that there are decreased values when assessing oculomotor impairment indicating poorer performance in SRC patients. Fifteen DI athletes presenting with SRC (7 females, 8 males) and 15 student volunteers (CON) (12 females, 3 males) completed a dynamic visual acuity (DVA) task that involved answering the direction of a moving stimulus (Landolt C) while wearing a head-mounted binocular eye tracker. There were 120 trials total with 60 trials presenting at 30º per second and 60 presenting at 90º per second. Various eye movement measurements, including horizontal smooth pursuit eye movements (SPEM) gain and saccadic peak velocity, were analyzed between groups using univariate ANOVAs. Saccade count in SPEM trials, accuracy, and vision were analyzed using Kruskal-Wallis tests. There was no statistical difference in saccadic peak velocity: SRC = 414.7 42º/s, CON = 406.6 40.6º/s. A significant difference was found between SRC patients and healthy controls in horizontal SPEM gain (SRC = 0.9 0.04, CON = 0.86 0.03, F(1,28) = 7.243, P = 0.012) indicating that patients demonstrated compensatory eye movements when tracking the target. There were significantly more saccades in all SPEM trials (P = 0.001). SRCoculomotor deficits manifest as elevated horizontal SPEM gain when assessed within 48 hours of injury and compared to healthy controls within the same age range. SRC demonstrates altered oculomotor ability. While accurate in tracking a stimulus, SRC patients may conduct less controlled eye movements.

Evidence from comprehensive independent validation studies for smooth pursuit dysfunction as a sensorimotor biomarker for psychosis

Smooth pursuit eye movements are considered a well-established and quantifiable biomarker of sensorimotor function in psychosis research. Identifying psychotic syndromes on an individual level based on neurobiological markers is limited by heterogeneity and requires comprehensive external validation to avoid overestimation of prediction models. Here, we studied quantifiable sensorimotor measures derived from smooth pursuit eye movements in a large sample of psychosis probands (N = 674) and healthy controls (N = 305) using multivariate pattern analysis. Balanced accuracies of 64% for the prediction of psychosis status are in line with recent results from other large heterogenous psychiatric samples. They are confirmed by external validation in independent large samples including probands with (1) psychosis (N = 727) versus healthy controls (N = 292), (2) psychotic (N = 49) and non-psychotic bipolar disorder (N = 36), and (3) non-psychotic affective disorders (N = 119) and psychosis (N = 51) yielding accuracies of 65%, 66% and 58%, respectively, albeit slightly different psychosis syndromes. Our findings make a significant contribution to the identification of biologically defined profiles of heterogeneous psychosis syndromes on an individual level underlining the impact of sensorimotor dysfunction in psychosis.

Individual differences link sensory processing and motor control.

Research on saccadic and pursuit eye movements led to great advances in our understanding of sensorimotor processing and human behavior. However, studies often have focused on isolated saccadic and pursuit eye movements measured with respect to different sensory information (static vs. dynamic targets). Here, we leveraged interindividual differences across a carefully balanced combination of different tasks to demonstrate that critical links in the control of oculomotor behavior were previously missed. We observed correlations in eye movement behavior across tasks, but only when compared with the same sensory information (e.g., pursuit gain and accuracy of saccades to moving targets). Within the same task, the coordination of saccadic and pursuit eye movements was tailored to the strengths of the individual: observers with more accurate saccades to moving targets rely on them more to catch up with moving targets. Our results have profound implications for the theoretical understanding of sensorimotor processing for oculomotor control. They necessitate a reevaluation of previous data used to map brain circuits for saccadic and pursuit eye movements measured with different types of relevant sensory information. Additionally, they underscore the importance of moving beyond average observations to embrace individual differences as a rich source of information. These individual differences not only reveal the strengths and weaknesses of observers. When combined across different tasks, they allow insights about why observers behave differently in a given task. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Interactions between Saccades and Smooth Pursuit Eye Movements in Marmosets.

Animals use a combination of eye movements to track moving objects. These different eye movements need to be coordinated for successful tracking, requiring interactions between the systems involved. Here, we study the interaction between the saccadic and smooth pursuit eye movement systems in marmosets. Using a single-target pursuit task, we show that saccades cause an enhancement in pursuit following a saccade. Using a two-target pursuit task, we show that this enhancement in pursuit is selective toward the motion of the target selected by the saccade, irrespective of any biases in pursuit prior to the saccade. These experiments highlight the similarities in the functioning of saccadic and smooth pursuit eye movement systems across primates.

Clinical value of video oculomotor evaluation in the differential diagnosis of multiple system atrophy and Parkinson's disease.

Multiple system atrophy (MSA) is a neurodegenerative disease that progresses rapidly and has a poor prognosis. This study aimed to assess the value of video oculomotor evaluation (VOE) in the differential diagnosis of MSA and Parkinson's disease (PD). In total, 28 patients with MSA, 31 patients with PD, and 30 age- and sex-matched healthy controls (HC) were screened and included in this study. The evaluation consisted of a gaze-holding test, smooth pursuit eye movement (SPEM), random saccade, and optokinetic nystagmus (OKN). The MSA and PD groups had more abnormalities and decreased SPEM gain than the HC group (64.29%, 35.48%, 10%, p<.001). The SPEM gain in the MSA group was significantly lower than that in the PD group at specific frequencies. Patients with MSA and PD showed prolonged latencies in all saccade directions compared with those with HC. However, the two diseases had no significant differences in the saccade parameters. The OKN gain gradually decreased from the HC to the PD and the MSA groups (p<.05). Compared with the PD group, the gain in the MSA group was further decreased in the OKN test at 30°/s (Left, p=.010; Right p=.016). Receiver operating characteristic curves showed that the combination of oculomotor parameters with age and course of disease could aid in the differential diagnosis of patients with MSA and PD, with a sensitivity of 89.29% and a specificity of 70.97%. The combination of oculomotor parameters and clinical data may aid in the differential diagnosis of MSA and PD. Furthermore, VOE is vital in the identification of neurodegenerative diseases.

A CASE OF SENSORY ATAXIA AND ITS MANAGEMENT THROUGH PANCHAKARMA

Sensory ataxia is both a symptom and a sign in neurology. It is a form of ataxia (loss of coordination) caused not by cerebellar dysfunction but by loss of sensory input into the control of movement. Sensory ataxia is dis-tinguished from cerebellar ataxia by the presence of near-normal coordination when the patient visually observes the movement but marked worsening of coordination when the eyes are shut, indicating a positive Romberg's sign. Sensory ataxia also lacks the associated features of cerebellar ataxia, such as pendular tendon reflexes, scanning dysarthria, nystagmus and broken pursuit eye movements. Sensory ataxia can manifest in sensory large fibre peripheral neuropathies and conditions causing dysfunction of the spinal cord's dorsal columns due to vari-ous disorders: infectious, auto-immune, metabolic, toxic, vascular and hereditary diseases. There is no direct correlation to sensory ataxia in Ayurvedic classics; based on pathology, it is nearer to Kaphavrita vyana vata. Objectives--By considering sensory ataxia as Kaphavrita vyana vata, the present study has attempted to evalu-ate the efficiency of Ayurvedic formulation in the conservative management of sensory ataxia. Met hod-A case of sensory ataxia, initially patient was treated with Dashamoola kaya seka followed by Shastika shalipindasweda, followed by Balavarnakara niruha basti1 and Anuvasana basti with ksheera bala taila as per Kala Basti schedule (modified), followed by Shaman aushadhi. Result-Patient was observed for symptomatic improvement based on the questionnaire over graded signs &amp; symptoms, also observed for clinical examination before &amp; after treatment. Conclusion: The study has shown that conservative management of sensory ataxia can be managed effectively through the Ayurvedic principle and improve quality of life.

Recovery Process for Sports-Related Concussion Assessed with Precise Ocular Motility.

Ocular motility has been linked to Sports Concussion Assessment Tool 5 scores. However, the link between ocular motility changes and assessment result changes remains unclear. Hence, we investigated that potential link in patients with sports-related concussions. We retrospectively included participants aged≥18 years who were diagnosed with a sports-related concussion. They underwent smooth pursuit eye movement assessment for allocation to the good improvement (rate of fundamental frequency≥15%) or minor improvement (<15%) groups. Sports Concussion Assessment Tool 5 scores were determined at baseline and two weeks later, and score changes were compared between the groups. Thirteen men (mean±standard deviation age: 20.6±5.0 years) were included: eight (19.0±4.5 years) in the good improvement group and five (20.6±5.7 years) in the minor improvement group. Symptom number (median=2.0 vs. 0.0), symptom severity (median=22.0 vs. 3.0), single-leg stance (median=4.0 vs. 0.5), tandem stance (median=1.0 vs. 0.0), and total errors (median=5.0 vs. 0.5) were worse (all p<0.05) in the minor improvement group. Smooth pursuit eye movement improvements measured using eye-tracking technology was linked to symptom recovery in patients with sports-related concussions. Therefore, ocular motility may be an objective indicator of sports-related concussions. Future studies with more patients are needed to confirm these findings.

Human estimates of descending objects' motion are more accurate than those of ascending objects regardless of gravity information.

Humans can accurately estimate and track object motion, even if it accelerates. Research shows that humans exhibit superior estimation and tracking performance for descending (falling) than ascending (rising) objects. Previous studies presented ascending and descending targets along the gravitational and body axes in an upright posture. Thus, it is unclear whether humans rely on congruent information between the direction of the target motion and gravity or the direction of the target motion and longitudinal body axes. Two experiments were conducted to explore these possibilities. In Experiment 1, participants estimated the arrival time at a goal for both upward and downward motion of targets along the longitudinal body axis in the upright (both axes of target motion and gravity congruent) and supine (both axes incongruent) postures. In Experiment 2, smooth pursuit eye movements were assessed while tracking both targets in the same postures. Arrival time estimation and smooth pursuit eye movement performance were consistently more accurate for downward target motion than for upward motion, irrespective of posture. These findings suggest that the visual experience of seeing an object moving along an observer's leg side in everyday life may influence the ability to accurately estimate and track the descending object's motion.

Sensorimotor-linked reward modulates smooth pursuit eye movements in monkeys.

Reward is essential for shaping behavior. Using sensory cues to imply forthcoming rewards, previous studies have demonstrated powerful effects of rewards on behavior. Nevertheless, the impact of reward on the sensorimotor transformation, particularly when reward is linked to behavior remains uncertain. In this study, we investigated how reward modulates smooth pursuit eye movements in monkeys. Three distinct associations between reward and eye movements were conducted in independent blocks. Results indicated that reward increased eye velocity during the steady-state pursuit, rather than during the initiation. The influence depended on the particular association between behavior and reward: a faster eye velocity was linked with reward. Neither rewarding slower eye movements nor randomizing rewards had a significant effect on behavior. The findings support the existence of distinct mechanisms involved in the initiation and steady-state phases of pursuit, and contribute to a deeper understanding of how reward interacts with these two periods of pursuit.

Bayesian approaches to smooth pursuit of random dot kinematograms: effects of varying RDK noise and the predictability of RDK direction.

Smooth pursuit eye movements respond on the basis of both immediate and anticipated target motion, where anticipations may be derived from either memory or perceptual cues. To study the combined influence of both immediate sensory motion and anticipation, subjects pursued clear or noisy random dot kinematograms (RDKs) whose mean directions were chosen from Gaussian distributions with SDs = 10° (narrow prior) or 45° (wide prior). Pursuit directions were consistent with Bayesian theory in that transitions over time from dependence on the prior to near total dependence on immediate sensory motion (likelihood) took longer with the noisier RDKs and with the narrower, more reliable, prior. Results were fit to Bayesian models in which parameters representing the variability of the likelihood either were or were not constrained to be the same for both priors. The unconstrained model provided a statistically better fit, with the influence of the prior in the constrained model smaller than predicted from strict reliability-based weighting of prior and likelihood. Factors that may have contributed to this outcome include prior variability different from nominal values, low-level sensorimotor learning with the narrow prior, or departures of pursuit from strict adherence to reliability-based weighting. Although modifications of, or alternatives to, the normative Bayesian model will be required, these results, along with previous studies, suggest that Bayesian approaches are a promising framework to understand how pursuit combines immediate sensory motion, past history, and informative perceptual cues to accurately track the target motion that is most likely to occur in the immediate future.NEW & NOTEWORTHY Smooth pursuit eye movements respond on the basis of anticipated, as well as immediate, target motions. Bayesian models using reliability-based weighting of previous (prior) and immediate target motions (likelihood) accounted for many, but not all, aspects of pursuit of clear and noisy random dot kinematograms with different levels of predictability. Bayesian approaches may solve the long-standing problem of how pursuit combines immediate sensory motion and anticipation of future motion to configure an effective response.

Normative tDCS over V5 and FEF reveals practice-induced modulation of extraretinal smooth pursuit mechanisms, but no specific stimulation effect

The neural networks subserving smooth pursuit eye movements (SPEM) provide an ideal model for investigating the interaction of sensory processing and motor control during ongoing movements. To better understand core plasticity aspects of sensorimotor processing for SPEM, normative sham, anodal or cathodal transcranial direct current stimulation (tDCS) was applied over visual area V5 and frontal eye fields (FEF) in sixty healthy participants. The identical within-subject paradigm was used to assess SPEM modulations by practice. While no specific tDCS effects were revealed, within- and between-session practice effects indicate plasticity of top-down extraretinal mechanisms that mainly affect SPEM in the absence of visual input and during SPEM initiation. To explore the potential of tDCS effects, individual electric field simulations were computed based on calibrated finite element head models and individual functional localization of V5 and FEF location (using functional MRI) and orientation (using combined EEG/MEG) was conducted. Simulations revealed only limited electric field target intensities induced by the applied normative tDCS montages but indicate the potential efficacy of personalized tDCS for the modulation of SPEM. In sum, results indicate the potential susceptibility of extraretinal SPEM control to targeted external neuromodulation (e.g., personalized tDCS) and intrinsic learning protocols.

Recording and interpretation of ocular movements: saccades, smooth pursuit, and optokinetic nystagmus

The ultimate role of ocular movements is to keep the image of an object within the fovea and thereby prevent image slippage on the retina. Accurate evaluations of eye movements provide very useful information for understanding the functions of the oculomotor system and determining abnormalities therein. Such evaluations also play an important role in enabling accurate diagnoses by identifying the location of lesions and discriminating from other diseases. There are various types of ocular movements, and this article focuses on saccades, fast eye movements, smooth pursuit, and slow eye movements, which are the most important types of eye movements used in evaluations performed in clinical practice.

Concordant GRADE-3 Truncal Ataxia and Ocular Laterodeviation in Acute Medullary Stroke.

Background: Severe truncal ataxia associated with an inability to sit up without assistance (STA grade 3) is frequent in patients with central acute vestibular syndrome (AVS) involving the brainstem or cerebellum. When these patients have nystagmus, central HINTS excludes peripheral lesions; however, additional localization and lateralization signs are helpful, not only to resolve the peripheral versus central vestibular lesion dilemma, but to zero in on a precise lesion localization/lateralization to the lateral medulla, the most common ischemic lesion localization associated with an initially false-negative stroke MRI. Methods: This is a study of AVS patients with additional inclusion criteria: grades 2 or 3 ataxia with an eventual diagnosis of medullary stroke (MS), either involving the lateral medulla (LMS) or the medial medulla (MMS), and horizontal (h) gaze paralysis was the main exclusion criteria. All patients sat on the side of the bed or stretcher, with assistance if needed. A general neurologic examination followed in the sitting position, the testing protocol included the head impulse, spontaneous nystagmus, and skew deviation (HINTS) tests, followed by observation of the effect of brief 3-5 sec eyelid closure on ocular position, and saccade and pursuit eye movement tests. If they could sit, the protocol included the ability to stand with a wide base, then a narrow base, the Romberg test, and tandem gait. Radiographic lesion localization and horizontal gaze deviation concluded the protocol. Results: A total of 34 patients met the entry criteria, 34 MS (13 in the lateral medulla, 12 previously described, and 1 new patient), and 1 new MMS. Among them, n = 10/12 had grade 3 ataxia, and 3 (1 new patient) had grade 2 ataxia. In addition, overt ocular laterodeviation (OLD) was present in thirteen of them (35.3%). All OLD patients had gaze deviation and ipsilateral saccade and truncal lateropulsion, 1 medial medulla stroke patient had grade 3 truncal contrapulsion and contralateral hemiparesis without OLD, n = 20/21 patients with LMS without OLD had grade 3 truncal ataxia, and 1 had grade 2 truncal ataxia. Discussion: AVS patients with severe truncal ataxia (inability to sit without assistance) potentially have brainstem, cerebellum, or subcortical lesions. All patients had central HINTS; however, simultaneous direction-concordant STA 3 and OLD provided greater lateral medulla localization specificity, affecting the ipsilateral medulla. Future work to explore a practical posterior circulation stroke scale that includes HINTS, STA, and OLD will potentially select cases for thrombolysis even in the event of initially false-negative imaging.

The effect of online visual games on visual perception, oculomotor, and balance skills of children with developmental dyslexia during the COVID-19 pandemic.

To evaluate the effect of online visual games on the balance, visual perception, and oculomotor skills of children with developmental dyslexia during the COVID-19 pandemic. In this single-blind randomized clinical trial, 50 children with developmental dyslexia, aged 7 to 11years, were recruited from rehabilitation centers in Tehran, Iran, using a convenience sampling strategy. Participants were randomly divided into two groups: intervention (25) and control (25), with close matching based on sex, age, IQ, and type of disease. The interventions consisted of web-based online computer games focusing on visual perception and oculomotor skills. Outcome measures included the Test of Visual Perception Skills-Revised, the Pediatric Balance Scale, and videonystagmography. The Wechsler Intelligence Scale for Children-IV and the Reading and Dyslexia Test were used to evaluate IQ and reading skills, respectively. The intervention group exhibited significant post-intervention improvements in the Test of Visual Perception Skills-Revised, tracking gain, saccade latency, and saccade velocity scores (all P < 0.001). In contrast, the control group showed no significant differences in these tests in pre- and post-intervention (all P > 0.05). Notably, post-intervention comparisons between the groups revealed significant differences in smooth pursuit eye movements (P < 0.001), saccade latency (P = 0.027), and saccade velocity (P < 0.001). The Pediatric Balance Scale scores remained unchanged in both groups post-intervention (intervention: P = 0.317; control: P = 0.999). Game face validity was affirmed with impact scores above 1.5 for all items, suggesting that the games were straightforward, clear, and relevant. Online visual games enhanced oculomotor and visual perception skills in children with dyslexia but did not influence balance skills.