Video-oculography Research Articles

Sickness and peripheral dizziness: A review

In this lecture, some aspects of vestibular pathology propedeutics are highlighted. The necessity of careful vestibulosensory reactions analysis by different physicians (ENT specialist, neurologist, internist, general practitioner) is emphasized. Main patients’ complaints (vertigo and unsteadiness) are distinguished between. Special attention is paid to the classification of these vestibulosensory reactions on their duration and periodicity. The terms (sickness itself and balance disorders that may be concomitant symptoms of kinetosis) are clearly defined. Theories and clinical manifestations of sickness syndromes and motion sickness are described in details. Clinical variants of peripheral and central vestibular dysfunction are analyzed. The importance of computerized technics of vestibulometry (electrooculography, video oculography and computer dynamic posturography) in order to make a topic diagnosis of vestibular dysfunction and to assess visual-vestibular interaction in sickness is emphasized.

Clinical and Video-Oculographic Characteristics of Spinocerebellar Ataxia Type 27B (GAA-FGF14 Ataxia): A Single-Center Retrospective Study

An intronic GAA repeat expansion in the FGF14 gene was recently identified as a common cause of autosomal dominant GAA-FGF14 ataxia (SCA27B). We aimed to characterize in detail the clinical and video-oculographic features in our cohort of SCA27B patients. We genotyped the FGF14 GAA repeat expansion in 52 patients with unsolved late-onset cerebellar ataxia. Brain MRI and nerve conduction study, as well as video-oculographic (VOG) assessment, were performed. Eight patients (15.4%) with pathogenic GAA repeat expansion in the FGF14 gene were found. The median age at onset was 51 years (range—23–63 years). Sensory axonal neuropathy was found in 5/8 patients. Cerebellar atrophy was observed in 5/8 patients, and in one case, pontocerebellar atrophy was found. All tested patients had impaired smooth pursuit, 5/6 patients had impaired vestibulo-ocular reflex suppression, nystagmus, and an increased number of square wave jerks, 4/6 patients had horizontal gaze-evoked nystagmus, 3/6 had spontaneous downbeat nystagmus, and 1/6 had an upbeat one. Video head impulse test gain was lower than 0.8 on both sides in 2/4 patients, along with the presence of overt saccades. Further studies in different cohorts are needed to complete the phenotype of the FGF14-related disorders.

Systematic assessment of square-wave jerks in progressive supranuclear palsy: a video-oculographic study

BackgroundThe presence of frequent macro-square-wave jerks (SWJs) has been recently included in the diagnostic criteria for progressive supranuclear palsy (PSP). The aim of the current video-oculographic study was to systematically assess the presence and features of SWJs during a brief fixation task in PSP, in comparison with Parkinson’s disease (PD) patients and healthy controls (HC).MethodsThirty-eight PSP patients, 55 PD patients and 40 HC were enrolled in the study. All patients underwent a video-oculographic (VOG) examination including a 5-s fixation task, and the number, duration and amplitude of SWJs were recorded. The diagnostic performance of several SWJs parameters were then compared in distinguishing PSP from PD patients and controls.ResultsPSP patients showed a higher number and amplitude of SWJs compared to PD patients and controls. At least two SWJs within the 5-s fixation task were observed in 81.6% of PSP patients, 52.7% of PD patients and 25% of HC. The SWJs amplitude was the parameter showing the highest performances in distinguishing PSP from PD (AUC: 0.78) and HC (AUC: 0.88), outperforming the SWJ number and duration. The SWJ amplitude was larger in PSP-Richardson’s syndrome than in PSP-Parkinsonism patients, while no difference was found between PSP patients with different degrees of vertical ocular motor dysfunction.ConclusionsThis video-oculographic study provides robust evidence of larger SWJs number and amplitude in PSP than in PD patients, with some potential for differential diagnosis, supporting the inclusion of this ocular sign in PSP criteria.

Deep Learning-Based Nystagmus Detection for BPPV Diagnosis.

In this study, we propose a deep learning-based nystagmus detection algorithm using video oculography (VOG) data to diagnose benign paroxysmal positional vertigo (BPPV). Various deep learning architectures were utilized to develop and evaluate nystagmus detection models. Among the four deep learning architectures used in this study, the CNN1D model proposed as a nystagmus detection model demonstrated the best performance, exhibiting a sensitivity of 94.06 ± 0.78%, specificity of 86.39 ± 1.31%, precision of 91.34 ± 0.84%, accuracy of 91.02 ± 0.66%, and an F1-score of 92.68 ± 0.55%. These results indicate the high accuracy and generalizability of the proposed nystagmus diagnosis algorithm. In conclusion, this study validates the practicality of deep learning in diagnosing BPPV and offers avenues for numerous potential applications of deep learning in the medical diagnostic sector. The findings of this research underscore its importance in enhancing diagnostic accuracy and efficiency in healthcare.

Quantification of saccadic fatigability and diagnostic efficacy for myasthenia gravis.

The diagnostic challenge of myasthenia gravis (MG) is exacerbated by the variable efficacy of current testing methodologies, necessitating innovative approaches to accurately identify the condition. This study aimed to assess ocular muscle fatigue in patients with MG using video-oculography (VOG) by examining repetitive saccadic eye movements and comparing these metrics to those of healthy control participants. This prospective, cross-sectional study was conducted at a tertiary care center and involved 62 patients diagnosed with MG (48 with ocular MG and 14 with generalized MG) and a control group of 31 healthy individuals, matched for age and sex. The assessment involved recording saccadic eye movements within a ± 15° range, both horizontally and vertically, at a rate of 15 saccades per minute over a 5-min period, resulting in 75 cycles. Participants were afforded a 3-min rest interval between each set to mitigate cumulative fatigue. The primary outcome was the detection of oculomotor fatigue, assessed through changes in saccadic waveforms, range, peak velocity, latency, and the duration from onset to target, with a focus on comparing the second saccade against the average of the last five saccades. In the evaluation of repetitive saccadic movements, patients with MG exhibited a reduced saccadic range and a prolonged duration to reach the target, compared to healthy subjects. Furthermore, a significant elevation in the frequency of multistep saccades was observed among MG patients, with a marked rise observed over consecutive trials. Receiver operating characteristic (ROC) analysis revealed the discriminative performance of multistep saccade frequency, in conjunction with variations in saccadic range and duration from onset to target achievement between the second saccade and the mean of the final five saccades, as effective in distinguishing MG patients from healthy subjects. Although alterations in peak saccadic velocity and latency were less pronounced, they were nevertheless detectable. The utilization of VOG for repetitive saccadic testing in the diagnosis of MG has demonstrated considerable diagnostic precision. This methodology affords significant accuracy in evaluating ocular muscle fatigue in MG patients, providing class III evidence supportive of its clinical application.

Application of motor learning theory to teach the head impulse test to emergency medicine resident physicians.

The objective was to develop an innovative method of training emergency medicine (EM) resident physicians to perform the head impulse test (HIT) component of the HINTS (head impulse test, nystagmus, test of skew) examination using video-oculography (VOG) device feedback. Using principles from motor learning theory and Ericsson's framework for expertise, we developed a training innovation utilizing VOG device feedback to teach the degree (10°-20°) and velocity (>100°/s) of head turn required for the HIT. We assessed the technical ability of participants to perform the HIT using the VOG device, without feedback, to count the number of successful HITs out of 20 attempts before, immediately after, and 2 weeks after the training innovation. Participants rated their confidence on a 1 to 5 Likert scale before and 2 weeks after training. Most participants (11 of 14, 78%) were unable to perform even one successful HIT in 20 attempts before training despite brief verbal and visual instruction regarding the head turn parameters. However, most participants achieved more than one success, in fact, all with at least five successes, immediately after training (13 of 14, 93%) and again 2 weeks after training (nine of 11, 82%). The median (interquartile range) number of successful HITs was 0 (0, mean 0.79) during baseline testing, 7.5 (5.8) immediately after training, and 10 (8.0) 2 weeks after training (p < 0.01, Kruskal-Wallis). The median confidence rating increased from 1.5 (1) before baseline testing to 3 (1.5) after follow-up testing (p = 0.02, Mann-Whitney U). Prior to motor training, most participants failed to properly perform the HIT. Feedback training with VOG devices may facilitate development of the skills required to properly perform the HIT. Further study is needed to assess the ability to train the interpretive aspect of the HIT and other components of the HINTS examination.

Ocular Myasthenia Gravis: A Diagnosis With Video Oculography.

Ocular Myasthenia Gravis: A Diagnosis With Video Oculography.

Quantifying Induced Nystagmus Using a Smartphone Eye Tracking Application (EyePhone).

There are ≈5 million annual dizziness visits to US emergency departments, of which vestibular strokes account for over 250 000. The head impulse, nystagmus, and test of skew eye examination can accurately distinguish vestibular strokes from peripheral dizziness. However, the eye-movement signs are subtle, and lack of familiarity and difficulty with recognition of abnormal eye movements are significant barriers to widespread emergency department use. To break this barrier, we sought to assess the accuracy of EyePhone, our smartphone eye-tracking application, for quantifying nystagmus. We prospectively enrolled healthy volunteers and recorded the velocity of induced nystagmus using a smartphone eye-tracking application (EyePhone) and then compared the results with video oculography (VOG). Following a calibration protocol, the participants viewed optokinetic stimuli with incremental velocities (2-12 degrees/s) in 4 directions. We extracted slow phase velocities from EyePhone data in each direction and compared them with the corresponding slow phase velocities obtained by the VOG. Furthermore, we calculated the area under the receiver operating characteristic curve for nystagmus detection by EyePhone. We enrolled 10 volunteers (90% men) with an average age of 30.2±6 years. EyePhone-recorded slow phase velocities highly correlated with the VOG recordings (r=0.98 for horizontal and r=0.94 for vertical). The calibration significantly increased the slope of linear regression for horizontal and vertical slow phase velocities. Evaluating the EyePhone's performance using VOG data with a 2 degrees/s threshold showed an area under the receiver operating characteristic curve of 0.87 for horizontal and vertical nystagmus detection. We demonstrated that EyePhone could accurately detect and quantify optokinetic nystagmus, similar to the VOG goggles.

Effect of binocular vision during target shooting in archery.

This study aimed to evaluate the difference between binocular and monocular vision and eye movements during the competition using video-oculography (VOG). Experiment 1 included 14 participants to evaluate differences in arrow convergence. Then, seven participants in Experiment 1 were randomly selected and included in Experiment 2, which evaluated eye movements during archery using VOG. The target used an 80-cm waterproof target face and was set at a distance of 30 m. All players shot the target 36 times using their bows and arrows. Experiments 1 and 2 evaluated the distribution of arrows in each score and the number of focus points, respectively, between binocular and monocular conditions. The arrows, which include the area of 9 points, were significantly greater in the binocular condition (11.85 ± 5.04 shots) than in the monocular condition (9.36 ± 5.41 shots) in Experiment 1 (P = 0.047). The players focused on the target under both binocular and monocular conditions, although the players were switching off fixation between the target and shooting sight under the binocular condition in Experiment 2. These behaviors indicated that the players were trying to accurately shoot the target by exploring the distance between themselves and the target as a cue for depth perception.

Convolution Neural Network Based Prediction for Eye Gaze Estimation

Levels of progress in progress have truly made it possible to get various kinds of biometric information from individuals, enabling bases on assessment of human conditions in cure, auto prospering, advancing, and various zones. These evaluations have particularly featured eye improvement as a convincing marker with respect to human conditions, and assessment on its applications is adequately being pursued. The contraptions as of now for the most part used for assessing eye overhauls rely on the video-oculography (VOG) procedure, wherein the course of look is outlined by managing eye pictures crushed a camera. Applying convolutional neural network (ConvNet) to the getting ready of eye pictures has been seemed to enable exact and unprecedented look assessment. Ordinary picture overseeing, in any case, is begun on execution using a PC, making it difficult to finish consistent look. We hence propose another eye picture overseeing framework that cycles look assessment and event disclosure starting with one fulfillment then onto the accompanying using a self-governing engineered lightweight ConvNet. This paper evaluates the course of action of the proposed lightweight ConvNet, the frameworks for learning and appraisal used, and the proposed methodology's ability to meanwhile see look heading and event occasion using a truly unassuming memory and at lower computational complex nature than standard ways of thinking.

Comparative Analysis of Strabismus Measurement Using a Video Oculagraphy System and Alternate Prism Cover Test.

The aim of the study was to compare distance vision measurements obtained with video oculography (VOG) and an alternate prism cover test (APCT). Single-center, retrospective, and cross-sectional. Eighty-seven subjects with strabismus were included. All patients underwent an optometric examination. The measurement of strabismus in distance vision was performed with the best optical correction using the APCT and the VOG GazeLab. Subjects were divided according to the type of strabismus; 41 were esotropic and 46 were exotropic. The general comparison of APCT and VOG showed a mean difference of 0.60±2.74 prism diopters (Δ), not observing statistical differences between both methods ( P =0.059) and presenting a correlation of 0.976 ( P <0.001). Using APCT, the mean amount of esotropia for the group was 18.31±11.64 Δ and that of exotropia was 19.62±8.80 Δ. Compared with the VOG, the mean value of esotropia for the group was 18.65±11.65 Δ and that of exotropia was 19.48±8.62 Δ. The means are statistically different for the esotropia group ( P =0.005) but not for the exotropia group ( P =0.318). There was a high direct correlation between the methods of measurement for both the esotropic ( R =0.980; P <0.001) and exotropic patients ( R =0.975; P <0.001). Bland-Altman analysis shows a mean difference of 1.37±2.76 Δ for the esotropia patients and 0.31±2.66 Δ for the exotropic patients, respectively. This study demonstrated comparable results in measuring strabismus between VOG and APTC for esotropia and exotropia, with an excellent correlation between both methods and good agreement, especially in subjects with exotropia.

Automatic Video-Oculography System for Detection of Minimal Hepatic Encephalopathy Using Machine Learning Tools.

This article presents an automatic gaze-tracker system to assist in the detection of minimal hepatic encephalopathy by analyzing eye movements with machine learning tools. To record eye movements, we used video-oculography technology and developed automatic feature-extraction software as well as a machine learning algorithm to assist clinicians in the diagnosis. In order to validate the procedure, we selected a sample (n=47) of cirrhotic patients. Approximately half of them were diagnosed with minimal hepatic encephalopathy (MHE), a common neurological impairment in patients with liver disease. By using the actual gold standard, the Psychometric Hepatic Encephalopathy Score battery, PHES, patients were classified into two groups: cirrhotic patients with MHE and those without MHE. Eye movement tests were carried out on all participants. Using classical statistical concepts, we analyzed the significance of 150 eye movement features, and the most relevant (p-values ≤ 0.05) were selected for training machine learning algorithms. To summarize, while the PHES battery is a time-consuming exploration (between 25-40 min per patient), requiring expert training and not amenable to longitudinal analysis, the automatic video oculography is a simple test that takes between 7 and 10 min per patient and has a sensitivity and a specificity of 93%.

Comparing silent reading performance for single sentences and paragraphs: an eye movement-based analysis

ABSTRACT Clinical relevance Reading performance in clinical practice is commonly evaluated by reading ‘aloud’ and ‘as fast as possible’ single sentences. Assessing comprehensive silent reading performance using passages, composed of multiple sentences, is the preferred reading mode in real-life reading conditions. Background The purpose of this study was to compare eye movement-based silent reading performance for standardised short sentences and paragraphs. Methods A group of 15 young volunteers (age range: 22–36 years) read silently and comprehensively in two sessions: (a) a paragraph with continuous text and (b) standardised short sentences. Text print size was 0.4 logMAR (1.0 M at 40 cm distance). Eye movements during reading were recorded using video oculography (EyeLink II, SR Research Ltd). Data analysis included computation of reading speed, fixation duration, the number of fixations, saccadic amplitude and percentage of regressions. Moreover, frequency distributions of fixation durations were analysed with ex-Gaussian fittings. Results Repeatability coefficient in silent reading speed was found better for the paragraph (66 wpm) than for short sentences (88 wpm). The superiority in repeatability coefficient for the corresponding eye movement parameters, i.e. fixation duration (35 vs 73 ms), regressions (10.1 vs. 22.3%) and fixations per word (0.21 vs. 0.37 fpw), was even more pronounced. In addition, a statistically significant improvement with the paragraph was found in average fixation duration (19 ± 26 ms, p = 0.02), regressions (4.2 ± 7.0%, p = 0.04) and ex-Gaussian fixation parameter, τ (82 vs. 111 ms). No statistically significant difference was found between average reading speed with the paragraph (220 ± 59 wpm) and the short sentences (206 ± 57 wpm) (p = 0.11). Discussion Due to their superior repeatability, paragraphs are preferable to short sentences when evaluating silent comprehensive reading. The concurrent recording of eye movement parameters in silent reading further improves variability and could offer an efficient measure of reading performance and a reliable biomarker of visuo-motor function.

Prevalence of Horizontal Canal Variant in 3,975 Patients With Benign Paroxysmal Positional Vertigo: A Cross-sectional Study.

Current understanding based on older studies is that pc-BPPV is far more common than hc-BPPV. Such studies are limited by small sample sizes, and often the supine roll test for hc-BPPV is not performed. To better estimate the prevalence of hc-BPPV, we studied a large cross-section of patients with VOG-diagnosed BPPV. Using a cross-sectional study of patients with BPPV, we investigated patients referred to NeuroEquilibrium specialty clinics throughout India between January 1, 2021, and December 31, 2021. All patients were evaluated with video oculography (VOG) during positional tests, and all diagnoses were confirmed by a neurotologist and neurologist. Of 3,975 patients with VOG-confirmed and specialist-diagnosed BPPV (median age, 51 years; 56.6% women), pc-BPPV accounted for 1,901 (47.8%), hc-BPPV was seen in 1,842 (46.3%), and anterior canal BPPV was found in 28 (0.7%) patients. This study found that hc-BPPV is far more common than previously reported. It is important to perform the supine roll test in addition to the Dix-Hallpike in all patients suspected with BPPV. Better training to diagnose patients with BPPV and to accurately recognize the nystagmus pattern of hc-BPPV should be a priority.

Comparison of sensory fusion recovery in different types programming of liquid crystal glasses

Objective: to compare the effectiveness of new method of sensory fusion recovery in patients with personalized adjustment of the frequency of alternation of liquid crystal glasses (LCG) compared with the empirical selection of the frequency of alternation. Material and methods. The study included 39 patients with concomitant convergent strabismus with orthotropy and no sensory fusion after surgical treatment of strabismus, who were prescribed LCG. The glasses were programmed empirically at 2 Hz in 21 patients (empiric group), in 18 patients — using the developed formula for calculating the frequency of alternation of LCG (calculated group). The compared groups did not differ in gender, age, visual acuity, and other characteristics. Results. Recovery of sensory fusion occurred more often with LCG in calculated group (16 patients, 88.9%) than in empiric group (9 patients, 42.9%), the difference is highly reliable (p=0.001). Conclusions. Anew method for personalized selection of the frequency of alternating LCG using video oculography is more efficient than empirical programming for sensory fusion restoration in children after surgery for concomitant convergent strabismus.

Comparison of sensory fusion recovery in different types programming of liquid crystal glasses

Objective: to compare the effectiveness of new method of sensory fusion recovery in patients with personalized adjustment of the frequency of alternation of liquid crystal glasses (LCG) compared with the empirical selection of the frequency of alternation. Material and methods. The study included 39 patients with concomitant convergent strabismus with orthotropy and no sensory fusion after surgical treatment of strabismus, who were prescribed LCG. The glasses were programmed empirically at 2 Hz in 21 patients (empiric group), in 18 patients — using the developed formula for calculating the frequency of alternation of LCG (calculated group). The compared groups did not differ in gender, age, visual acuity, and other characteristics. Results. Recovery of sensory fusion occurred more often with LCG in calculated group (16 patients, 88.9%) than in empiric group (9 patients, 42.9%), the difference is highly reliable (p=0.001). Conclusions. Anew method for personalized selection of the frequency of alternating LCG using video oculography is more efficient than empirical programming for sensory fusion restoration in children after surgery for concomitant convergent strabismus.

Acute mixed vestibulopathy. History case from the vestibulologist practice. Case report

Patients with acute vestibulopathy are among the most uneasy (in terms of severity of symptoms) and challenging (in terms of determining the level of damage). At the same time, the methods of traditional otoneurological examination often do not allow to reveal the cause of unexpected balance disorders. In order to determine the degree of vestibular function decompensation and develop the tactic for the urgent treatment, Saint Petersburg Research Institute of Ear, Throat, Nose and Speech uses both screening methods included in the Vestibular Passport and computerized vestibulometry techniques. Methods of oculomotor and postural reactions assessment are described in details using the example of case history. The high diagnostic significance of the results of instrumental vestibulometry using the Frenzel glasses, foam pad, computer electrooculography, video oculography and computer dynamic posturography is demonstrated. The therapeutic tactics of managing a patient with acute mixed vestibulopathy is shown.

Ocular counter-roll during a Mŕnière’s attack: evidence of ictal utricle pathway imbalance using fundus photography (P3-9.004)

<h3>Objective:</h3> To call attention to unrecognized ictal vestibular manifestations of Mŕnière’s disease. <h3>Background:</h3> During Mŕnière’s disease (MD) attacks, static semicircular canal (SCC) asymmetry causes spontaneous nystagmus (ipsilesional when excitatory, and contralesional when inhibitory). Acute dynamic SCC dysfunction can cause an abnormal head impulse test (HIT, e.g., acute vestibular neuritis), although the HIT can be normal during a MD attack. Documentation of ictal otolith (utricle and saccule) dysfunction using vestibular evoked myogenic potentials (VEMPs) has rarely been reported. We describe the first case, to our knowledge, of a patient presenting with a Mŕnière’s attack in whom an ocular counter-roll (OCR, from static utricle pathway imbalance) was documented using fundus photography. <h3>Design/Methods:</h3> One case report of a patient with an OCR observed during a MD attack. <h3>Results:</h3> A 65-year-old man with known history of bilateral MD presented during a typical vertigo attack, and testing demonstrated: 1) Video-oculography (VOG) – spontaneous horizontal-torsional, unidirectional right beating nystagmus, following Alexander’s law; 2) Video HIT (vHIT) – low gain (0.49 where &lt;0.7 is considered abnormal) in the plane of the left horizontal SCC; 3) fundus photography – OCR with the top poles of both eyes rotated toward the left ear, in the absence of other features of the ocular tilt reaction (OTR, including OCR, head tilt, skew deviation). The HINTS exam (head impulse, nystagmus, test of skew) suggested a left peripheral vestibulopathy, and a Mŕnière’s attack was diagnosed given his history. Three weeks later testing was repeated while asymptomatic: 1) VOG – no nystagmus; 2) vHIT – normal horizontal SCC gain (0.73); 3) fundus photography – no OCR. For more, visit the NOVEL collection: https://collections.lib.utah.edu/ark:/87278/s6k97g27 <h3>Conclusions:</h3> Using a non-mydriatic fundus camera, we were able to document an ictal OCR in MD. Its presence suggested utricle pathway imbalance, offering insight into the labyrinthine structures that may be involved during a MD attack. <b>Disclosure:</b> Dr. Fracica has nothing to disclose. Dr. Gold has received personal compensation in the range of $500-$4,999 for serving as an Editor, Associate Editor, or Editorial Advisory Board Member for Springer .

Video-oculographic Differences between Parkinson Disease and Multiple System Atrophy (P9-11.016)

<h3>Objective:</h3> With video-oculography (VOG), this study aimed to explore and compare visually-guided and self-paced volitional saccades in Parkinson’s disease (PD) and multiple system atrophy (MSA). <h3>Background:</h3> Saccades, rapid eye movements, are divided into two distinct types: reflexive and voluntary. Reflexive saccades are proceeded after a visual, auditory or somatosensory stimulus, while voluntary saccades require internally-generated drive. Each saccade is presumed to require separate neural systems. The voluntary saccades are mediated through higher centers, including frontal eye fields and basal ganglia, in addition to superior colliculus. Saccades are one of the most useful eye movements in the evaluation of the movement disorders. Voluntary saccades have been poorly investigated in PD and MSA. <h3>Design/Methods:</h3> We investigated visually guided reflexive and memory guided voluntary saccades by video-oculography in 39 PD and 15 MSA patients. There were no differences for age, sex, and UPDRS motor scores between PD and MSA patients. Two saccades were recorded sequentially, using an infrared eye tracking system (SMI, South Korea). <h3>Results:</h3> Comparison of visually-guided reflexive saccades between PD and MSA patients showed no difference in accuracy and peak velocity. In self-paced volitional saccades, PD patients produced significantly longer mean accuracy than MSA patients. Pause at the left eccentric position was consistently longer in both PD and MSA, with no statistical group difference. Volitional saccadic velocity was significantly slower than reflexive saccadic velocity in both groups. Self-paced saccadic accuracy was higher than reflexive saccadic accuracy only in PD, with significant difference. MSA patients did not show significant differences of accuracy between two saccades, although mean accuracy tended to be decreased in volitional saccades paradigm. <h3>Conclusions:</h3> In both PD and MSA patients, saccadic eye movements driven by memory-guided voluntary effort had much slower velocity, compared to visually-guided reflexive saccades. PD patients showed hypermetric volitional saccades, meanwhile MSA groups had no difference in accuracy between two saccades. <b>Disclosure:</b> Ms. Kim has nothing to disclose. Dr. Kim has nothing to disclose. Dr. Kim has nothing to disclose. Dr. Chang has nothing to disclose. Kee Duk Park has nothing to disclose. Dr. Yun has nothing to disclose.

Static cervico-ocular reflex in healthy humans

Background Dynamic cervico- (COR) and vestibulo-ocular reflex (VOR) contribute to stabilise visual images in the retina. The gain in dynamic COR is small in healthy individuals but increases in patients with vestibular dysfunction. Conversely, static COR has not been directly observed in healthy individuals. Objectives To elucidate the presence of static COR and quantify it in normal individuals in the roll plane. Methods Eleven healthy participants were included in the study. Eye torsions were measured using video oculography to evaluate the static COR induced by lateral neck flexion during a head-upright-with-body-tilt position at 15°, 30°, and 45°. The ocular counterroll (OCR) was compared during whole-body and head tilts to assess the influence of static COR on OCR. Results Static COR was significantly observed as eye torsion in the direction opposite to the body tilt. The head tilt OCR was significantly smaller than the whole-body tilt OCR to the right side but not to the left side. Conclusion Static COR exists in healthy individuals and tends to show higher amplitude as neck flexion stimulation increases.