Gain of Slow-Phase Velocity of Optokinetic Nystagmus

Prolonged microgravity during orbital flight is a unique way to modify the otolith inputs and to determine the extent of their contribution to the vertical vestibulo-ocular reflex (VOR) and optokinetic nystagmus (OKN). This paper reviews the data collected on 10 astronauts during several space missions and focuses on the changes in the up-down asymmetry. Both the OKN elicited by vertical visual stimulation and the active VOR elicited by voluntary pitch head movements showed an asymmetry before flight, with upward slow phase velocity higher than downward slow phase velocity. Early in-flight, this asymmetry was inverted, and a symmetry of both responses was later observed. An upward shift in the vertical mean eye position in both OKN and VOR suggests that these effects may be related to otolith-dependent changes in eye position which, in themselves, affect slow phase eye velocity.

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Vertical Optokinetic Nystagmus and Optokinetic Afternystagmus in Humans

Journal of Vestibular Research ◽

10.3233/ves-1991-1309 ◽

1991 ◽

Vol 1 (3) ◽

pp. 309-315

Author(s):

A. Böhmer ◽

R.W. Baloh

Keyword(s):

Phase Velocity ◽

Optokinetic Nystagmus ◽

Body Position ◽

Normal Subjects ◽

Lateral Position ◽

Velocity Storage ◽

Slow Phase ◽

Lateral Side ◽

Slow Phase Velocity ◽

Optokinetic Afternystagmus

Vertical optokinetic nystagmus (OKN) and optokinetic afternystagmus (OKAN) were recorded in 6 normal subjects using the magnetic scleral search coil technique in order to reevaluate the up-down symmetry of these responses. The effects of body position relative to gravity were investigated by comparing OKN and OKAN elicited with the subjects in an erect and in a lateral side position. No consistent up-down asymmetry in vertical OKN was found but OKAN was asymmetric (up slow phase velocity > down slow phase velocity). Most subjects had an immediate reversal in OKAN slow phase velocity after downward stimuli. No significant effects of static head position (upright versus lateral position) on vertical OKN and OKAN were found. These features of human OKAN can be explained by the summation of two oppositely directed velocity storage mechanisms.

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Does habitual, vigorous optokinetic stimulation alter optokinetic nystagmus and sensitivity to circularvection?

Journal of Vestibular Research ◽

10.3233/ves-1999-9107 ◽

1999 ◽

Vol 9 (1) ◽

pp. 59-61

Author(s):

Kate H. McDermott ◽

Anna J. Matheson ◽

Nikoli Titov ◽

Cynthia L. Darlington ◽

Paul F. Smith

Keyword(s):

Phase Velocity ◽

Optokinetic Nystagmus ◽

Confounding Factor ◽

Practice Effects ◽

Slow Phase ◽

Optokinetic Stimulation ◽

Slow Phase Velocity ◽

Visual Vestibular Interaction ◽

Sporting Activities ◽

High Degree

Previous studies have shown that experience with optokinetic stimulation can alter a subject's sensitivity to illusions such as circularvection (CV). The aim of the present experiment was to compare optokinetic nystagmus (OKN), optokinetic afternystagmus (OKAN), and sensitivity to CV between 2 groups of sportspeople: 1) squash players (n=16), who regularly experience vigorous optokinetic stimulation while engaging in their sporting activity, and 2) weightlifters (n=16), whose sport does not involve the same degree of optokinetic stimulation as squash, but who nevertheless have to achieve a high degree of physical skill. OKN, OKAN (frequency, slow phase velocity, and timeconstant), and latency to CV (Stage 2 and Stage 3) were measured using electro-oculographic recording inside an optokinetic drum. Contrary to predictions,there were no significant differences in OKN, OKAN, or latency to CV between the 2 groups. These results suggest that 1) the practice effects that alter the sensitivity to CV may decay relatively quickly, and 2) differences in recreational sporting activities between subjects may not be a significant confounding factor in visual-vestibular interaction experiments.

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Measurement of Optokinetic Nystagmus for Otoneurological Diagnosis

Annals of Otology Rhinology & Laryngology ◽

10.1177/00034894810901s201 ◽

1981 ◽

Vol 90 (1_suppl2) ◽

pp. 1-12 ◽

Cited By ~ 8

Author(s):

Sharon M. Abel ◽

Hugh O. Barber

Keyword(s):

Phase Velocity ◽

Optokinetic Nystagmus ◽

Normal Subjects ◽

Error Rates ◽

Slow Phase ◽

Brainstem Lesion ◽

Black And White ◽

Slow Phase Velocity ◽

Unilateral Labyrinthectomy ◽

The Difference

Optokinetic nystagmus was recorded and measured in 101 subjects comprising six diagnostic categories: 1) normal, screened for otologic disease, 2) chronic unilateral labyrinthectomy, 3) unilateral Menière's disease, 4) neurologically confirmed focal brainstem lesion, 5) brainstem-cerebellar syndrome, and 6) focal unilateral supratentorial lesion. For the OKN test, each subject looked at a translucent screen onto which a field of parallel black and white bars was back-projected. The array of bars could be projected vertically or horizontally to allow for study of nystagmus beating right and left or up and down. The speed of movement of the bars varied over a range from 20 to 140°/sec of visual angle, in each axis for both directions. An analysis of the slow phase velocity of OKN indicated that patients with brainstem disease produced significantly lower eye speeds than did normal subjects or patients with chronic peripheral vestibular disease. The latter groups could not be distinguished. The responses of patients with cortical lesions fell midway between these two extremes and were significantly different from those of the brainstem group. Directional preponderance of nystagmus proved to be significantly related to the side of lesion for both the labyrinthine and cortical groups. However, the absolute value of the difference in slow phase velocity for nystagmus beating toward or away from the side of lesion was no greater than the difference between right and left-beating nystagmus in normal subjects. While the results provide statistical confirmation for the findings of earlier investigations, it is noted that for purposes of clinical diagnosis, the test is of value only in the context of the otoneurological test battery. Distribution of results for individuals in the various groups overlap considerably. The designation of a numerical cutoff for differential diagnosis leads to error rates far in excess of what may be confidently attributed to chance.

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Vestibular Function and Motion Sickness Susceptibility: Videonystagmographic Evidence From Oculomotor and Caloric Tests

American Journal of Audiology ◽

10.1044/2020_aja-19-00050 ◽

2020 ◽

Vol 29 (2) ◽

pp. 188-198

Author(s):

Cynthia G. Fowler ◽

Margaret Dallapiazza ◽

Kathleen Talbot Hadsell

Keyword(s):

Phase Velocity ◽

Motion Sickness ◽

Repeated Measures ◽

Short Form ◽

Vestibular Function ◽

Slow Phase ◽

Test Results ◽

Normal Range ◽

Slow Phase Velocity ◽

Caloric Tests

Purpose Motion sickness (MS) is a common condition that affects millions of individuals. Although the condition is common and can be debilitating, little research has focused on the vestibular function associated with susceptibility to MS. One causal theory of MS is an asymmetry of vestibular function within or between ears. The purposes of this study, therefore, were (a) to determine if the vestibular system (oculomotor and caloric tests) in videonystagmography (VNG) is associated with susceptibility to MS and (b) to determine if these tests support the theory of an asymmetry between ears associated with MS susceptibility. Method VNG was used to measure oculomotor and caloric responses. Fifty young adults were recruited; 50 completed the oculomotor tests, and 31 completed the four caloric irrigations. MS susceptibility was evaluated with the Motion Sickness Susceptibility Questionnaire–Short Form; in this study, percent susceptibility ranged from 0% to 100% in the participants. Participants were divided into three susceptibility groups (Low, Mid, and High). Repeated-measures analyses of variance and pairwise comparisons determined significance among the groups on the VNG test results. Results Oculomotor test results revealed no significant differences among the MS susceptibility groups. Caloric stimuli elicited responses that were correlated positively with susceptibility to MS. Slow-phase velocity was slowest in the Low MS group compared to the Mid and High groups. There was no significant asymmetry between ears in any of the groups. Conclusions MS susceptibility was significantly and positively correlated with caloric slow-phase velocity. Although asymmetries between ears are purported to be associated with MS, asymmetries were not evident. Susceptibility to MS may contribute to interindividual variability of caloric responses within the normal range.

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Visually evoked slow eye movements, visual-vestibular interaction, and infratentorial lesions

Otolaryngology ◽

10.1177/019459988309100114 ◽

1983 ◽

Vol 91 (1) ◽

pp. 76-80 ◽

Cited By ~ 3

Author(s):

Carsten Wennmo ◽

Nils Gunnar Henriksson ◽

Bengt Hindfelt ◽

Ilmari PyykkÖ ◽

MÅNs Magnusson

Keyword(s):

Eye Movements ◽

Phase Velocity ◽

Brain Stem ◽

Smooth Pursuit ◽

Maximum Velocity ◽

Slow Phase ◽

Slow Phase Velocity ◽

Velocity Gain ◽

Visual Vestibular Interaction ◽

Slow Eye Movements

The maximum velocity gain of smooth pursuit and optokinetic, vestibular, and optovestibular slow phases was examined in 15 patients with pontine, 10 with medullary, 10 with cerebellar, and 5 with combined cerebello — brain stem disorders. Marked dissociations were observed between smooth pursuit and optokinetic slow phases, especially in medullary disease. A cerebellar deficit enhanced slow phase velocity gain during rotation in darkness, whereas the corresponding gain during rotation in light was normal.

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Monocular Nystagmic Responses to Caloric Stimulation

Annals of Otology Rhinology & Laryngology ◽

10.1177/000348947908800113 ◽

1979 ◽

Vol 88 (1) ◽

pp. 79-85 ◽

Cited By ~ 1

Author(s):

James W. Wolfe

Keyword(s):

Phase Velocity ◽

Rhesus Monkeys ◽

Cold Water ◽

Normal Subjects ◽

Closed Circuit ◽

Slow Phase ◽

Vestibular Nystagmus ◽

Differential Activation ◽

Slow Phase Velocity ◽

Left And Right

Twenty-five normal subjects and 173 clinical patients received standard bithermal caloric testing. Vestibular nystagmus was evaluated for cumulative slow phase velocity from the summated horizontal eye recording and independent recording of the left and right eye. These data revealed that cold water stimulation produced more intense activation of the ipsilateral eye. Simultaneous closed-circuit video and D.C. electro-oculographic recordings from eight normal rhesus monkeys in response to cold water irrigations confirmed the fact that this stimulus leads to differential activation of the extraocular muscles. A possible explanation for this finding is discussed.

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Efficacy of histaminergic drugs in experimental motion sickness

Journal of Vestibular Research ◽

10.3233/ves-2007-175-611 ◽

2008 ◽

Vol 17 (5-6) ◽

pp. 313-321

Author(s):

E.I. Matsnev ◽

E.E. Sigaleva

Keyword(s):

Phase Velocity ◽

Healthy Volunteers ◽

Motion Sickness ◽

Slow Phase ◽

High Susceptibility ◽

Double Blind ◽

Slow Phase Velocity ◽

Betahistine Dihydrochloride ◽

The Mean ◽

Oculomotor Activity

The purpose of this investigation was to evaluate the efficacy of the histaminergic drug "Betahistine dihydrochloride" in experimental motion sickness in 10 healthy volunteers (mean age 19.4 y.o.) with high susceptibility to motion sickness. Motion sickness was modeled using Coriolis (precession) accelerations (cumulative Coriolis stimulation test – CCST). Each subject took 32 mg of "Betahistine dihydrochloride" or placebo under "double – blind" conditions 1 hour before testing. The duration and slow phase velocity of the post-rotational nystagmus, the pursuit eye tracking test, and the latency, velocity and accuracy of saccades were estimated. The tolerability level of the CCST in volunteers in the betahistine series was shown to be significantly (p < 0.001) higher, as compared to placebo and baseline. The mean illusory sensations score for the experimental series was significantly lower than that in the placebo and baseline series (p < 0.01). It was found that "Betahistine" demonstrated antimotion sickness efficacy and improved oculomotor activity (increased gain during pursuit movements, faster and more accurate saccades).

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