Development of Eye Position Dependency of Slow Phase Velocity during Caloric Stimulation

AbstractExperiments were performed on 25 otoneurologically ‘normal’ subjects to evaluate the hot caloric test as a screening test for aminoglycoside vestibular toxicity.Using portable equipment under non-ideal conditions, it was found that there was a large inter-subject variability in nystagmic response and that, instead of a random test-retest variability, a systagmic variation in response occurred on repeated caloric stimulation with water at 44°C.A response deline (habituation) evident in both the maximum slow phase velocity and the maximum frequency occurred at second test, although the inter-test interval ranged from 24 to 72 hours.After a 3-month interval with no intervening tests, the mean value of the maximum frequency reverted back to the original level. However, there was still a significant reduction in maximum slow phase velocity at this time. Some individuals had a sustanined reduction in both parameters.Hence it is concluded that the hot caloric test, used under the conditions described in this study, is not a suitable serial screening method for aminoglycoside vestibular toxicity. The reproducibility of this test under other conditions, or any other caloric test, should be established in normal subjects befre employing, it as a serial screen for aminoglycoside vestibular toxicity.

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A review of the effects of space flight on the asymmetry of vertical optokinetic and vestibulo-ocular reflexes

Journal of Vestibular Research ◽

10.3233/ves-2003-134-610 ◽

2003 ◽

Vol 13 (4-6) ◽

pp. 255-263

Author(s):

Gilles Clément

Keyword(s):

Phase Velocity ◽

Optokinetic Nystagmus ◽

Visual Stimulation ◽

Head Movements ◽

Slow Phase ◽

Eye Position ◽

Slow Phase Velocity ◽

Ocular Reflex ◽

Vestibulo Ocular Reflex ◽

Eye Velocity

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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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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