The Vestibulo-Ocular Reflex during Self-Generated Head Movements by Human Subjects with Unilateral Vestibular Hypofunction

Head and eye movements of human subjects have been recorded during head-free pursuit in the horizontal plane of a target executing sinusoidal motion at a frequency of 0.26 to 0.78 Hz and a peak velocity of ±96∘/s. The target was not presented continuously but was exposed for brief durations of 120 to 320 ms as it passed through the centre of the visual field at peak velocity. This technique allowed the timing of each response to be assessed in relation to the onset of target appearance. During the first 3 to 4 target presentations, there was a progressive buildup of both head velocity and the smooth component of gaze velocity, while, simultaneously, the responses became more phase-advanced with respect to target onset. In the steady state, similar temporal response trajectories were observed for head and gaze velocity, which were initiated approximately 500 ms prior to target on-set, rose to a peak that increased with the duration of target exposure, and then decayed with a time constant of 0.5 to 1 s. Whenever the target failed to appear as expected, the gaze and head velocity trajectories continued to be made, indicating that predictive suppression of the vestibulo-ocular reflex (VOR) was taking place in darkness. In a further experiment, subjects attempted to suppress the VOR during whole body oscillation at 0.2 or 0.4 Hz on a turntable by fixating, a head-fixed target that appeared for 10 to 160 ms at the time of peak head velocity. Again, VOR suppression was initiated prior to target appearance in the same manner as for natural head movements, and when the target suddenly disappeared but rotation continued, predictive VOR suppression was observed in darkness. The similarity of these predictive effects to those obtained previously for head-fixed pursuit provides further support for the hypothesis that both pursuit and visual suppression of the VOR are controlled primarily by identical visual feedback mechanisms.

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The Linear Vestibulo-Ocular Reflex in Normal Subjects and Patients with Vestibular and Cerebellar Lesions

Journal of Vestibular Research ◽

10.3233/ves-1995-5502 ◽

1995 ◽

Vol 5 (5) ◽

pp. 349-361

Author(s):

Robert W. Baloh ◽

Qing Yue ◽

Joseph L. Demer

Keyword(s):

Eye Movements ◽

Smooth Pursuit ◽

Human Subjects ◽

Cerebellar Atrophy ◽

Linear Acceleration ◽

Normal Subjects ◽

Head Movements ◽

Normal Velocity ◽

Ocular Reflex ◽

Vestibulo Ocular Reflex

We measured the horizontal linear vestibulo-ocular reflex (LVOR) in normal human subjects and patients with abnormal angular vestibulo-ocular reflexes (AVOR) and abnormal smooth pursuit. Eye movements were induced by sinusoidal linear acceleration along the interaural axis (0.8 Hz, 0.5 g peak acceleration) on a parallel swing. Horizontal movement of each eye was recorded with an infrared limbus tracking device. Normal subjects increased LVOR sensitivity as real or imagined targets moved closer. Perceived target distance was more important than the vergence angle since changing the vergence angle alone with prisms resulted in only a slight change in LVOR sensitivity. Subjects suppressed the LVOR with real or imagined head-fixed targets. Patients with decreased horizontal AVOR responses had decreased horizontal LVOR responses with imagined earth-fixed targets in the dark. They were able to generate normal velocity LVOR responses with real earth-fixed targets. Patients with increased AVOR responses and poor smooth pursuit due to cerebellar atrophy had low LVOR responses that were minimally affected by real or imagined earth-fixed or head-fixed targets. We conclude that the smooth pursuit system and the cerebellum are critical for generating the eye movements required as subjects fixate a near target during translational head movements.

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Viewing Target Distance Influences the Vestibulo-Ocular Reflex Gain when Assessed Using the Video Head Impulse Test

Audiology and Neurotology ◽

10.1159/000493845 ◽

2018 ◽

Vol 23 (5) ◽

pp. 285-289 ◽

Cited By ~ 2

Author(s):

Patricia Castro ◽

Sara Sena Esteves ◽

Florencia Lerchundi ◽

David Buckwell ◽

Michael A. Gresty ◽

...

Keyword(s):

Head Movements ◽

Target Distance ◽

Head Impulse Test ◽

Video Head Impulse Test ◽

Gaze Stabilization ◽

Head Impulse ◽

Ocular Reflex ◽

Significant Difference ◽

Vestibulo Ocular Reflex ◽

Reflex Gain

Gaze stabilization during head movements is provided by the vestibulo-ocular reflex (VOR). Clinical assessment of this reflex is performed using the video Head Impulse Test (vHIT). To date, the influence of different fixation distances on VOR gain using the vHIT has not been explored. We assessed the effect of target proximity on the horizontal VOR using the vHIT. Firstly, we assessed the VOR gain in 18 healthy subjects with 5 viewing target distances (150, 40, 30, 20, and 10 cm). The gain increased significantly as the viewing target distance decreased. A second experiment on 10 subjects was performed in darkness whilst the subjects were imagining targets at different distances. There were significant inverse relationships between gain and distance for both the real and the imaginary targets. There was a statistically significant difference between light and dark gains for the 20- and 40-cm distances, but not for the 150-cm distance. Theoretical VOR gains for different target distances were calculated and compared with those found in light and darkness. The increase in gain observed for near targets was lower than predicted by geometrical calculations, implying a physiological ceiling effect on the VOR. The VOR gain in the dark, as assessed with the vHIT, demonstrates an enhancement associated with a reduced target distance.

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Eye-Head Movement Coordination: Vestibulo-Ocular Reflex Suppression with Head-Fixed Target Fixation1

Journal of Vestibular Research ◽

10.3233/ves-1991-1207 ◽

1991 ◽

Vol 1 (2) ◽

pp. 161-170

Author(s):

Jean-Louis Vercher ◽

Gabriel M. Gauthier

Keyword(s):

Eye Movements ◽

Time Course ◽

Mental Arithmetic ◽

Visual Space ◽

Head Movements ◽

Total Darkness ◽

Fixed Target ◽

Ocular Reflex ◽

Optokinetic Reflex ◽

Vestibulo Ocular Reflex

To maintain clear vision, the images on the retina must remain reasonably stable. Head movements are generally dealt with successfully by counter-rotation of the eyes induced by the combined actions of the vestibulo-ocular reflex (VOR) and the optokinetic reflex. A problem of importance relates to the value of the so-called intrinsic gain of the VOR (VORG) in man, and how this gain is modulated to provide appropriate eye movements. We have studied these problems in two situations: 1. fixation of a stationary object of the visual space while the head moves; 2. fixation of an object moving with the head. These two situations were compared to a basic condition in which no visual target was allowed in order to induce “pure” VOR. Eye movements were recorded in seated subjects during stationary sinusoidal and transient rotations around the vertical axis. Subjects were in total darkness (DARK condition) and involved in mental arithmetic. Alternatively, they were provided with a small foveal target, either fixed with respect to earth (earth-fixed target: EFT condition), or moving with them (chair-fixed-target: CFT condition). The stationary rotation experiment was used as baseline for the ensuing experiment and yielded control data in agreement with the literature. In all 3 visual conditions, typical responses to transient rotations were rigorously identical during the first 200 ms. They showed, sequentially, a 16-ms delay of the eye behind the head and a rapid increase in eye velocity during 75 to 80 ms, after which the average VORG was 0.9 ± 0.15. During the following 50 to 100 ms, the gain remained around 0.9 in all three conditions. Beyond 200 ms, the VORG remained around 0.9 in DARK and increased slowly towards 1 or decreased towards zero in the EFT and CFT conditions, respectively. The time-course of the later events suggests that visual tracking mechanisms came into play to reduce retinal slip through smooth pursuit, and position error through saccades. Our data also show that in total darkness VORG is set to 0.9 in man. Lower values reported in the literature essentially reflect predictive properties of the vestibulo-ocular mechanism, particularly evident when the input signal is a sinewave.

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Analysis of Vestibulo-Ocular Reflex Using Sweep Frequency Active Head Movements

Neurophysiology of the Vestibular System - Advances in Oto-Rhino-Laryngology ◽

10.1159/000416053 ◽

2015 ◽

pp. 179-183 ◽

Cited By ~ 5

Author(s):

Dennis P. O�Leary ◽

Linda L. Davis ◽

Geli-Ann Kitsigianis

Keyword(s):

Head Movements ◽

Sweep Frequency ◽

Ocular Reflex ◽

Vestibulo Ocular Reflex

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Occupation and Visual/Vestibular Interaction in Vestibular Rehabilitation

Otolaryngology ◽

10.1177/019459989511200404 ◽

1995 ◽

Vol 112 (4) ◽

pp. 526-532 ◽

Cited By ~ 1

Author(s):

Helen Cohen ◽

Maureen Kane-Wineland ◽

Laura V. Miller ◽

Catherine L. Hatfield

Keyword(s):

Motor Skills ◽

Therapy Group ◽

Exercise Program ◽

Head Movements ◽

Vestibular Disorders ◽

Essential Factor ◽

Gross Motor Skills ◽

Ocular Reflex ◽

Before And After ◽

Vestibulo Ocular Reflex

Otolaryngologists often prescribe head movement exercise programs for patients with vestibular disorders, although the effectiveness of these programs and the critical features of the exercises are poorly understood. Because many patients who dislike exercising do not follow through with their exercises, alternatives to the traditional repetitive exercises would be useful. Subjects diagnosed with vestibular disorders were treated for 6 weeks with either an outpatient exercise program that incorporated interesting, purposeful activities or a simple home program of head movements, comparable with the exercises otolaryngologists often give their patients when they do not refer to rehabilitation. Both treatments incorporated repetitive head movements in all planes in space, graduated in size and speed. Subjects were all tested before and after treatment with standard measures of vestibulo-ocular reflex and balance, level of vertigo, gross motor skills, and self-care independence. Subjects in both groups improved significantly on the functional measures, with slightly greater improvements in the occupational therapy group. The results were maintained 3 months after the cessation of intervention. These data suggest that graded purposeful activities are a useful alternative for treating this patient population and that the essential factor in any exercise program is the use of repetitive head movements.

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Inaccurate Saccades and Enhanced Vestibulo-Ocular Reflex Suppression during Combined Eye–Head Movements in Patients with Chronic Neck Pain: Possible Implications for Cervical Vertigo

Frontiers in Neurology ◽

10.3389/fneur.2017.00023 ◽

2017 ◽

Vol 8 ◽

Cited By ~ 3

Author(s):

Janine L. Johnston ◽

Pierre M. Daye ◽

Glen T. D. Thomson

Keyword(s):

Neck Pain ◽

Chronic Neck Pain ◽

Head Movements ◽

Ocular Reflex ◽

Cervical Vertigo ◽

Vestibulo Ocular Reflex

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Analysis of Human Vestibulo-Ocular Reflex During Active Head Movements

Acta Oto-Laryngologica ◽

10.3109/00016488009131714 ◽

1980 ◽

Vol 90 (1-6) ◽

pp. 184-190 ◽

Cited By ~ 57

Author(s):

R. D. Tomlinson ◽

G. E. Saunders ◽

D. W. F. Schwarz

Keyword(s):

Head Movements ◽

Ocular Reflex ◽

Vestibulo Ocular Reflex

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Plasticity in the adult vestibulo-ocular reflex arc

Philosophical Transactions of the Royal Society of London Series B Biological Sciences ◽

10.1098/rstb.1977.0045 ◽

1977 ◽

Vol 278 (961) ◽

pp. 319-334 ◽

Cited By ~ 104

Keyword(s):

Human Subjects ◽

Neural Model ◽

Reflex Response ◽

Normal Vision ◽

Ocular Reflex ◽

Field Of Vision ◽

Reflex Arc ◽

Vestibulo Ocular Reflex ◽

Plastic Changes

Human subjects with maintained reversal of their horizontal field of vision exhibit very substantial adaptive changes in their ‘horizontal’ vestibulo-ocular reflex (v.o.r.). Short durations (8 min) of vision reversal during natural head movement led to 20 % v.o.r. attenuation while long periods (4 weeks) eventually led to approximate reversal of the reflex. The reversed condition is approached by a complex, but highly systematic, series of changes in gain and phase of the reflex response relative to normal. Recovery after return to normal vision exhibits a similar duration, but different pattern, to that of the original adaptation. A chronic cat preparation with long-term optical reversal of vision has now been developed and shows similar adaptive and recovery changes at low test stimulus amplitudes, but different patterns of adaptive response at high amplitudes. An adaptive neural model employing mown vestibulo-ocular pathways is proposed to account for these experimentally observed plastic changes. The model is used to predict the adapted response to patterns of stimulation extending beyond the range of experimental investigation.

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