Torsional vestibulo-ocular reflex during whole-body oscillation in the upright and the supine position: II. Responses in patients after vestibular neuritis

2004 ◽  
Vol 14 (4) ◽  
pp. 353-359
Author(s):  
A. Schmid-Priscoveanu ◽  
A.A. Kori ◽  
D. Straumann

In a recent study we demonstrated that otolith input modifies the torsional angular vestibulo-ocular reflex (torVOR) of healthy human subjects: Compared to turntable oscillations in supine position, oscillations in upright position increased the gain of torVOR by 0.1 and cancelled the phase lead originating from low-frequency semicircular canal signals. We asked whether these otolith-related changes of torVOR are still present in patients after vestibular neuritis (VN). Eight patients were sinusoidally oscillated about their naso-occipital axis in supine (canal-only stimulation) and upright (canal-and-otolith stimulation) position. Three-dimensional eye movements were recorded with dual search coils. The patients showed similar otolith-related gain and phase changes of the torVOR as healthy subjects: the gain increased by about 0.1 (p < 0.05) and the low-frequency phase lead from semicircular canal signals was abolished. These results indicate that otolith function after VN is still sufficient to interact with semicircular canal signals to optimize torsional gaze stabilization when the head is upright.

1999 ◽  
Vol 9 (2) ◽  
pp. 135-144 ◽  
Author(s):  
J.H.J. Allum ◽  
T. Ledin

The centrally controlled compensation for a reduced horizontal vestibulo-ocular reflex (VOR) gain caused by a unilateral afferent deficit is usually studied following a selective surgical procedure which completely lesions the vestibular nerve or blocks the horizontal semicircular canal. The more common, unilateral, vestibular deficit encountered clinically, is a partial loss of peripheral vestibular function, following which peripheral recovery and/or central compensation may occur. We investigated changes of the VOR gain in response to a sudden, idiopathic, unilateral vestibular deficit in 64 subjects by examining the responses to low-frequency, whole-body, rotations about an earth vertical axis with different accelerations (5, 20 and 40 deg / sec 2 ) during in- and out-patient visits separated by 4 months in an attempt to identify changes brought about by peripheral recovery and by central compensation processes. Peripheral function was assumed to be measured by the response to caloric irrigation. It improved some 30% between the two visits. VOR responses for rotations towards the deficit side also improved between the two visits. Most improvement occurred for 20 deg / sec 2 accelerations. However, the correlation coefficient between rotation and caloric responses was always less than 0.6. Unlike caloric responses which improved over time, responses for rotations to the intact side did not change between the visits. For this reason, the majority of observed VOR rotation responses were nearly symmetrical at the time of the second visit, despite being below normal levels. These findings suggest that both peripheral recovery and central compensation processes help restore symmetrical VOR function for head rotations after a partial unilateral vestibular deficit. However the improvement of VOR response symmetry, particularly to slow ( < 40 deg / sec 2 ) accelerations, is largely independent of the recovery of peripheral sensitivity.


2007 ◽  
Vol 16 (6) ◽  
pp. 245-256
Author(s):  
Sandra C. Brettler ◽  
James F. Baker

Vestibulo-ocular and second-order neurons in medial and superior vestibular nuclei of alert cats were identified by antidromic and orthodromic electrical stimulation, and their responses to whole body rotations were recorded in the dark. Neurons that had spatial sensitivity most closely aligned with the anterior canal (anterior canal neurons) were compared with neurons that had spatial sensitivity most closely aligned with the posterior canal (posterior canal neurons). Responses were recorded during low frequency earth-horizontal axis pitch rotations in the normal upright posture, and during earth-vertical axis pitch with the head and body lying on the left side. During upright pitch, response phases of anterior canal neurons slightly lagged those of posterior canal neurons or primary vestibular afferents, as previously reported. During on-side pitch, anterior canal neurons showed far greater phase leads with respect to head velocity than posterior canal neurons, primary vestibular afferents, or previously reported vestibulo-ocular reflex eye movements. These results provide challenges for vestibulo-ocular reflex models to incorporate central mechanisms for phase leads among the inputs to anterior canal neurons and to explain how the anterior canal neuron signals reported here combine with other signals to produce observed vestibulo-ocular reflex behavior.


2017 ◽  
Vol 118 (5) ◽  
pp. 2819-2832 ◽  
Author(s):  
R. Panichi ◽  
M. Faralli ◽  
R. Bruni ◽  
A. Kiriakarely ◽  
C. Occhigrossi ◽  
...  

Self-motion perception was studied in patients with unilateral vestibular lesions (UVL) due to acute vestibular neuritis at 1 wk and 4, 8, and 12 mo after the acute episode. We assessed vestibularly mediated self-motion perception by measuring the error in reproducing the position of a remembered visual target at the end of four cycles of asymmetric whole-body rotation. The oscillatory stimulus consists of a slow (0.09 Hz) and a fast (0.38 Hz) half cycle. A large error was present in UVL patients when the slow half cycle was delivered toward the lesion side, but minimal toward the healthy side. This asymmetry diminished over time, but it remained abnormally large at 12 mo. In contrast, vestibulo-ocular reflex responses showed a large direction-dependent error only initially, then they normalized. Normalization also occurred for conventional reflex vestibular measures (caloric tests, subjective visual vertical, and head shaking nystagmus) and for perceptual function during symmetric rotation. Vestibular-related handicap, measured with the Dizziness Handicap Inventory (DHI) at 12 mo correlated with self-motion perception asymmetry but not with abnormalities in vestibulo-ocular function. We conclude that 1) a persistent self-motion perceptual bias is revealed by asymmetric rotation in UVLs despite vestibulo-ocular function becoming symmetric over time, 2) this dissociation is caused by differential perceptual-reflex adaptation to high- and low-frequency rotations when these are combined as with our asymmetric stimulus, 3) the findings imply differential central compensation for vestibuloperceptual and vestibulo-ocular reflex functions, and 4) self-motion perception disruption may mediate long-term vestibular-related handicap in UVL patients. NEW & NOTEWORTHY A novel vestibular stimulus, combining asymmetric slow and fast sinusoidal half cycles, revealed persistent vestibuloperceptual dysfunction in unilateral vestibular lesion (UVL) patients. The compensation of motion perception after UVL was slower than that of vestibulo-ocular reflex. Perceptual but not vestibulo-ocular reflex deficits correlated with dizziness-related handicap.


1991 ◽  
Vol 1 (3) ◽  
pp. 223-239
Author(s):  
G. Cheron

This study was intended to test the adaptive plasticity of the vestibulo-ocular reflex before and after either a midsagittal or parasagittal incision in the brainstem. Eye movements were measured with the electromagnetic search coil technique during the vestibulo-ocular reflex (VORD) in the dark, the optokinetic reflex (OKN), and the visuo-vestibular adaptive training procedure. Two types of visual-vestibular combined stimulation were applied by means of low frequency stimuli (0.05 to 0.10 Hz). In order to increase or decrease the VORD gain, the optokinetic drum was oscillated either 180∘ out-of-phase or in-phase with the vestibular stimulus turntable. This “training” procedure was applied for 4 hours. Initial measurements of the VORD were normal with a mean gain value of 0.92 ± 0.08. After 4 hours of “training” with the out-of-phase condition (180∘), VORD gain reached mean values of 1.33 ± 0.11 (n = 6 cats). In the in-phase combination, the mean VORD gain decreased from 1.0 to 0.63 ± 0.02 (n = 2 cats). No significant change of VORD phase was found in any of the cats. Midsagittal or parasagittal pontomedullary brainstem incisions were performed in 4 cats. Recovery of the VOR was tested on the 2nd, 7th, and 30th day after operation. After the 30th day, recovery of the VORD gain stabilized at about 66% of the initial preoperative value. At this stage of the recovery, the optokinetic response (OKN) of the midsagittal-Iesioned cats was practically normal: in the parasagittal-Jesioned cats, the postoperative OKN responses were asymmetric. After stabilization of recovery, lesioned cats were trained with the same adaptation procedure. Although the direct effect of the visuo-vestibular combined stimulation during the training was still operative in all lesioned cats, the adaptive plasticity was completely abolished by the lesions. These results suggest that the commissural brainstem network may play a crucial role in the acquisition of the forced VOR adaptation.


2000 ◽  
Vol 10 (2) ◽  
pp. 75-86 ◽  
Author(s):  
Jacob J. Bloomberg ◽  
Lauren A. Merkle ◽  
Susan R. Barry ◽  
William P. Huebner ◽  
Helen S. Cohen ◽  
...  

The goal of the present study was to determine if adaptive modulation of vestibulo-ocular reflex (VOR) function is associated with commensurate alterations in manual target localization. To measure the effects of adapted VOR on manual responses we developed the Vestibular-Contingent Pointing Test (VCP). In the VCP test, subjects pointed to a remembered target following passive whole body rotation in the dark. In the first experiment, subjects performed VCP before and after wearing 0.5X minifying lenses that adaptively attenuate horizontal VOR gain. Results showed that adaptive reduction in horizontal VOR gain was accompanied by a commensurate change in VCP performance. In the second experiment, bilaterally labyrinthine deficient (LD) subjects were tested to confirm that vestibular cues were central to the spatial coding of both eye and hand movements during VCP. LD subjects performed significantly worse than normal subjects. These results demonstrate that adaptive change in VOR can lead to alterations in manual target localization.


2001 ◽  
Vol 11 (1) ◽  
pp. 3-12
Author(s):  
Ji Soo Kim ◽  
James A. Sharpe

The effects of aging on the vertical vestibulo-ocular reflex (VOR), and its interactions with vision during active head motion had not been investigated. We measured smooth pursuit, combined eye-head tracking, the VOR, and its visual enhancement and cancellation during active head motion in pitch using a magnetic search coil technique in 21 younger (age < 65) and 10 elderly (age ⩾ 65) subjects. With the head immobile, subjects pursued a target moving sinusoidally with a frequency range of 0.125 to 2.0 Hz, and with peak target accelerations (PTAs) ranging from 12 to 789Âř/s 2 . Combined eye-head tracking, the VOR in darkness, and its visual enhancement during fixation of an earth-fixed target (VVOR) were measured during active sinusoidal head motion with a peak-to-peak amplitude of 20Âř at frequencies of 0.25, 0.5, 1.0 and 2.0 Hz. The efficacy of VOR cancellation was determined from VOR gains during combined eye-head tracking. VOR and VVOR gains were symmetrical in both directions and did not change with aging, except for reduced gains of the downward VOR and VVOR at low frequency (0.25 Hz). However, in the elderly, smooth pursuit, and combined eye-head tracking gains and the efficacy of cancellation of the VOR were significantly lower than in younger subjects. In both the young and elderly groups, VOR gain in darkness did not vary with the frequency of active head motion while the gains of smooth pursuit, combined eye-head tracking, and VVOR declined with increasing target frequency. VOR and VVOR performance in the elderly implicates relative preservation of neural structures subserving vertical vestibular smooth eye motion in senescence.


2019 ◽  
Vol 122 (2) ◽  
pp. 644-658 ◽  
Author(s):  
Michael C. Schubert ◽  
Americo A. Migliaccio

This is a review summarizing the development of vestibulo-ocular reflex (VOR) adaptation behavior with relevance to rehabilitation over the last 10 years and examines VOR adaptation using head-on-body rotations, specifically the influence of training target contrast, position and velocity error signal, active vs. passive head rotations, and sinusoidal vs. head impulse rotations. This review discusses optimization of the single VOR adaptation training session, consolidation between repeated training sessions, and dynamic incremental VOR adaptation. Also considered are the effects of aging and the roles of the efferent vestibular system, cerebellum, and otoliths on angular VOR adaptation. Finally, this review examines VOR adaptation findings in studies using whole body rotations.


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