The dynamics of the vestibulo-ocular reflex in patients with vestibular neuritis

Brantberg, Krister; Magnusson, Måns

doi:10.1016/0196-0709(90)90066-5

Cited by 22 publications

(9 citation statements)

References 24 publications

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“…These factors are mainly known to decrease both the VOR gain and time constant and not to cause any asymmetry. After unilateral vestibular function loss, VOR gain is asymmetrically reduced, while the time constant is reduced symmetrically (17). The reduction of the time constant has been proposed to be due to habituation in the vestibular nuclei to the asymmetric activity.…”

Section: Discussionmentioning

confidence: 99%

Passive Sustained Turning of the Head Induces Asymmetric Gain of the Vestibulo-Ocular Reflex in Healthy Subjects

Padoan¹

1998

Acta Oto-Laryngologica

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In order to test the hypothesis of an interaction between neck proprioception and the vestibulo-ocular reflex (VOR), we rotated 16 healthy subjects both facing forward and with their heads passively turned 70 degrees to either side. We found that gain tended to be lower when the subjects were rotated with their heads turned opposite to the direction of rotation compared to when they were rotated in the same direction, but facing forward. Although our findings were not statistically significant, they suggest that there is a measurable interaction between neck proprioception and the VOR in subjects with normal vestibular function. Asymmetric neck muscle proprioceptive signals seem to give rise to asymmetric functioning of the VOR, which, at least in part, could be the pathogenesis of cervical dizziness. If so, this could lead to misinterpretation of vestibular assessments in patients with neck pain who also complain of dizziness.

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Section: Discussionmentioning

confidence: 99%

Passive Sustained Turning of the Head Induces Asymmetric Gain of the Vestibulo-Ocular Reflex in Healthy Subjects

Padoan¹

1998

Acta Oto-Laryngologica

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“…Partial to complete resolution of aVOR gain deficits within weeks of onset of vestibular neuritis (VN) to low-velocity assessments is well established (Brandtberg and Magnusson 1990; Nadol 1995). Persistent deficits (years) have been documented when subjects are assessed with high-velocity head movement testing and oculomotor recording methods (Aw et al 2001).…”

Section: Introductionmentioning

confidence: 99%

Characterizing high-velocity angular vestibulo-ocular reflex function in service members post-blast exposure

2010

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Blasts (explosions) are the most common mechanism of injury in modern warfare. Traumatic brain injury (TBI) and dizziness are common sequelae associated with blasts, and many service members (SMs) report symptoms worsen with activity. The purpose of this study was to measure angular vestibulo-ocular reflex gain (aVOR) of blast-exposed SMs with TBI during head impulse testing. We also assessed their symptoms during exertion. Twenty-four SMs recovering from TBI were prospectively assigned to one of two groups based on the presence or absence of dizziness. Wireless monocular scleral search coil and rate sensor were used to characterize active and passive yaw and pitch head and eye rotations. Visual analog scale (VAS) was used to monitor symptoms during fast walking/running. For active yaw head impulses, aVOR gains were significantly lower in the symptomatic group (0.79 ± 0.15) versus asymptomatic (0.87 ± 0.18), but not for passive head rotation. For pitch head rotation, the symptomatic group had both active (0.915 ± 0.24) and passive (0.878 ± 0.22) aVOR gains lower than the asymptomatic group (active 1.03 ± 0.27, passive 0.97 ± 0.23). Some SMs had elevated aVOR gain. VAS scores for all symptoms were highest during exertion. Our data suggest symptomatic SMs with TBI as a result of blast have varied aVOR gain during high-velocity head impulses and provide compelling evidence of pathology affecting the vestibular system. Potential loci of injury in this population include the following: disruption of pathways relaying vestibular efference signals, differential destruction of type I vestibular hair cells, or selective damage to irregular afferent pathways-any of which may explain the common discrepancy between reports of vestibular-like symptoms and laboratory testing results. significantly reduced pitch aVOR in symptomatic SMs and peak symptom severity during exertional testing support earlier findings in the chronic blast-exposed active duty SMs.

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“…Recovery from dynamic vestibular imbalance after VN is frequency-dependent (Paige 1989). When tested with low accelerations used in clinical turntable testing or caloric irrigation, the gains of the vestibuloocular reflex (VOR) become symmetrical within several weeks (Brantberg and Magnusson 1990;Imate and Sekitani 1993;Allum and Ledin 1999). When tested with high accelerations generated by Halmagyi-Curthoys head impulses (Halmagyi and Curthoys 1988), however, the horizontal VOR often remains asymmetrical, even after many years (Schmid-Priscoveanu et al 1999, 2001Aw et al 2001).…”

Section: Introductionmentioning

confidence: 99%

Recovery of the High-Acceleration Vestibulo-ocular Reflex After Vestibular Neuritis

Palla

Straumann

2004

JARO

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Vestibular neuritis (VN) usually leads to a sudden gain asymmetry of the high-acceleration horizontal vestibulo-ocular reflex (VOR). We asked whether this asymmetry decreases over time indicating peripheral recovery and/or central compensation. The horizontal VOR during rapid rotational head impulses to both sides was recorded with search coils in 37 patients at different time periods (1-240 weeks) after the onset of VN. In ten patients, sequential measurements were performed. Gains of the VOR during head impulses toward the ipsilesional side significantly increased after the initial drop (average gains: < 1 week: 0.35; 1-4 weeks: 0.33; 4-40 weeks: 0.55; 40-240 weeks: 0.50). Gains on the contralesional side, however, were only slightly reduced and showed no significant change. We conclude that, in contrast to patients after hemilabyrinthectomy or unilateral vestibular neurectomy, the ocular response to ipsilesional rotations in patients after VN improves over time. This finding suggests that ipsilesional recovery is peripheral or, if central, depends on spared peripheral function. The physiology of linear and nonlinear VOR pathways predicts a considerable gain reduction for contralesional head impulses if central compensation mechanisms are not engaged. Thus, the relatively preserved gain on the contralesional side can be explained only by central ''upregulation''. Apparently, for high accelerations of the head, effective central compensation after VN does not aim to balance the gains of the VOR but tries to boost the contralesional gain close to normal.

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The dynamics of the vestibulo-ocular reflex in patients with vestibular neuritis

Cited by 22 publications

References 24 publications

Passive Sustained Turning of the Head Induces Asymmetric Gain of the Vestibulo-Ocular Reflex in Healthy Subjects

Passive Sustained Turning of the Head Induces Asymmetric Gain of the Vestibulo-Ocular Reflex in Healthy Subjects

Characterizing high-velocity angular vestibulo-ocular reflex function in service members post-blast exposure

Recovery of the High-Acceleration Vestibulo-ocular Reflex After Vestibular Neuritis

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