Vestibulo-ocular reflexes in peripheral labyrinthine lesions

Honrubia, Vicente; Jenkins, Herman A.; Baloh, Robert W.; Yee, Robert D.; Lau, Clifford G. Y.

doi:10.1016/s0196-0709(84)80016-2

Cited by 44 publications

(16 citation statements)

References 17 publications

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“…The constant values used are based on studies using physiological stimulation of the horizontal canal of normal subjects and patients with unilateral labyrinthine paralysis [Honrubia et al, 1982[Honrubia et al, , 1984[Honrubia et al, , 1985Sills and Honrubia, 1978; Working Group on Evaluation of Tests for Vestibular Function, 1992;Galiana and Outerbridge, 1984], as the most likely representative data since BPPV stimulation is applied to only a single semicircular canal. In order to deduce the equivalent stimulus that will induce similar responses as those illustrated in figure 1, the transfer function equation 1 is inverted, and the stimulus is expressed in terms of head acceleration:…”

Section: Methodsmentioning

confidence: 99%

Theoretical Models for the Mechanisms of Benign Paroxysmal Positional Vertigo

House¹,

Honrubia²

2003

Audiol Neurotol

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Benign paroxysmal positional vertigo (BPPV) is a common vestibular disorder resulting from a malfunction of the semicircular canal. Prior studies attempting to elucidate the mechanics of BPPV have focused on clinical and laboratory findings, and have discussed theoretical aspects only in qualitative terms. The goal of this study is to create a mathematical description of BPPV mechanics based on biophysical principles, in order to improve the physiopathological understanding of the most common varieties of the disorder, canalithiasis and cupulolithiasis. First, the abnormal stimulus being applied to the vestibular system during BPPV episodes is estimated by an analysis of the vestibulo-ocular reflex (VOR) response of clinical BPPV patients. The magnitude and time course of the head motion stimulus that would, in a normal test subject, produce a VOR response similar to that observed during BPPV nystagmus are inferred from eye motion data using an inverse transfer function approach. Next, physicomathematical models to describe the mechanics of the abnormal stimulations of the crista are created: the cupulolithiasis model is based on the principle that dense particulate matter becomes attached to the cupula of affected patients and effectively changes the specific gravity of the cupula; the canalithiasis model is based on the hydrodynamic effects from a cluster of particles falling within the canal endolymph. The stimuli predicted by these two models are compared to the stimuli estimated from physiological and clinical studies. The model predictions are found to be consistent with the empirical evidence for a reasonable set of model parameters. The cupulolithiasis model predicts a value of 0.69 µg as the mass of particles contributing to the disorder. The canalithiasis model predicts a value of 0.087 µg. These results support and expand our understanding of the mechanisms underlying the production of the cupulolithiasis and canalithiasis varieties of vertigo in humans. On the basis of these models, several predictions that can help the clinician improve the evaluation of BPPV patients are discussed.

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Section: Methodsmentioning

confidence: 99%

Theoretical Models for the Mechanisms of Benign Paroxysmal Positional Vertigo

House¹,

Honrubia²

2003

Audiol Neurotol

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“…Symmetry measurements in the patients with bilateral lesions did not differ significantly from those in normal subjects at any frequency. As we have reported in detail [3, 10,113 on the symmetry of rotational responses in patients with unilateral peripheral vestibular lesions, this report concentrates only on overall gain and phase measurements. For sinusoidal frequencies of 0.4 Hz and below a fast Fourier transform was executed, giving the magnitude and phase of the fundamental and first two harmonics.…”

Section: Methodsmentioning

confidence: 99%

Changes in the human vestibulo‐ocular reflex after loss of peripheral sensitivity

Baloh

Honrubia

Yee

et al. 1984

Annals of Neurology

149

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Quantitative rotational testing was used to study changes in the vestibulo-ocular reflex of patients with unilateral and bilateral peripheral vestibular lesions. Compared with normal subjects, the patients exhibited a characteristic pattern of decreased gain and increased phase lead at low frequencies of sinusoidal stimulation and decreased time constants on impulsive stimulation. By contrast, gain and phase measurements on high-frequency-low-amplitude sinusoidal stimulation were often normal. In the patients with bilateral lesions, the results of caloric testing correlated with the results of low-frequency rotational testing but not with the results of high-frequency testing. There are two main clinical implications of these findings. First, patients with absent response to caloric stimulation (unilateral or bilateral) may have a normal response to high-frequency sinusoidal rotation (i.e., the frequencies that constitute most natural head movements). This probably explains why such patients do not report oscillopsia. Second, low-frequency sinusoidal rotational testing and caloric testing are more sensitive than high-frequency sinusoidal or impulsive rotational testing for detecting early loss of vestibular sensitivity due, for example, to ototoxic drugs.

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“…Further, enough overlap exists between normal and pathologic response parameters to limit test utility in individual cases. While R-L response asymmetry might be expected to best localize the side of lesion, even this measure has restricted utility in most patients (3,6,7), presumably because of adaptive changes which restore balanced VOR responses.…”

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confidence: 99%

Nonlinearity and Asymmetry in the Human Vestibulo-ocular Reflex

Paige

1989

Acta Oto-Laryngologica

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The horizontal vestibulo-ocular reflex was studied in normal and unilaterally vestibulopathic human subjects; the latter before and after surgical vestibular ablation. Subjects were oscillated at 0.025-4 Hz, 50 o/s peak head velocity, and for 0.025 and 0.25 Hz, at 50-300 o/s peak head velocity. Gain (peak eye/head velocities), phase (delay in degrees between peak eye and head velocities), and asymmetry (including d.c. bias; the average eye velocity over the cycle) were assessed for each rotation. In patients preoperatively, gain was subnormal while phase lead was greater than normal only at lowest frequencies. As head velocity increased at 0.025 and 0.25 Hz, gain dropped in patients, but not in normals. Furthermore, d.c. bias at 0.25 Hz tended to shift abnormally toward the lesioned side in most patients. After surgery, gain dropped and phase lead rose for all stimuli, but showed varied recovery over 4 months. d.c. bias also rose after surgery, and showed an enhancement with increasing head velocity at 0.25 Hz. d.c. bias remained unchanged even after 4 months for 300 o/s rotations, but disappeared at low head velocity. d.c. bias (and other asymmetry measures) represents a lateralizing sign which can be improved by utilizing high head velocities at moderate frequencies.

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Vestibulo-ocular reflexes in peripheral labyrinthine lesions

Cited by 44 publications

References 17 publications

Theoretical Models for the Mechanisms of Benign Paroxysmal Positional Vertigo

Theoretical Models for the Mechanisms of Benign Paroxysmal Positional Vertigo

Changes in the human vestibulo‐ocular reflex after loss of peripheral sensitivity

Nonlinearity and Asymmetry in the Human Vestibulo-ocular Reflex

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