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PubMed · 1909006

Determining side of vestibular dysfunction with rotatory chair testing.

M A Hamid
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Abstract

Determining side of vestibular lesion remains a challenging task during neurotologic investigations, particularly if auditory lateralizing signs are absent. Traditionally, absent or decreased caloric response has been regarded as evidence of unilateral vestibular deficit. But, the inability of the chair test to detect side of lesion has been generally accepted because rotation stimulates both end organs. A retrospective study postulated and tested a hypothesis that low-frequency asymmetry of sinusoidal harmonic acceleration (SHA) testing can determine side of lesion when phase is abnormal. The present prospective, double-blind study was designed to further test the retrospective study hypothesis. Results showed that SHA asymmetry detects side of unilateral vestibular deficit when phase is abnormal in 97% of cases.

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Caloric TestsHumansReaction TimeRotationVestibular DiseasesVestibular Function TestsJournal Article

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M A Hamid. 1991. Determining side of vestibular dysfunction with rotatory chair testing.. https://doi.org/10.1177/019459989110500106

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PubMed2006

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Caloric Tests↗
PubMed2006

Analysis of the vestibulo-ocular reflex time constant in patients with benign recurrent vertigo associated with head-shaking nystagmus.

CONCLUSIONS: When considering benign recurrent vertigo and a similar peripheral vestibular deficiency, the asymmetry of the vestibulo-ocular reflex (VOR) time constant (Tc) is lower in those patients with paretic head-shaking nystagmus (HSN) than in those with reversed HSN or without HSN. OBJECTIVE: To determine whether the existence of HSN is related to the time constant of the VOR in patients with benign recurrent vertigo (BRV). PATIENTS AND METHODS: This was a prospective study conducted at a tertiary care center in which patients were subjected to the head-shaking test, the caloric test and rotatory chair impulsive test on the same day. The clinical features of the disease analyzed were the disease duration, frequency of vertigo spells, time since the last vertigo spell and the existence of migraine. The results of the head-shaking test were considered positive when nystagmus appeared after head-shaking had ended. Two groups of patients were established on the basis of these results and the group that displayed HSN was divided according to the direction of nystagmus. In the impulsive test, the time constant of the VOR after ipsilesional and contralesional acceleration was analyzed, as was the symmetry of the response. The differences in the means were calculated. RESULTS: BRV was diagnosed in 25% of patients suffering recurrent spells of vertigo, of which 33 patients were HSN- and 29 were HSN+. In the latter group, vestibular migraine was frequently observed (83% of the patients), the spells of vertigo were more frequent and the patients were seen closer to the previous spell of vertigo. No differences were observed in the Tc of the VOR between HSN+ and HSN- patients, although the asymmetry of this Tc was higher in HSN- patients than in HSN+ patients. Nevertheless, the differences observed were only significant between paretic and reversed HSN patients and paretic HSN patients and HSN- patients.

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