Vibration-Induced Nystagmus in Patients with Unilateral Peripheral Vestibular Disorders

Abstract

This study was done to clarify the clinical significance of vibration-induced nystagmus (VIN) and to calculate the sensitivity and the specificity of the vibration test. One hundred and twelve patients with unilateral peripheral vestibular disorders and thirty normal subjects were enrolled into this study. However, patients with spontaneous nystagmus were excluded. Vibration stimuli (approximately 100 Hz) were presented to the mastoids and the forehead. Patients and normal subjects also underwent head shaking nystagmus (HSN) test and caloric testing. Among the 112 patients, 91(81 %) showed VIN which were mainly horizontal. VIN was more frequently elicited on the mastoids than on the forehead. In the majority of patients (76 cases), the direction of VIN was toward the healthy side, whereas patients with Meniere's disease (15 cases), showed nystagmus toward the affected side. None of 30 normal subjects showed VIN. Whereas HSN was found in 70 (63 %) patients and 9 (30 %) in normal subjects. Among 112 patients, 10 showed a canal paresis (CP) value of caloric testing less than 25 %, while 32 with a CP value between 25 and 40 %, 48 with a CP value between 40 and 70 %, and 22 with a CP value no less than 70 %. It is notable that with increasing CP value on caloric testing, VIN was more likely to be elicited. So VIN test is a simple, non-invasive and well-tolerated clinical test that indicates unilateral peripheral vestibular dysfunction. VIN test had greater sensitivity and specificity than HSN test in the diagnosis of unilateral peripheral vestibular disorders.

Clinical Implication and Proposed Mechanism of Direction Changing Vibration Induced Nystagmus in Unilateral Vestibular Hypofunction

“…[1][2][3] 일반적으로 일측 전정기능 저하 환자에서는 VIN의 방향이 건 측 귀를 향하는 것으로 알려졌다. 2,4,5) 진동 자극을 건 측에 인가하는 경우나 병 측에 인가하는 경우 모두 안진은 항상 건 측을 향한다고 보고와, 4) 48명의 일측 전정기능 저하 환자 에서 예외 없이 VIN이 건 측을 향한다는 보고가 있었다. 5) 메니에르병 환자에서만 안진이 병 측을 향하는 경우가 약 30%에서 발견되었다.…”

“…2,4,5) 진동 자극을 건 측에 인가하는 경우나 병 측에 인가하는 경우 모두 안진은 항상 건 측을 향한다고 보고와, 4) 48명의 일측 전정기능 저하 환자 에서 예외 없이 VIN이 건 측을 향한다는 보고가 있었다. 5) 메니에르병 환자에서만 안진이 병 측을 향하는 경우가 약 30%에서 발견되었다. 5) 그러나 정상인에서 어떤 VIN이 발견되는지와 그 기전이 무 엇인지에 대해서는 이견이 있다.…”

“…5) 메니에르병 환자에서만 안진이 병 측을 향하는 경우가 약 30%에서 발견되었다. 5) 그러나 정상인에서 어떤 VIN이 발견되는지와 그 기전이 무 엇인지에 대해서는 이견이 있다. [3][4][5][6]…”

Perception of threshold-level whole-body motion during mechanical mastoid vibration

“…Mechanical vibration applied to the mastoid is known to stimulate the vestibular system. For example, a common clinical “vibration test” for unilateral vestibular hypofunction involves the application of mechanical vibration to the mastoid [42, 46, 92], with the elicitation of nystagmus in the presence of bilateral mastoid vibration (in the range of 60 Hz to 100 Hz) indicating unilateral peripheral dysfunction. Vibration applied on the mastoid has been shown to be an excitatory stimulus to the vestibular receptors [19, 20, 90, 93], using both sinusoidal stimuli (i.e., “pure tones”) ranging from 50 Hz to 4000 Hz and short impulsive stimuli (i.e., “clicks”).…”

“…For the remainder of this paper, we use “vibration” to refer to continuous, bilateral, mechanical vibration of the mastoids using a random, noisy stimulus with a broad range of frequencies (1–500 Hz). These frequencies were chosen because they correspond to the behavioral bandwidth of vestibulo-ocular responses, which responds up to 50 Hz [44, 78] and even higher [81, 82] and because vibration at these frequencies have been shown to elicit nystagmus and body sway in humans [13, 20, 24, 45, 92]. Recent reports have shown that perceptual vestibular thresholds are correlated with vestibular migraine [57], age [5], peripheral deficits [16, 87], medication use [23] and performance in a clinical balance test [5, 47].…”