Elicitation of Vestibular Side Effects by Regional Vibration of the Head,

Abstract : Vestibular side effects including visual and postural illusions, nystagmus, and motion sickness were elicited using a vibrator applied to different regions of the head. Although a commercially available vibrator (60 Hz, 120 pulses/sec) can elicit side effects, its use was enhanced by varying the vibration frequency and optimizing the stimulus conditions for perception of illusions and elicitation of motion sickness. Both horizontal and vertical nystagmus were elicited, the latter inconsistently. A strong apparent movement (and displacement) of a dimly lighted target that resembled the oculogyral illusion and apparent self-motion were consistently elicited. Motion sickness was readily elicited in some subjects but in other subjects even stimulation during rotation failed. The findings indicate that the use of vibratory stimulation should be exploited to determine whether, in addition to its use in the laboratory as a research device, it has a place in the clinic as a means of evaluating canalicular function. (Modified author abstract)