Tapping the head activates the vestibular system

Abstract

We investigated the use of skull taps with a modified clinical reflex hammer as a method of vestibular activation. Using recently described EMG techniques to measure vestibulocollic reflexes in response to clicks, we were able to show analogous short-latency potentials to taps. The earliest responses were invariably absent on the side of a previous vestibular nerve section but were preserved in profound sensorineural or conductive hearing loss. We propose that the taps activated the vestibular apparatus directly by a bone-conducted vibration wave.

Vestibular evoked myogenic potentials: optimal stimulation and clinical application

“…Halmagyi et al [20] reported that VEMP responses are typically absent in cases of conductive hearing loss with air-bone gap measuring ‡ 20 dB, hence the response rate of VEMPs by tone-burst method is low. In contrast, the tapping method displays higher response rate of VEMPs in patients with conductive hearing loss, indicating that the VEMP provoked by tapping with a tendon hammer on the forehead is a vibratory input rather than an auditory input [21].…”

Neck Muscle Vibration Alters Visually Perceived Roll in Normals

“…Vibration can stimulate vestibular afferents such as triggering the vestibulocollic reflex. Halmagyi et al (1995) induced short-latency myogenic potentials in the SCM muscle in humans by tapping the forehead. These vestibulocollic reflex potentials are absent when the vestibular nerve is sectioned, and they likely originate in a bone-conducted vibration wave stimulating the saccule.…”

Potenciais miogênicos evocados vestibulares: metodologias de registro em homens e cobaias

“…In most studies 2,[8][9][10][11][14][15][16]18,19,24,[28][29][30][31] , the stimuli were averaged by means of ear phones instead of the bone vibrators and the intensities were, usually, above 90 dBHL.…”

“…Currently, stimuli above 90 dBHL are used 2,[8][9][10][11][14][15][16]18,19,24,[28][29][30][31] . However, in many studies, the threshold is surveyed by means of stimuli of different intensities (with ascending or descending techniques) until the lowest stimulus intensity capable of triggering a response is found 2,21,25,32 .…”