Laterality of vestibular evoked myogenic potentials.
To clarify the laterality of acoustically evoked vestibulocollic reflexes with a short latency (vestibular evoked myogenic potentials, VEMPs). responses on the bilateral sternocleidomastoid muscles (SCMs) to unilateral acoustic stimulation were studied. Twenty-one healthy volunteers were enrolled. Surface electrodes were placed on the upper half of each SCM (active) and on the lateral end of the upper sternum (reference). Clicks and 500-Hz tone-bursts (95dB nHL) were used. All subjects showed positive-negative biphasic responses on the ipsilateral SCM by clicks and tone-bursts. Click-stimulation of 41 of the 42 ears did not evoke any response on the contralateral SCM. However, in one ear, positive-negative biphasic responses were evoked on the contralateral SCM. Recordings on the contralateral SCM by tone-bursts showed no response in 32 ears, small positive-negative biphasic responses in four ears, and small negative-positive biphasic responses in six ears. These findings show that VEMPs are ipsilateral-dominant, basically consistent with the hypothesis that they are of saccular origin.
Murofushi
Toshihisa
T
Department of Otolaryngology, Faculty of Medicine, University of Tokyo, Tokyo, Japan. toshi-tky@umin.ac.jp
Ochiai
Atsushi
A
Ozeki
Hidenori
H
Iwasaki
Shinichi
S
D000161:Acoustic Stimulation; D000328:Adult; D000368:Aged; D001300:Audiometry, Evoked Response / Q000379:methods; D004576:Electromyography; D005072:Evoked Potentials, Auditory / Q000502:physiology*; D005260:Female; D007839:Functional Laterality / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009334:Neck Muscles / Q000502:physiology*; D014725:Vestibular Nerve / Q000502:physiology*