The amplitude of Vestibular Evoked Myogenic Potentials (VEMP) depends linearly on preinnervation

Objective: Vestibular evoked myogenic potentials (VEMP) are evoked by loud clicks or tones, which induce an inhibition of the electromyographic activity (EMG) of the sternocleidomastoid (SCM) muscle ipsilateral to the sound source. A reduction of VEMP amplitude is a sign of vestibular dysfunction. The VEMP amplitude depends on both the loudness of the stimulus and the level of preinnervation. Thus, it has been suggested to monitor the rectified EMG during the examination in order to correct for the influence of preinnervation. We intended to quantify the influence of preinnervation on VEMP amplitude. Methods: Ro…