Vestibular evoked myogenic potential (VEMP) with galvanic stimulation in normal subjects.

Introduction: The vestibular evoked myogenic potential (VEMP) generated by galvanic vestibular stimulation (GVS) is related to the vestibulo-spinal pathway. The response recorded from soleus muscle is biphasic with onset of short latency (SL) component around 60 ms and medium latency (ML) component around 100 ms. The first component reflects otolith function (sacule and utricle) and the last deals with semicircular canals.

Aim: To describe VEMP generated by GVS.

Methods: In this cross-sectional clinical study, VEMP was generated by 2 mA/400 ms binaural GVS, frequency of 5-6 ms that was recorded from soleus muscles of 13 healthy adults, mean age 56 years. The subjects remained standing, head turned contralateral to the GVS applied to the mastoid. Thirty GVS were applied to the mastoid in the position cathode right anode left, followed by 30 in inverted position. SL and ML were measured.

Results: SL and ML components were recorded from both legs of all participants and were similar. The average of SL component was 54 ms and of ML was 112 ms.

Conclusion: The components SL and ML of the VEMP response in soleus were reproducible and are useful measures of vestibular-spinal function.