Recording Vestibular Evoked Potentials Induced by Electrical Stimulation of the Horizontal Semicircular Canal in Guinea Pig

Vestibular prostheses are tools to treat vestibular disorders. Specifically, they often replace missing function by electrically stimulating the vestibular nerve (or via sensory substitution). Stimulation efficiency is typically quantified using elicited eye movements. This is an intuitive metric because compensatory eye movements are one of the key functional outputs of the vestibular system. However, this metric is difficult to measure outside of the laboratory environment, thus unavailable as a learning signal for a closed-loop prosthetic. Here we electrically stimulated and recorded vestibular evoked potentials (VEP) in the same semicircular canal of a guinea pig. The average recorded signals (including stimulation artifact and VEP) were analyzed to identify relevant temporal features and changes in response amplitude when the vestibular system was activated. Then we used Rectified Bin Integration (RBI) to measure vestibular response after all artifacts subsided. The RBI values also changed non-linearly around the activation threshold of the vestibular nerve. These preliminary results suggest there is relevant information in the evoked response and that both time domain and RBI merit further investigation as a useful metric of stimulation efficacy.