Vestibular Implantation Can Work even after More Than 20 Years of Bilateral Vestibular Hypofunction

Objective To determine whether prosthetic stimulation delivered via a vestibular implant can elicit artificial sensation of head movement despite long (23-yr) duration adult-onset ototoxic bilateral vestibular hypofunction (BVH). Study Design Case report. Setting Tertiary care center as part of a first-in-human clinical trial. Patients One. Interventions Unilateral vestibular implantation with an investigational multichannel vestibular implant in a 55-year-old man with a well-documented 23-year history of aminoglycoside-induced BVH. Main Outcome Measures Electrically evoked vestibulo-ocular reflexes (eeVOR). Results Vestibular implant stimulation can drive stimulus-aligned eeVOR and elicit a vestibular percept 23 years after the onset of bilateral vestibulopathy. Prosthetic stimulation targeting individual semicircular canals elicited eye movements that approximately aligned with each targeted canal's axis. The magnitude of the eeVOR response increased with increasing stimulus current amplitude. Response alignment and magnitude were similar to those observed for implant recipients who underwent vestibular implantation less than 10 years after BVH onset. Responses were approximately stable for 18 months of continuous device use (24 h/d except during sleep). Conclusions Vestibular implantation and prosthetic electrical stimulation of semicircular canal afferent nerves can drive canal-specific eye movement responses more than 20 years after the onset of ototoxic vestibular hypofunction.