From vestibular implant to cortex: electrically evoked vestibular responses

Area of Science:

• Neuroscience
• Otolaryngology
• Biomedical Engineering

Background:

• Understanding central vestibular pathways is crucial but challenging.
• Vestibular implants provide direct electrical stimulation of the vestibular end organ.
• Innovative measurement techniques are needed to study vestibular function.

Purpose of the Study:

• To explore the feasibility of using vestibular implant stimulation to elicit vestibular evoked potentials (VEPs).
• To utilize electroencephalography (EEG) for recording VEPs.
• To investigate short and long latency responses to vestibular implant stimulation.

Main Methods:

• Nine participants received vestibular implant stimulation targeting ampullary nerves.
• Short latency potentials were recorded using single-channel EEG.
• Long latency potentials were recorded using 128-channel EEG in three participants.
• Responses were analyzed for latency, shape, location, and correlation with stimulus intensity.
• EEG thresholds were compared with patient perception and vestibulo-ocular reflex thresholds.

Main Results:

• The measurement setup was feasible for obtaining VEPs.
• A consistent short latency vestibular brainstem response was identified in five participants.
• Long latency responses showed localized components with amplitudes correlating to stimulus intensity.
• Electrically evoked response thresholds aligned with patient perception and eye movement recording thresholds.

Conclusions:

• Vestibular implant stimulation reliably elicited reproducible short and long latency responses.
• This technique opens new avenues for researching vestibular processing.
• It provides a method for evaluating vestibular implant efficacy.