An exploration of vestibular function pre and post unilateral cochlear implantation.

Objectives

To examine the effects of unilateral cochlear implantation on the balance system for adult patients with bilateral severe to profound sensory neural hearing loss.

Methods

7 CI candidates. The function of the sacculus, utricle, and three semi-circular canals (SCCs) was assessed separately using air conduction cervical vestibular evoked myogenic potentials (VEMP), vibration ocular VEMP and the video head impulse test (vHIT) respectively on each side, pre- and post-operatively.

Results

The Otoliths appear more affected by implantation than SCCs. In 3 of 7 cases VEMP was affected by implantation. In 2 cases this was associated with short-term dizziness. Discussion: Differential assessment of vestibular end organ function may elucidate how cochlear implantation affects the vestibular system. As many CI candidates have some vestibular function, pre-implant vestibular assessment may help to inform which side of implantation may best preserve that function if other audiology and surgical considerations are equal. Post-implant assessment with VEMP may help to predict short-term dizziness. More work with a larger sample will be needed to make the case for routine clinical assessment.

Conclusions

There is potential benefit of conducting multimodal vestibularassessment pre and post cochlear implantation. The otoliths appear more affected by implantation than the SCC.