Vestibular Function Pre‐ and Post‐cochlear Implantation in Adult Patients With Inner Ear Malformations: A Retrospective Cohort Study

ABSTRACT This study aimed to investigate the vestibular function (VF) across different types of inner ear malformations (IEMs) in adult patients, and to evaluate the long‐term effects of cochlear implantation (CI) on VF. A total of 129 adult patients with different types of IEMs were enrolled, and 228 ears were included in the analysis. Cervical vestibular‐evoked myogenic potential (cVEMP), ocular vestibular‐evoked myogenic potential (oVEMP), as well as video head impulse test (vHIT) were used to evaluate VF before surgery and at 12 months after surgery. Regarding vestibulo‐ocular reflex (VOR) gains, the gain of the superior semicircular canal (SSC) was significantly higher than those of the horizontal semicircular canal (HSC) and posterior semicircular canal (PSC) (both p < 0.001 ). No significant changes were observed in VOR gains or VEMP amplitudes between the preoperative assessment and the 12‐month postoperative follow‐up (29 ears, p > 0.05 ). The severity of otolith dysfunction varies according to different cochlear and vestibular malformations. Among the semicircular canals, the HSC and PSC showed greater functional impairment than the SSC. Notably, our limited data explore that CI surgery did not further exacerbate otolith or semicircular canal dysfunction at 12 months postoperatively, which needs further investigation.