The role of testing vestibular function before cochlear implantation

Introduction: Whether the surgical technique (especially round window vs. cochleostomy) may influence the vestibular outcome of cochlear implanytation (CI) is still a matter of debate. Objectives: Our aim was to define if postoperative vestibular symptoms were more related to the surgical procedure or to the preoperative vestibular function, in unilateral and bilateral CI candidates. Methods: This study is a retrospective analysis of our adult CI series operated by the same surgeon (DZ) over the last 3 years, excluding patients with Ménière’s disease and positive history of vestibular disorders. (N=78) The outcomes of the pre-operative vestibular assessment were extracted from the database of the Vestibular Disorders Unit of the tertiary referral University Hospital of Milano. Results: We classified the patients according to the normal or deficient post-op. vestibular response of the operated ear measured by videoculography, caloric testing and video-impulse test. Sensorial analysis by static posturography was also included. The incidence of postoperative vertigo was related to the pre.operative vestibular function and not to the surgical procedure. The results are discussed with the revew of the literature. Conclusion: Our results confirm the importance of preoperative vestibular testing, in order to better counsel the patient on the foreseeable post-operative course, to identify those patients who will need a vestibular rehabilitation and, possibly, to help select the ear (side) to be operated when the hearing loss is symmetrical.