Predictive factors of vertigo following cochlear implantation in adults

Objectives The occurrence of vertigo after cochlear implantation surgery is one of the most common complications, and often transient. The purpose of this study was to evaluate the occurrence of vertigo after unilateral or bilateral cochlear implantation as well as to identify potential predictive factors. Materials and methods Patients who have undergone cochlear implantation and vestibular assessment pre- and postoperatively were included retrospectively. The presence of vertigo before and after surgery was noted. Postoperative vertigo duration was divided into 3 categories: immediate postoperative (less than 2 months), transient postoperative (between 2 months and 1 year), and persistent postoperative (greater than 1 year). Pre- and postoperative vestibular assessment results (caloric irrigation and VEMP tests) as well as patients' age, operated side, surgical technique for round window access, and characteristics of the electrode array were all analyzed as potential predictive factors of postoperative vertigo. Results A total of 166 cochlear implants (137 patients) were included in the study, with a mean age of 57.5 +/- 16.4 years. Of these, 36% developed postoperative vertigo, of which 19.3% was immediately postoperative. At 1 year postoperatively, 6 cases (3.6%) had persistent disabling vertigo, with 2 cases (1.2%) having no history of vertigo prior to cochlear implantation. Regarding caloric irrigation, 21% of the patients had a vestibular deficiency before surgery, and the same percentage had decreased vestibular responses. At 2 months after cochlear implantation, 31% of the patients exhibited an alteration in their vestibular test results, and 23.5% had experienced immediate postoperative vertigo. None of the factors studied (age, operated side, surgical technique, electrode array characteristics, and vestibular test alteration) correlated with the occurrence of short-term or long-term postoperative vertigo. Conclusion The occurrence of vertigo after cochlear implantation is difficult to predict by the healthcare team and may develop into an invalidating condition. Each vestibular examination performed routinely only evaluates a specific vestibular organ dysfunction. Therefore, combining several vestibular assessments tests before and after cochlear implantation can increase their sensitivity of predicting the occurrence and eventual persistence of this symptom.