Facial nerve stimulation after cochlear implantation: Our experience in 448 adult patients

Facial nerve stimulation (FNS) after cochlear implant activation is a well-known side effect, with an incidence rate raging between 1% and 14.9%. Some causes of deafness have been associated with a higher incidence of this entity, however, there is still no consensus regarding its pathophysiological mechanisms. Although FNS can be solved with changes in speech processor programming, in some cases this can lead to a decrease in performance. The aim of this work was to review the epidemiologic, clinical aspects, and performance results in a group of FNS after cochlear implantation. It was conducted a retrospective chart review of 448 adult patients, all implanted between 1985 and 2016. Speech perception tests results were statistically analysed, using non-parametric tests. We registered a group of 13 patients with FNS, contributing to a prevalence of 2.9%. The causes of hearing loss in this group varied between otosclerosis, Menière's disease, head trauma, and idiopathic cause. Six cases were managed by changing the programming strategy and the other seven required the deactivation of the affected electrodes. Statistical evaluation showed no statistically significant difference between the performance results of the groups with and without FNS. In this series, the overall incidence of FNS was consistent with the literature. Our study supports the current idea that FNS can frequently be eliminated by changing programming strategies or deactivating the involved electrodes, without affecting the implant's performance.