Successful cochlear implantation in a patient with preexisting bilateral deep brain stimulation: A case report with two-year follow-up

Introduction: Cochlear implantation (CI) in patients with preexisting bilateral deep brain stimulation (DBS) systems is rarely performed because of concerns regarding electromagnetic interference, device malfunction, telemetry disruption, and intraoperative safety. We report the successful cochlear implantation of a patient with bilateral ventral intermediate nucleus (VIM) DBS, with two years of clinical and audiologic follow-up demonstrating sustained outcomes without DBS-related complications. Case Report: A 79-year-old man with progressive bilateral sensorineural hearing loss and medically refractory essential tremor treated with staged bilateral VIM DBS underwent right cochlear implantation after obtaining limited benefit from hearing aids. Preoperatively, right hearing-aid testing demonstrated consonant-nucleus-consonant (CNC) word recognition of 16% and an AzBio score of 33%. Right cochlear implantation was performed using a Cochlear Americas CI632 electrode array. Full electrode insertion was achieved, with normal intraoperative neural response telemetry and no surgical complications. Postoperatively, speech perception improved substantially, with CNC word recognition increasing to 74% at five months and 70% at nine months. Bimodal AzBio sentence scores were 84% at five months and 72% at nine months. During two years of follow-up, there were no episodes of DBS malfunction, telemetry interference, programming difficulty, or cochlear implant device failure. Conclusion: Cochlear implantation can be safely performed in patients with preexisting bilateral DBS systems with careful perioperative planning and device management. This case adds to the limited literature by demonstrating successful cochlear implantation in a patient with established bilateral VIM DBS, including successful intraoperative device testing, substantial postoperative improvement in speech perception, and sustained compatibility between the cochlear implant and DBS systems over two years of follow-up.