Tinnitus suppression in patients with cochlear implants

Objective: To determine the degree of tinnitus suppression provided by curr ently available multichannel cochlear implants and to determine factors tha t can influence this process. Study Design: Prospective cohort. Setting: Tertiary-care referral center. Patients: Thirty-eight adult patients (18 years of age or older) with sever e-to-profound hearing loss and tinnitus who met criteria for cochlear impla ntation. Intervention: Cochlear implantation with a multichannel cochlear i mplant device. Main Outcome Measures: Patients rated the intensity of their tinnitus using a semiquantitative scale before and after cochlear implantation. These dat a were analyzed to determine the significance of the reduction of tinnitus after implantation. Tinnitus levels after implantation were also analyzed t o determine whether the level of speech recognition, patient gender, or the implant type influenced the degree of tinnitus reduction. Results: Statistical analysis revealed a significant reduction in 38 patien ts (92%) experiencing a reduction in tinnitus intensity. All multichannel i mplants studied afforded similar degrees of tinnitus suppression. The degre e of tinnitus reduction was not correlated with speech recognition, as meas ured by CID Everyday Sentence scores. Female patients had significantly gre ater degrees of tinnitus before implantation, but both male and female pati ents demonstrated similar levels of tinnitus after implantation. No patient experienced greater levels of tinnitus after implantation. Conclusion: All currently available multichannel cochlear implant devices p rovide effective and similar levels of tinnitus suppression when activated. Exacerbation of tinnitus as a result of cochlear implantation does not rep resent a significant risk. The mechanisms by which cochlear implants exert tinnitus suppression are, as yet, unclear.