Comparison of Speech Performance in Bimodal versus Bilateral Cochlear Implant Users.

Objective: To assess whether listening with two cochlear implants (bilateral) offers significant benefits in terms of speech perception over listening with one cochlear implant and one hearing aid (bimodal).

Methods: Retrospective review of bilateral cochlear implant recipients (24 pediatric and 26 adult). Bimodal listening was compared to bilateral listening in terms of speech perception performance at 1-year post second implant under three listening conditions: 50 dBHL, 35 dBHL, and 50 dBHL+5 SNR. Changes in speech performance from bimodal (before second implant) to bilateral (after second implant) listening were determined within subjects and compared to a separate control group of bimodal users matched for age of first implantation who never received a second implant (10 pediatric and 20 adult).

Results: In the pediatric group, compared to bimodal listening prior to a second implant, speech perception scores with bilateral implants increased significantly when measured at 50 dBHL, 35 dBHL, and 50 dBHL+5 SNR. By contrast, pediatric bimodal controls who never received a second implant failed to demonstrate similar improvement over 1 year's time. In the adult group, compared to bimodal listening prior to a second implant, speech perception scores with bilateral implants increased when measured at 50 dBHL, but were not significantly different at 35 dBHL and 50 dBHL + 5 SNR. Adult bimodal controls who never received a second implant failed to demonstrate significant improvement in all conditions over 1 year's time.

Conclusion: Bilateral listening with two cochlear implants improved speech perception performance relative to bimodal listening in the pediatric population. Improvement in the adult population was not as significant.

Level Of Evidence: 4, Retrospective Chart Review. Laryngoscope, 131:E1322-E1327, 2021.