Younger- and Older-Age Adults With Unilateral and Bilateral Cochlear Implants: Speech and Spatial Hearing Self-Ratings and Performance

Objective: Compare results of cochlear implantation in younger and older adults in the domains of disability and handicap, as well as in tests of word recognition and localization, across unilateral implant (CI), bilateral (CI + CI), and CI with an acoustic hearing aid in the nonimplanted ear (CI + HA). Design: Three parts: retrospective (postimplant only) analysis; prospective (preimplant versus postimplant); correlation between age and benefit from CI versus CI + CI. Two age groups, older and younger than 60 years, for the first 2 analyses; age is a continuous variable for the third analysis. Setting: Tertiary referral hospital clinic. Patients: Postlingually severely-to-profoundly hearing-impaired adults: Totals of 68 CI, 36 CI + CI, and 38 CI + HA in the retrospective part of the study; totals of 30 CI, 18 CI + CI, and 16 CI + HA in the prospective parts. Numbers vary from these totals on individual measures. Interventions: Patients receive either 1 or 2 cochlear implants; some with 1 CI opt to retain a hearing aid in the nonimplanted ear. Outcome Measures: Principal measures: Hearing Handicap Inventory for the Elderly, Hearing Handicap Questionnaire, Speech, Spatial and Qualities of Hearing Scale, word recognition test, and soundfield localization test. The study is exploratory, but proceeding from a null hypothesis of no expected contrast as a function of patient age. Results: All patient groups show significant benefit after implantation. No significant age-related differences are observed in patients with unilateral implant, nor in CI + HA group. In the CI + CI group, the younger cohort showed very substantial increases in both performance and self-rated abilities; the older cohort provides more mixed outcomes. Conclusion: Results for the CI group confirm and extend earlier research. The result for the younger group of CI + CI patients demonstrates the consistent incremental benefit obtained from a bilateral procedure. The mixed outcome observed in the older CI + CI group might be due to individual differences in interaction between effects of aging and the ability to integrate binaural cues.