Meta-analysis of speech recognition outcomes in younger and older adults with cochlear implants

Purpose: Meta-analyses were conducted to compare pre-to postoperative speech recognition improvements and postoperative scores after cochlear implantation in younger (< 60 years) and older (> 60 years) adults. Method: Studies were identified with electronic databases and through manual search of the literature. In the primary analyses, effect sizes between pre-and postoperative scores for each age group were calculated using a formula appropriate for repeated-measures designs. Using the effect sizes, two separate meta-analyses using a random-effects restricted maximum likelihood model were conducted for experiments using word and sentence recognition stimuli in quiet. Secondary meta-analyses were conducted to examine average postimplant, percent correct word recognition, sentence recognition, and speech recognition in noise in studies that included both older and younger age groups. Traditional Hedges’s g effect sizes were calculated between the two groups. Results: For the primary analyses, experiments using word and sentence recognition stimuli yielded significant, large effect sizes for the younger and older adult cochlear implant recipients with no significant differences between the older and younger age groups. However, the secondary meta-analyses of postoperative scores suggested significant differences between age groups for stimuli in quiet and noise. Conclusions: Although older and younger adults with implants achieve the same magnitude of pre-to postimplant speech recognition benefit in quiet, the overall postoperative speech recognition outcomes in quiet and noise are superior in younger over older adults. Strategies to mitigate these group differences are critical for ensuring optimal outcomes in elderly individuals who are candidates for cochlear implants.