Purpose
The use of bilateral stimulation is becoming common for cochlear implant (CI) recipients with either (a) a CI in one ear and a hearing aid (HA) in the nonimplanted ear (CI&HA—bimodal) or (b) CIs in both ears (CI&CI—bilateral). The objective of this study was to evaluate 4 individuals who transitioned from bimodal to bilateral stimulation.
Method
Participants had completed a larger study of bimodal hearing and subsequently received a second CI. Test procedures from the bimodal study, including roaming speech recognition, localization, and a questionnaire (the Speech, Spatial, and Qualities of Hearing Scale; Gatehouse & Noble, 2004) were repeated after 6–7 months of bilateral CI experience.
Results
Speech recognition and localization were not significantly different between bimodal and unilateral CI. In contrast, performance was significantly better with CI&CI compared with unilateral CI. Speech recognition with CI&CI was significantly better than with CI&HA for 2 of 4 participants. Localization was significantly better for all participants with CI&CI compared with CI&HA. CI&CI performance was rated as significantly better on the Speech, Spatial, and Qualities of Hearing Scale compared with CI&HA.
Conclusions
There was a strong preference for CI&CI for all participants. The variability in speech recognition and localization, however, suggests that performance under these stimulus conditions is individualized. Differences in hearing and/or HA history may explain performance differences.
Speech recognition by bilateral cochlear implant users in a cocktail-party setting