Hearing progress and fluctuations in bimodal-binaural hearing users (unilateral cochlear implants and contralateral...

Mean scores achieved using a cochlear implant (CI) plus a hearing aid (HA) were consistently higher (statistically non-significant) than those for CI alone. The addition of a contralateral HA partially compensated for the negative hearing fluctuations as well as for the slow initial progress with the CI.

To examine hearing progress over the first 3 years after unilateral cochlear implantation in users who had residual hearing in the non-implanted ear at the time of surgery and continued to use a HA in that ear thereafter.

Thirteen patients were followed up for 36 months after continuous concomitant use of a CI and a contralateral HA. To evaluate hearing progress, sentence identification in background noise (presentation level, 55 dB; S/N ratio, +10 dB) was tested for CI alone and for CI with contralateral HA (CI+HA). Subjects were tested after 6, 12, 18, 24, and 36 months of concomitant use of both devices. Mixed regression model was used to evaluate the group's progression of scores and the added value of a contralateral HA over time.

When last tested (36 months after CI) the mean group score for CI alone was 72.6% +/- 19.3%, and 12/13 patients scored at least 65% with either CI alone or CI+HA. Mean scores achieved using CI+HA were consistently higher than those for CI alone. Percentage improvement in CI+HA relative to CI alone was highest (19.2%) after 18 months of concomitant usage and then diminished gradually to 7.7% at 36 months. Most patients showed some negative fluctuations in performance with CI alone at some point during the 36 months of post-CI follow-up.