Binaural-bimodal hearing: concomitant use of a unilateral cochlear implant and a contralateral hearing aid

The benefit obtained with a contralateral hearing aid (HA) in unilateral cochlear implantees improves over time, at least during the first year after implantation.

To evaluate binaural-bimodal auditory ability and its early changes over time after unilateral cochlear implantation in patients with residual hearing in the non-implanted ear, in which they use an HA.

Sentence identification in background noise was tested in 12 patients (3 post-lingual adults and 9 pre-lingual adults and older children) under 3 listening conditions: cochlear implant (CI) alone, HA alone and CI+HA. The presentation level was 55 dB HL with a signal-to-noise ratio of +10 dB. Subjects were tested after 1-6 months of concomitant use of both devices and again after a further 7-12 months.

At the first testing session, the mean score in background noise was 34.9% with CI alone (range 0-90%) and 41.1% with both devices (range 0-100%). Seven patients could recognize sentences in noise with CI alone, and four of them showed further improvement with added amplification. At the second session, at which all subjects could recognize sentences in noise with the CI alone, seven showed further improvement with added amplification. The mean score was 60.6% with CI alone (range 10-99%) and 75.5% with both devices (range 52-100%).