Environmental sound recognition with cochlear implants

The effects of the sinewave-band vocoder and noise-band vocoder on predicting the cochlear implant (CI) environment sound (ES) perception performance were compared through vocoder simulation experiments on 14 normal hearing (NH) listeners. Then, 9 Mandarin-speaking CI users were also tested on ES perception. The sound materials were collected from the internet. Only the sounds, which were perfectly recognized by 12 NH listeners in a pre-test procedure, were used in the formal experiments. Results showed that: (1) the carrier type has no significant effects on the average recognition rates of the 67 vocoded ESs; (2) the carrier type may have some effects on the recognition of single vocoded ES depending on the acoustic characteristics of the original sound; (3) the 9 CI users showed poorer performance than NH. More works on signal processing strategy, neural interface, and rehabilitation methods should be done to close this gap. The materials in this study can be used in future CI-ES studies.