Nucleus 22-channel cochlear implant: preliminary observations.

A carefully designed study was undertaken in 1982 to evaluate the performance of individuals who received the Nucleus 22-channel cochlear implant. All patients were profound-totally deaf, adults with a postlingual onset of impairment. The preoperative evaluation, prosthesis fitting, training, and postoperative testing were consistent across clinics. Single-subject studies, where each patient acted as his/her own control, revealed that of the 37 subjects, 16-24 obtained significant improvement (P less than or equal to 0.001) on unpracticed, unfamiliar recorded speech tests from the Minimal Auditory Capabilities (MAC) Battery, when using hearing alone (no lipreading). In addition, virtually all patients showed improvement in recognition of speech material with lipreading. The data support the efficacy of a feature extraction coding system where specific formant and amplitude information are transmitted via direct electrical stimulation to the cochlea.