Prognostic indicators of speech recognition performance in adult cochlear implant users: a prospective analysis.

In a previously reported retrospective study of 32 prelingually and postlingually deaf adult Nucleus 22-channel cochlear implant users, multiple parameters were analyzed to determine which were predictive of postimplant speech recognition. Duration of deafness divided by age at implantation, and the psychophysical measures of 1) the threshold slope function (50 to 400 Hz) and 2) detection threshold at 400 Hz obtained preimplantation by means of a round window ball electrode were found to correlate most highly with postimplant performance. A more recent prospective study of 22 consecutive perilingually and postlingually deaf adult Nucleus users has reaffirmed the previous findings. Results revealed a highly significant correlation (r = .873, p < .0001, df = 20) between estimated and realized speech perception. In view of these findings, it would appear that there are variables that can be used preoperatively to predict perilingually and postlingually deaf adults' speech performance. The implications of these findings with respect to patient counseling and realistic expectations both for the patient and the implant team are obvious.