Predictors of cochlear implant performance

Open set speech understanding with cochlear implants, without speechreading , is nowadays a common finding. However, there is a large variation in spee ch understanding between cochlear implant users. We tried to find pre-opera tive parameters which predicted the postoperative results. Thirty-seven adu lt post-lingually deafened Nucleus cochlear implant users with a mean age o f 46 years (range 16-68) and a mean duration of deafness of 15 years (range 1.5-47) were studied. Pre-operatively, we performed pure-tone audiometry, round window and ear canal electrical stimulation, psychological tests and imaging. Additionally, we measured pre-operatively speech understanding in the auditory, the visual and the audiovisual conditions with several tests which were also administered after 6 and 12 months' implant experience. Cor relation analysis between the pre-operative variables and the post-operativ e factors showed that duration of deafness and residual hearing are the mos t important predictors. The temporal difference limen in pre-operative roun d window electrical stimulation is a secondary predictor.