Patient results for a multiple-channel cochlear prosthesis

Abstract

Six patients implanted with multiple-channel cochlear prostheses and using take-home, wearable speech processors, were assessed three months postoperatively using the Minimal Auditory Capabilities (MAC) battery. Results showed statistically significant improvement on virtually all tests over their preoperative performance with a hearing aid. Four patients showed significant results for open set speech testing. Lipreading tests, using word and sentence material, showed significant improvement for all patients when the cochlear prosthesis was used with lipreading compared to lipreading alone. All the above tests were carried out without training with recorded material of an unfamiliar speaker. Improvements in communication speed of 55% to 126% over lipreading alone were obtained for the six patients as assessed by the speech tracking procedure. These results are for scores averaged over eight sessions of tracking with the two conditions (with and without cochlear prosthesis). The order of conditions was alternated at each session to control practice effects. The wearable speech processor is used all day every day by five patients, and four hours a day by one patient. Reported benefit is not only for communication but also for the recognition of environmental sounds. Four patients have attempted using the telephone with some success in a restricted context situation. One patient uses the telephone routinely without using any special coding strategies. Reported problems with the cochlear prosthesis are primarily related to background noise. Results for these six patients are consistent with those obtained for two patients implanted with a prototype multiple-channel prosthesis in 1978-1979.