Clinical results for postlingually deaf patients implanted with multichannel cochlear prostheses

Abstract

Clinical results for 24 patients using the Nucleus 22-channel cochlear prosthesis have shown the device to be successful in presenting amplitude, fundamental frequency, and second formant information to patients with acquired hearing loss. For all patients, this has meant a significant improvement in their communication ability when using lipreading and some ability to understand unknown speech without lipreading or contextual cues. Approximately 40% of patients are able to understand running speech in a limited fashion without lipreading, and this ability has been evaluated using the speech-tracking technique for a number of patients. Many patients are able to have limited conversations on the telephone without using a special code. Although the prosthesis has been designed with the presentation of speech signals in mind, recognition and discrimination of environmental sounds has also been very encouraging with patients scoring 70% to 80% correct for closed set environmental sound testing. Follow-up testing has indicated that the ability to understand open set speech without lipreading continues to improve up to at least 12 months postoperatively. Open set sentence test results improved from an average of 20% at 3 months to 40% at 12 months.