Richard S. Tyler
Dept. of Otolaryngol., Univ. of Iowa, 200 Hawkins Dr., Iowa City, IA 52242-1078
This review discusses the speech perception results obtained from postlingually deafened adults with cochlear implants using a variety of speech coding strategies and electrode configurations. The speech feature information obtained from feature and whole-signal processing, and single and multichannel stimulation will be examined. Results will be discussed from implants developed in Innsbruck, London, Melbourne, Los Angeles, Paris, Duren, Utah, and San Francisco. Speech perception tests include simple pattern perception, audiovisual recognition, and the understanding of words without visual or contextual clues. Some patients perform poorly, whereas others are able to converse freely on the telephone. For example, word recognition from unknown lists of 50 words can range from 0% to 78% correct. Factors that contribute to successful implant use will be examined. Older patients and patients who have been deafened for long periods of time tend not to perform as well as recently deafened younger patients. The rate of learning over a five-year period shows large individual differences. Most patients show large improvements over the first 6 to 12 months, but some show continued real gains over 4 years.