MECHANISMS OF VOWEL RECOGNITION FOR INERAID PATIENTS FIT WITH CONTINUOUS INTERLEAVED SAMPLING PROCESSORS

Vowel recognition was assessed for eight, cochlear implant patients wh o use the Ineraid's six-electrode array. Recognition was tested in thr ee conditions: with the Ineraid after years of experience; with a CIS processor at fitting of the processor; and with the CIS processor afte r 1 month's experience. At the time of fitting of the CIS processor, v owel recognition was not superior to that with the Ineraid. Recognitio n improved significantly over the period of a month. At 1 month, perfo rmance was significantly better with the CIS processor than with the I neraid. This outcome is interpreted to mean that remapping of the vowe l space is necessary following fitting with the CIS processor and some of the remapping occurs over a time period of days or weeks, rather t han hours. Vowel errors at one month could be accounted for by two mec hanisms. One is that patients attended to low-frequency channels at th e expense of high-frequency channels, or could not use information in high-frequency channels. The second is that, for diphthongs, patients could not detect frequency change over the course of the utterance. (C ) 1997 Acoustical Society of America.