PERFORMANCE OF ADULT INERAID AND NUCLEUS COCHLEAR IMPLANT PATIENTS AFTER 3.5 YEARS OF USE

Forty-two postlingually deafened adult patients, 21 with a formant ext raction version of the Nucleus cochlear implant and 21 with the Inerai d cochlear implant (analog processing), were evaluated on a series of speech perception tests after using their implants for about 3.5 years . A wide range of performance was observed across patients for both de vices. All but 4 patients showed an enhancement in their lipreading ab ility with the implant. Word recognition averaged about 14-19% correct and word recognition in sentences averaged about 43-49% correct for t he two implant groups. Average performance was superior with the Inera id implant on consonant recognition in noise. An information transmiss ion analysis suggested that vowel perception was influenced by first- and third-formant frequency for the Nucleus, and first-formant and fun damental frequency for the Ineraid patients. It appeared that the Iner aid device was more effective, on average, at conveying information ab out consonant nasality and frication. For consonant perception, nasali ty and frication contributed most to the total information transmitted for both implant types. Both devices had difficulty conveying informa tion about vowel second-formant frequency and consonant place informat ion. These scores at 3.5 years are substantially elevated from preoper ative performance and, overall, the patients clearly benefit from thei r implant.