Auditory consonant and word recognition skills of cochlear implant users

Auditory consonant recognition and sentence recognition tests were administered to two subjects wearing the 3M/House cochlear implant, three subjects wearing the 3M/Vienna implant, seven subjects wearing the Cochlear Corporation (Nucleus) implant and 10 subjects wearing the Symbion implant. For the 14-item consonant test, the Symbion subjects scored an average of 41% consonants correct (17-58%), the Cochlear Corporation subjects scored an average of 34% (25-48%), the 3M/Vienna subjects scored 19% (15-26%), and the 3M/House subjects scored 11% (7-14%). An information transfer analysis performed on the consonant data suggested that subjects perceive the envelope feature relatively well and the place feature relatively poorly. All of the 3M/House and 3M/Vienna subjects scored 0% words correct for the sentence test. The Symbion and Cochlear Corporation subjects scored an average of 35% (0-92%) and 32% (9-45%) words correct, respectively. To better understand the variability in word recognition skills, the scores from the sentence test were correlated with the results of the information transfer analysis. The voicing and duration features did not correlate with the sentence scores very well. Place and frication features were shown to be most predictive of auditory word recognition. This finding suggests that subjects who utilize middle and high-frequency speech information are more likely to score better on open-set word recognition tests than subjects who do not.