Natural vowel and consonant recognition by Laura cochlear implantees

Objective: This study was performed to examine whether spectral and temporal properties of speech sounds are transferred effectively by the Laura cochlear implant device, and to determine whether listeners with different levels of performance use the same type of information to understand speech. Design: Twenty-five adult Laura cochlear implantees identified 12 repetitions of 10 vowels in /hVt/ utterances and 16 consonants placed in intervocalic /a/ context. The stimulus-response confusion matrices were analyzed in terms of relative information transmission scores (Miller & Nicely, 1955), and they were subjected to multidimensional INDSCAL analyses to examine whether a similar pattern of results would emerge when no prior assumptions were made about the division of categories. Results: To examine perception for different levels of performance, the vowel and consonant confusion data were divided into three groups of subjects: the better, intermediate, and poorer performers. In general, the INDSCAL analyses confirmed the results obtained from the information transmission analyses. However, they also supplemented it with other perceptually relevant cues for cochlear implantees, as web as with the weightings over different perceptual dimensions for different types of performers. These analyses suggest that although all subjects use the same type of information, the better performers are more capable of using these different cues than poor performers.