Acoustic and perceptual appraisal of speech production in pediatric cochlear implant users

Objective: The purpose of the present study was to examine the relationship between objectively measurable acoustic changes in speech production and subjective speech production accuracy and perceived intelligibility immediately following a disruption in auditory feedback normally provided to subjects from a cochlear implant. Methods: Six children with profound sensorineural hearing loss participated in the study. Their task was to produce speech samples in two conditions: (1) with auditory feedback from their cochlear implants, and (2) without auditory feedback from their cochlear implants. Samples were subjected to both objective and subjective analyses. Objectively, measures were made of duration, fundamental frequency, and the first and second formants of the vowels. Subjectively, two groups of listeners, one familiar with the speech of children with hearing loss and the other unfamiliar, transcribed the productions and provided ratings of intelligibility. Results: All the children in this study exhibited significant differences from the cochlear implant-on to the cochlear implant-off condition, although these changes were not always in the predicted direction, nor were they always perceptually salient. Conclusions: Consistent with previous studies, children in this investigation demonstrated variable acoustic voice and speech changes following deactivation of their cochlear implant device. Few of these acoustic changes affected speech intelligibility. The results of this study overall suggest that during the initial years following implantation children who are deaf rely to some extent on the auditory feedback provided by a cochlear implant to control and modify F0, duration, and vowel formant production.