Nasalance in Cochlear Implantees

OBJECTIVES Speech intelligibility is severely affected in children with congenital profound hearing loss. Hypernasality is a problem commonly encountered in their speech. Auditory information received from cochlear implants is expected to be far superior to that from hearing aids. Our study aimed at comparing the percentages of nasality in the speech of the cochlear implantees with hearing aid users and also with children with normal hearing. METHODS Three groups of subjects took part in the study. Groups I and II comprised 12 children each, in the age range of 4-10 years, with prelingual bilateral profound hearing loss, using multichannel cochlear implants and digital hearing aids respectively. Both groups had received at least one year of speech therapy intervention since cochlear implant surgery and hearing aid fitting respectively. The third group consisted of age-matched and sex-matched children with normal hearing. The subjects were asked to say a sentence which consisted of only oral sounds and no nasal sounds ("Buy baby a bib"). The nasalance score as a percentage was calculated. RESULTS Statistical analysis revealed that the children using hearing aids showed a high percentage of nasalance in their speech. The cochlear implantees showed a lower percentage of nasalance compared to children using hearing aids, but did not match with their normal hearing peers. CONCLUSION The quality of speech of the cochlear implantees was superior to that of the hearing aid users, but did not match with the normal controls. The study suggests that acoustic variables still exist after cochlear implantation in children, with hearing impairments at deviant levels, which needs attention. Further research needs to be carried out to explore the effect of the age at implantation as a variable in reducing nasality in the speech and attaining normative values in cochlear implantees, and also between unilateral versus bilateral implantees.