Nasalance in typically developing children and in children with hearing impairment

Abstract

This study compared the effects of vowels and CV combinations on nasalance scores in children with and without hearing impairment using Nasometer II Model 6400. The eect of voicing on nasalance scores was also analyzed. Fifteen children with normal hearing and fteen with hearing impairment in the age range of 3 to 7 years participated in the study. The subjects were instructed to repeat isolated vowels (/a/, /i/, /u/) and CV combinations (phonemes /p/, /t/, /k/, /b/, /d/ and /g/ with vowels /a/, /i/ and /u/) at their habitual rate. The mean nasalance value was extracted. Independent samples t-test showed a signicant dierence in the nasalance values across vowels in both the groups. High nasalance value was seen for high anterior vowel /i/ followed by /a/ and /u/. Both unvoiced and voiced bilabial, dental and velar consonants with /i/ had high nasalance value followed by /u/ and /a/ in the both groups. This is attributed to the valving function of velopharyngeal closure during the articulation of /i/. Children with hearing impairment had signicantly higher mean nasalance values when compared to children with normal hearing owing to the lack of auditory feedback, essential to maintain the oral/nasal distribution. The results also showed that voiced consonants had higher nasalance values than their unvoiced counterparts. The outcome of the present study would aid Speech Pathologists in developing appropriate stimuli for assessing velopharyngeal closure for children with hearing impairment.