The Use of Static and Dynamic Cues for Vowel Identification by Children Wearing Hearing Aids or Cochlear Implants

To examine vowel perception based on dynamic formant transition and/or static formant pattern cues in children with hearing loss while using their hearing aids or cochlear implants. We predicted that the sensorineural hearing loss would degrade formant transitions more than static formant patterns, and that shortening the duration of cues would cause more difficulty for vowel identification for these children than for their normal-hearing peers.

A repeated-measures, between-group design was used. Children 4 to 9 years of age from a university hearing services clinic who were fit for hearing aids (13 children) or who wore cochlear implants (10 children) participated. Chronologically age-matched children with normal hearing served as controls (23 children). Stimuli included three naturally produced syllables (/ba/, /bi/, and /bu/), which were presented either in their entirety or segmented to isolate the formant transition or the vowel static formant center. The stimuli were presented to listeners via loudspeaker in the sound field. Aided participants wore their own devices and listened with their everyday settings. Participants chose the vowel presented by selecting from corresponding pictures on a computer screen.

Children with hearing loss were less able to use shortened transition or shortened vowel centers to identify vowels as compared to their normal-hearing peers. Whole syllable and initial transition yielded better identification performance than the vowel center for /ɑ/, but not for /i/ or /u/.

The children with hearing loss may require a longer time window than children with normal hearing to integrate vowel cues over time because of altered peripheral encoding in spectrotemporal domains. Clinical implications include cognizance of the importance of vowel perception when developing habilitative programs for children with hearing loss.