Perceptual Development of Nasal Consonants in Children With Normal Hearing and in Children Who Use Cochlear Implants

Purpose: This study was conducted to determine whether the perceptions of nasal consonants in children with normal hearing and children with cochlear implants were predicted by the discontinuity hypothesis. Methods: Four groups participated: 8 adults, 8 children with normal hearing (ages 5-7 years), 8 children with normal hearing (ages 3.5-4 years), and 5 children with cochlear implants (ages 5-7 years). Stimuli were 128 nasal consonant + vowel (/m//n/ + /i//ae// u//a/) syllables produced by a male adult. Each syllable production was edited into 4 segment types: (a) 50-ms murmur, (b) 25-ms murmur + 25-ms transition, (c) 50-ms transition, and (d) full syllable. Results: Developmental effects were observed across listener groups. The children performed better in the 25-ms murmur + 25-ms transition condition, which suggests that they benefit from an integrated perceptual cue. The children wearing cochlear implants performed poorer than children with normal hearing on all segments. Conclusions: Developmental differences in perception of nasal consonants were evident. Children wearing cochlear implants showed weaker integration and perception abilities compared to younger children with normal hearing. As predicted by the discontinuity hypothesis, the segment with the spectral discontinuity provided the strongest perceptual cues to place of articulation of nasals in children with normal hearing.