Noise and a Speaker's Impaired Voice Quality Disrupt Spoken Language Processing in School-Aged Children: Evidence from Performance and Response Time Measures.

Purpose Our aim was to investigate isolated and combined effects of speech-shaped noise (SSN) and a speaker's impaired voice quality on spoken language processing in first-grade children. Method In individual examinations, 53 typically developing children aged 5–6 years performed a speech perception task (phoneme discrimination) and a listening comprehension task (sentence–picture matching). Speech stimuli were randomly presented in a 2 × 2 factorial design with the factors noise (no added noise vs. SSN at 0- dB SNR) and voice quality (normal voice vs. impaired voice). Outcome measures were task performance and response time (RT). Results SSN and impaired voice quality significantly lowered children's performance and increased RTs in the speech perception task, particularly when combined. Regarding listening comprehension, a significant interaction between noise and voice quality indicated that children's performance was hindered by SSN when the speaker's voice was impaired but not when it was normal. RTs in this task were unaffected by noise or voice quality. Conclusions Results suggest that speech signal degradations caused by a speaker's impaired voice and background noise generate more processing errors and increased listening effort in young school-aged children. This finding is vital for classroom listening and highlights the importance of ensuring teachers' vocal health and adequate room acoustics.