Mismatch Responses to Prosodic Changes in Children With Developmental Language Disorder: A Longitudinal Approach.

Developmental language disorder is characterized by difficulties in auditory processing and prosody discrimination. Estonian word prosody features a unique three-way quantity distinction, characterized by changes in syllable duration and pitch contour, which differentiate word meaning and grammatical cases. In this study, we examined the Mismatch Responses longitudinally in 23 children with developmental language disorder and 25 age and biological sex matched typically developing peers (age at first measurement 4;6-6;5 years; age at second measurement 5;6-7;5 years). A multifeature paradigm was used in which all stimuli were meaningful words; two deviants differed from the standard, one in syllable duration and the other in both syllable duration and pitch contour. We also tested the discrimination of these prosodic features with behavioral tasks at both measurements. For duration discrimination, an early positive mismatch response diminished from first to second measurement, while a subsequent negative mismatch response increased. Significant longitudinal changes were observed in the typically developing group but not in children with developmental language disorder, while direct comparisons of maturational trajectories did not reveal significant group differences. For the duration and pitch contrast, in both groups and at both assessments, no mismatch response was detected. Additionally, no association was observed at the individual level between maturational changes in mismatch responses and behavioral discrimination at either measurement. These findings provide insights into the maturation of prosodic change detection processes and contribute to a better understanding of developmental language disorder and its manifestations.