Atypical perceptual and neural processing of emotional prosodic changes in children with autism spectrum disorders.

OBJECTIVE: The present study explored the processing of emotional speech prosody in school-aged children with autism spectrum disorders (ASD) but without marked language impairments (children with ASD [no LI]). METHODS: The mismatch negativity (MMN)/the late discriminative negativity (LDN), reflecting pre-attentive auditory discrimination processes, and the P3a, indexing involuntary orienting to attention-catching changes, were recorded to natural word stimuli uttered with different emotional connotations (neutral, sad, scornful and commanding). Perceptual prosody discrimination was addressed with a behavioral sound-discrimination test. RESULTS: Overall, children with ASD (no LI) were slower in behaviorally discriminating prosodic features of speech stimuli than typically developed control children. Further, smaller standard-stimulus event related potentials (ERPs) and MMN/LDNs were found in children with ASD (no LI) than in controls. In addition, the amplitude of the P3a was diminished and differentially distributed on the scalp in children with ASD (no LI) than in control children. CONCLUSIONS: Processing of words and changes in emotional speech prosody is impaired at various levels of information processing in school-aged children with ASD (no LI). SIGNIFICANCE: The results suggest that low-level speech sound discrimination and orienting deficits might contribute to emotional speech prosody processing impairments observed in ASD.

Impaired neural discrimination of emotional speech prosody in children with autism spectrum disorder and language impairment.

Autism spectrum disorders (ASD) are characterized by deficient social and communication skills, including difficulties in perceiving speech prosody. The present study addressed processing of emotional prosodic changes (sad, scornful and commanding) in natural word stimuli in typically developed school-aged children and in children with ASD and language impairment. We found that the responses to a repetitive word were diminished in amplitude in the children with ASD, reflecting impaired speech encoding. Furthermore, the amplitude of the MMN/LDN component, reflecting cortical discrimination of sound changes, was diminished in the children with ASD for the scornful deviant. In addition, the amplitude of the P3a, reflecting involuntary orienting to attention-catching changes, was diminished in the children with ASD for the scornful deviant and tended to be smaller for the sad deviant. These results suggest that prosody processing in ASD is impaired at various levels of neural processing, including deficient pre-attentive discrimination and involuntary orientation to speech prosody.