Semantic Processing in Autism During Speech-in-Music Listening: Insights From Congruency and Surprisal-Based N400 Analyses.

Researchers studied how autistic and non-autistic adults process speech when background music is playing. They used brain scans while participants listened to sentences with different types of music. Non-autistic people found it hardest to understand speech with instrumental music and easier with sung lyrics. Autistic participants had more difficulty overall and didn't show the same pattern - they struggled equally whether the sung lyrics were real words or made-up sounds.

This suggests autistic people process speech differently in noisy, musical environments.

This neurophysiological study examined semantic processing during speech-in-music listening in 29 autistic and 29 nonautistic adults using EEG. Participants performed sentence acceptability tasks while listening to music with instrumental, unintelligible (Simlish), or English lyrics. The study analyzed N400 brain responses using both categorical congruency contrasts and continuous lexical surprisal measures. Nonautistic participants showed largest N400 responses with instrumental music and reduced responses with vocals, with accuracy decreasing as lyrics became more intelligible.

Autistic participants demonstrated lower accuracy overall, reduced N400 effects (particularly with instrumental music), and no behavioral differences between English and Simlish conditions, suggesting reduced sensitivity to lyric intelligibility. This provides first neurophysiological evidence of semantic processing differences in autism within ecologically valid auditory environments.

Findings suggest autistic individuals may require additional support in environments with competing auditory information, particularly music with vocals. Results may inform accommodations in educational and therapeutic settings where background music is present, and guide development of targeted interventions for auditory processing challenges.

Single study with modest sample size (n=29 per group). Study type not specified, limiting methodological assessment. No information on participant characteristics, autism diagnostic criteria, or control for confounding variables. Limited to laboratory-based EEG measures rather than real-world assessment.

Understanding speech in background music is a common real-world challenge, particularly when vocals compete for linguistic processing resources. This study examined how the presence and intelligibility of sung lyrics influence semantic processing in autistic and nonautistic adults. Twenty-nine participants per group performed a sentence acceptability judgment task while EEG was recorded. Sentences ended with either semantically congruent or incongruent words and were presented alongside instrumental, Simlish (phonologically English-like but unintelligible), or English-lyric versions of the same songs.

To examine semantic processing, we analyzed the N400 using two complementary approaches: a categorical congruency contrast, indexing the neural cost of processing semantic anomalies, and a continuous lexical surprisal measure, capturing graded sensitivity to word predictability. In nonautistic participants, both analyses showed largest N400 responses in the instrumental condition, attenuated responses in vocal conditions, and reduced behavioral accuracy as lyrics became more intelligible. Autistic participants showed lower accuracy and a reduced N400 effect relative to nonautistic participants, particularly in the instrumental music condition. In addition, they exhibited no behavioral difference between the English and Simlish vocal conditions, suggesting that changes in lyric intelligibility did not affect accuracy.

By combining ecologically valid speech-in-music masking with dual analytic approaches, this study provides the first neurophysiological evidence of these semantic processing differences in autism and demonstrates how integrating categorical and probabilistic measures can yield a richer and more nuanced account of speech processing in complex auditory environments.