White matter and speech timing in autism (Davison et al., 2025)

Purpose: Converging research suggests that speech timing, including altered rate and pausing when speaking, can distinguish autistic individuals from nonautistic peers. Although speech timing can impact effective social communication, it remains unclear what mechanisms underlie individual differences in speech timing in autism.

Method: The present study examined the organization of speech- and language-related neural pathways in relation to speech timing in autistic and nonautistic children (24 autistic children, 24 nonautistic children [ages: 5–17 years]). Audio recordings from a naturalistic language sampling task (via narrative generation) were transcribed to extract speech timing features (speech rate, pause duration). White matter organization (as indicated by fractional anisotropy [FA]) was estimated for key tracts bilaterally (arcuate fasciculus, superior longitudinal fasciculus [SLF], inferior longitudinal fasciculus [ILF], frontal aslant tract [FAT]).

Results: Results indicate associations between speech timing and right-hemispheric white matter organization (FA in the right ILF and FAT) were specific to autistic children and not observed among nonautistic controls. Among nonautistic children, associations with speech timing were specific to the left hemisphere (FA in the left SLF).

Conclusion: Overall, these findings enhance understanding of the neural architecture influencing speech timing in autistic children and, thus, carry implications for understanding potential neural mechanisms underlying speech timing differences in autism.

Supplemental Material S1. Between-group comparisons of fractional anisotropy values for each white matter pathways examined in the present study.

Davison, K. E., Liu, T., Belisle, R. M., Perrachione, T. K., Qi, Z., Gabrieli, J. D. E., Tager-Flusberg, H., & Zuk, J. (2025). Right-hemispheric white matter organization is associated with speech timing in autistic children. Journal of Speech, Language, and Hearing Research, 68(6), 2685–2699. https://doi.org/10.1044/2025_JSLHR-24-00548