Mother-Child Biobehavioral Synchrony and Its Association With Social Functioning in Autistic School-Aged Children.

The study was cross-sectional, so it cannot show that synchrony causes better or worse pragmatic language. Only 40 dyads were analysed, and four additional dyads were excluded because of physiological signal artifacts, so the findings may be unstable. The sample was mostly White (63%) and included only mothers, so results may not extend to fathers, other family structures, or cultural contexts. The study was not adequately powered to examine cultural differences. It used one short drawing task and one physiological measure, so the pattern may not hold in other interactions or with other biological indicators. Behavioral synchrony and RSA were measured on different timescales, which makes it difficult to compare the two directly. Friendship quality was measured by parent report, which may not capture the child's own peer relationships. The analysis could not tell whether the mother followed the child's physiology, the child followed the mother's, or both influenced each other.

This work was funded by the University of South Carolina Maternal Child Health Catalyst Program, sponsored by the U.S. Department of Health and Human Services Health Resources and Services Administration, and by a SPARC Graduate Research Grant from the Office of the Vice President for Research at the University of South Carolina. The authors declared no conflicts of interest.

Do not conclude that matching a child's and mother's heart-rate patterns improves language. The study was cross-sectional, and the language link appeared only among dyads already working well together; it did not test a treatment.