Validity of Vocal Communication and Vocal Complexity in Young Children with Autism Spectrum Disorder.

The validation applies to these specific vocal variables, uses, and population. It may not transfer to other vocal measures, other purposes, or other children. Many significance tests were done without alpha adjustment. This increases the risk of false positives, although composites partially reduce that concern. The vocal communication and vocal complexity variables were not always cleanly separable. For example, DKCC combines communication and complexity. The study was correlational and used a single-group pre-post analysis. It cannot show that vocal measures cause language outcomes or that treatment caused the changes. Participants were selected from a trial sample. They were 13 to 30 months old at entry, spoke English at least 60% of the time at home, were ambulatory without hand-use motor impairment, had a developmental quotient of at least 35, and had normal hearing and vision screening. The paper used research coding of play samples. It does not show that these variables can be coded live reliably in clinics without training.

SR has potential conflicts related to publications about interventions used in this study, for which she receives royalties. All royalties from those publications were donated to autism research. JM, PY, and AE declared no conflict of interest. JM conceived and drafted the study, PY was a site principal investigator, and AE and SR were principal investigators on the overarching study.

Do not read these findings as proof that a therapy that increases vocal communication or vocal complexity will improve expressive language. The study measured associations and change in one group over time. It did not test whether treatment caused the changes.