Acquisition of voice onset time in toddlers at high and low risk for autism spectrum disorder.
Karen Chenausky, Helen Tager-Flusberg
PMID 28339140WHAT IT FOUND
Toddlers at high risk for autism produced similar words, errors, and speech timing as controls.
At 36 months, children with autism were less likely to make measurably separate /b/ and /p/ sounds. This was a small speech difference, not a tested treatment effect.
Key findings
01The groups did not differ in the number of words they produced or the number of speech errors they made.
02The average voice onset time for /p/ sounds increased with age, but the groups did not differ on this measure.
03At 36 months, toddlers with autism had lower odds of producing measurably separate /b/ and /p/ voice onset time populations than low-risk controls.
STILL TO COME
How it was doneWhat they foundWhat it means for SLPs
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What it does not show
The sample was small: 55 toddlers, including 33 high-risk siblings. The paper describes the participants as language-normal, so findings may not apply to toddlers with more severe language or autism. The study used a limited age range, from 18 to 36 months. Speech came from spontaneous samples during assessment visits while children could move, not from controlled elicited words, so variability was higher than in lab-based studies. Some children did not produce any /b/ or /p/ words at some ages, so not every child contributed data at every age. The 36-month finding was one of several analyses and needs replication in a larger high-risk sibling sample. The study did not test whether the acoustic difference affected intelligibility, whether parents asked for clarification, or whether treatment changes the outcome.
The easy way to misread this
Do not conclude that autism causes a general speech delay or that voice onset time is a ready clinical marker. Most speech measures did not differ by group, and the only significant group-related result was an association at 36 months in whether /b/ and /p/ populations were measurably separate. The study did not test treatment or intelligibility.