Spaciousness as an acoustic measure of prosody in autistic children.

Distinctive prosody has been reported in autism, yet acoustic studies have yielded inconsistent findings, particularly for F0-related measures. Two dynamic measures, spaciousness (magnitude of pitch excursions) and wiggliness (rate of pitch-direction changes), offer alternatives, but spaciousness has not yet been applied to English-speaking autistic children. The present study therefore compared acoustic characteristics of prosody from autistic and language-skill matched nonautistic children (age 3-7) using spaciousness, wiggliness, F0 measures (mean, standard deviation, and range), and speech rate. Linear mixed-effects models revealed that only spaciousness showed significant group differences, and these differences were independent of utterance length. Replication in larger samples is warranted.