Temporal dynamics of speech and gesture in Autism Spectrum Disorder

Autism Spectrum Disorder (ASD) is characterized by difficulties in communication and social interaction. Abnormalities in the use of gestures or flow of conversation are frequently reported in clinical observations and contribute to a diagnosis of the disorder but the mechanisms underlying these communication difficulties remain unclear. In the present study, we examine the hypothesis that the temporal dynamics of speech and gesture production is atypical in ASD and affects the overall quality of communication. The context of a previously published study of memory in ASD (Maras et al., 2013) provided the opportunity to examine video recordings of 17 ASD and 17 TD adults attempting to recall details of a standardized event they had participated in (a first aid scenario). Results indicated no group difference in the use and coordination of speech and gesture: both groups produced the same quantity of movement over time (t(33)=-0.165, p>.8), and gestures were produced within the same time window and with a similar distribution by ASD and TD individuals (η²p=.042). Similarly, no group differences were found in the subjective ratings on the quality of communication: in both groups the use of gestures improved comprehension and engagement from the listener. Overall the current data do not suggest that ASD individuals experience more difficulties than TD participants in time processes relevant to communicating personally experienced events. However large inter-individual differences could contribute to communication difficulties in some participants. It will be important for future studies to examine the timing of communicative behaviors during reciprocal interactions, that place demands not only on coordinating speech with gesture but to coordinate one's own behavior with that of others.