Gesture Comprehension (GeCo) Measure Reveals Deficits in Gesture Processing in Adults with ASD

Background: Diagnostic criteria for autism spectrum disorder (ASD) specify the presence of deficits in the understanding of gesture; however, relatively little research has examined this phenomenon, especially in adults with ASD. One eyetracking study in which gesture information could be utilized to choose which of four available referents was the target reported that the presence of co-speech gesture facilitated language comprehension in adolescents with typical development (TD), but slowed comprehension in adolescents with ASD (Silverman et al., 2010).

Objectives: The current study was designed to examine performance on a novel, ecologically valid measure of gesture comprehension in adults with ASD and TD. We hypothesized that the ASD group would show decreased comprehension.

Methods: Adults with ASD (n = 12) and TD (n = 16) completed an experimental measure of gesture comprehension, the Gesture Comprehension (GeCo) Task. Final sample size will be n=20 per group. Groups did not differ in age (ASD M = 23 years, TD M = 22), or verbal, nonverbal, or full-scale IQ (FSIQ ASD M = 103, TD M = 104; all p’s > 0.39). ASD diagnoses were confirmed by ADOS.

Participants watched a 35-second video of a scripted but naturalistic conversation between two young women discussing a friend’s recent relocation. Immediately after watching the video, they answered 8 questions. Three questions targeted the verbal content of the video (e.g., “When did this event happen?”); five questions targeted information expressed only in gesture (e.g., “What type of staircase was in Sam’s new apartment?”). A correct response to the “staircase” question required that participants integrated information from a gesture, which depicted the spiraling nature of the staircase, with the spoken conversation (“she had to climb up this huge staircase”). The verbal memory questions were designed as a metric of general motivation and attention; the gesture questions were designed to probe participant comprehension of information conveyed solely in gesture. Participants also completed the Digit Span measure of working memory capacity.

Results: Performance was compared between groups. A repeated-measures ANOVA indicated a main effect of group, F(1,26)=12.12, p=0.002, a main effect of measure (verbal memory versus gesture memory), F(1,26)=28.11, p <0.001, and a trend for a group by measure interaction, F(1,26)=4.16, p=0.05. The ASD group had significantly lower scores on gesture comprehension (ASD M = 52%, TD M =78%; F(1,26)=0.08, p =0.003); group differences for the verbal memory items did not differ (ASD M = 61%, TD M =73%; p=0.15). Gesture scores were not correlated with either working memory or ASD symptom severity.

Conclusions: Adults with ASD appeared to have specific difficulty integrating information from gestures, in a novel measure of gesture comprehension, the GeCo. This study extends findings of gesture comprehension deficits in ASD into adulthood. Furthermore, these deficits were apparent when viewing a brief interaction; difficulty understanding gesture is likely even more pronounced during more typical, extended, in-person interactions. This study also highlights the potential utility of the GeCo as a measure of gesture comprehension, a possibility our group will continue to explore.