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