Aberrant gesture use in autism spectrum disorders is unrelated to motor abnormalities.

Background:  Gesture deficits are well-documented in youth with autism spectrum disorder (ASD), yet research in adults with ASD remains limited. Understanding the nature of gesture deficits in adulthood is essential for identifying their underlying mechanisms and potential impact on communication and daily functioning. The aim of the current study examines gesture performance in adults with ASD to explore whether these deficits persist beyond childhood and how they relate to motor impairments.

Methods:  We included 19 patients diagnosed with ASD and 19 age-and-gender matched controls. Gesture performance accuracy was assessed in both groups using the Test of Upper Limb Apraxia (TULIA) which was subjectively rated according to the manual by an independent single rater who was blinded to the group allocations, while manual dexterity was assessed using the performance-based coin-rotation task. We further assessed motor impairments in patients using standardized well-established motor scales to examine their potential contributions to gesture accuracy.

Results:  Individuals with ASD exhibited significant gesture deficits compared to controls, while manual dexterity remained preserved. Tool-based gestures appeared to be the most affected. Though ASD individuals exhibited numerous motor impairments they were not associated with gesture deficits.

Conclusions:  Our findings suggest that gesture deficits in ASD are not driven by the presence of motor impairments. However, given the small sample size, these results should be interpreted with caution. Future studies with larger and more diverse samples are needed to further investigate the mechanisms contributing to gesture difficulties in ASD.