Visuo-motor imitation (VMI) impairments are central to the pathogenesis and affect the treatment of autism spectrum disorders (ASD). Therapies most commonly used to enhance social, communicative, academic, adaptive and occupational function in individuals with ASD rely on imitation, and impairments in VMI represent a bottleneck to the efficiency and efficacy of these therapies.
Furthermore, an influential psychological account suggests that imitation impairments lead to the development of the ASD phenotype. By studying precisely how VMI is impaired in ASD, we have the potential both to enhance widespread therapies and possibly to alter the course of the disorder itself. Unfortunately, we currently know little about the precise nature of imitation impairments in ASD. Our laboratory has recently identified a promising specific task parameter that separates preserved from impaired gesture imitation in ASD: children with ASD have difficulty imitating when the task requires two separate movement elements be coordinated simultaneously. By contrast, imitation is relatively preserved when movement elements are performed serially. This finding has been subsequently validated in multiple datasets. Coordination of simultaneous movements is a hallmark of skills performed in the real world (shoe tying, eating with knife-and-fork, driving, communicating with simultaneous verbal and gestural language). In order to optimize common adaptive and social-communicative skill therapies, the next step is to tease apart where, in the chain from perception to action, the capacity limitation in simultaneous processing lies.