Automatic Imitation of Hand Movements in Clinical and Neurodiverse Populations

Automatic imitation is related to both motor and social-cognitive processes and hence is highly relevant to a range of clinical and neurodiverse populations including neurodegenerative, psychiatric or mental health, and neurodevelopmental conditions. In this chapter, we review investigations of automatic imitation of hand and arm movements in these populations. For many of the conditions reviewed, there are relatively small numbers of studies in the literature and/or existing studies only include relatively small participant numbers. There is, however, some evidence for intact automatic imitation in several conditions (Parkinson’s, Alzheimer’s, depression, autism). If automatic imitation is unimpaired, motor and behavioral interventions have the potential to capitalize on this. There are, however, reports from one or two studies of increased automatic imitation in schizophrenia and mirror-touch synesthesia and reduced automatic imitation in eating disorders, which warrant further investigation. The evidence in developmental coordination disorder and Tourette’s is more mixed. Moreover, altered top-down modulation of automatic imitation has been found in several studies of autism and in one study of schizophrenia. We discuss some of the methodological issues, such as the importance of the stimuli and instructions used in the tasks, as well as considering other factors such as co-morbidities. There are also challenges in accounting for reaction time differences and a range of analysis approaches, which ought to be constrained by pre-registered analysis plans in future research. Future studies ought to investigate top-down modulation in other conditions since this process is key to successful motor and social function.