Action observation produces motor resonance in Parkinson's disease

Abstract

Observation of movement activates the observer's own motor system, influencing the performance of actions and facilitating social interaction. This motor resonance is demonstrated behaviourally through visuomotor priming, whereby response latencies are influenced by the compatibility between an intended action and an observed (task‐irrelevant) action. The impact of movement disorders such as Parkinson's disease (PD) on motor resonance is unclear, as previous studies of visuomotor priming have not separated imitative compatibility (specific to human movement) from general stimulus‐response compatibility effects. We examined visuomotor priming in 23 participants with mild‐to‐moderate PD and 24 healthy older adults, using a task that pitted imitative compatibility against general stimulus‐response compatibility. Participants made a key press after observing a task‐irrelevant moving human finger or rectangle that was either compatible or incompatible with their response. Imitative compatibility effects, rather than general stimulus‐response compatibility effects, were found specifically for the human finger. Moreover, imitative compatibility effects did not differ between groups, indicating intact motor resonance in the PD group. These findings constitute the first unambiguous demonstration of imitative priming in both PD and healthy ageing, and have implications for therapeutic techniques to facilitate action, as well as the understanding of social cognition in PD.

Efficacy and Characteristics of the Stimuli of Action Observation Therapy in Subjects With Parkinson's Disease: A Systematic Review

“…The characteristics of AOT stimuli vary across the included studies with some research suggesting an association between features of video-clips and AOT efficacy (11). Studies have described additional benefits when AOT is associated with motor imagery in both healthy subjects and patients with neurological disorders (40)(41)(42)(43). However, none of the studies administering AOT in subjects with PD took into account the association between AOT and motor imagery.…”

Action Imagery and Observation in Neurorehabilitation for Parkinson’s Disease (ACTION-PD): Development of a User-Informed Home Training Intervention to Improve Functional Hand Movements

“…AO and MI have shown promising effects in neurorehabilitation [24][25][26]. In a small number of laboratory studies in people with PD, AO influenced movement speed and timing in reaching [27] and finger-tapping [28] tasks, as well as hand movement amplitude [29], and preserved motor resonance for incidentally observed hand actions has been found in PD [30]. People with PD also report similar vividness of MI to healthy controls; however, like their actual movements, their imagery may be slowed [31], and compensatory mechanisms may be involved [32,33].…”

Action Imagery and Observation in Neurorehabilitation for Parkinson’s Disease (ACTION-PD): development and pilot randomised controlled trial of a user-informed home training intervention to improve everyday functional actions

“…Moreover, MI training is recommended in rehabilitation guidelines from the American Stroke Association [31]. Although a smaller number of studies have investigated AO and MI in PD, AO has been found to influence movement speed and timing in reaching [32] and finger-tapping [33] tasks, as well as hand movement amplitude [34], and people with PD have shown preserved motor resonance for incidentally-observed hand actions [35]. People with PD also report similar vividness of MI to healthy controls; however, like their actual 3 movements their imagery may be slowed [36], and compensatory mechanisms may be involved, such as a greater reliance on visual processes [37,38].…”