Does observation of a disabled child's action moderate action execution? Implication for the use of Action Observation Therapy for patient rehabilitation.

Background: Research investigating action observation-execution priming has mainly manipulated congruent versus incongruent action, and aspects of action expertise/capability. More specifically, the literature suggests enhanced performance priming following action observation by actors closely matched to participant expertise. The aim of the present study was to extend the understanding of action expertise effects by investigating action priming in healthy participants after observing a mild hemiparetic child actor versus a neurologically healthy child actor.

Methods: 16 healthy right-handed children, aged 6-13 years were tested. Several motor assessments were performed, including gross and fine manual motor ability, and upper limb kinematics measured using a precise robotic device. A cross-over design consisted in two experimental conditions (observing actions performed by a child with hemiparesis versus observing actions performed by a healthy child) and a pre-observation double baseline control condition, with the data analyzed using repeated measures ANOVA.

Results: Relative to baseline, both types of action observation conditions enhanced fine manual dexterity, but observing the hemiparetic child enhanced gross manual dexterity and upper limb velocity kinematics relative to observing actions performed by a healthy child. No effects were shown on measures of smoothness and accuracy.

Discussion: Contradictorily to hypotheses discussed in the literature, results here showed evidence of enhanced action execution when healthy children observed hemiparetic compared to healthy child actions. These results are discussed in terms of how patient compared to healthy actors may be useful for clinical action observation priming therapy.