Effects of action observation on physical training after stroke

Background and Purpose-In healthy humans, observation of another individual performing a motor training task (action observation [AO]) facilitates, in the observer, the effects of physical training (PT) on motor memory formation. It is not known whether this facilitatory process, of potential value for neurorehabilitation, occurs after stroke. Methods-Eight chronic stroke patients completed this crossover- randomized investigation. A transcranial magnetic stimulation protocol that tests formation of motor memories was used to determine the effects of PT alone and in combination with AO in 2 different forms: congruent (PT + AO(congruent)) and incongruent (PT + AO(incongruent)) to the practiced task. Results-The magnitude of motor memory formation was larger with PT + AO(congruent) than with PT alone or PT + AO(incongruent). This effect was associated with a differential corticomotor excitability change in the muscles acting as agonist and antagonist of the trained/observed movements. Conclusions-These results indicate that congruent AO in association with physical training can enhance the effects of motor training after stroke.