Making if-then plans counteracts learned non-use in stroke patients: A proof-of-principle study.

Abstract

After stroke, the learned non-use of a paretic arm is a major obstacle to the improvement of hand function. We examined whether patients with a central paresis could profit from applying the self-regulation strategy of making if-then plans that specify situational triggers to using the paretic arm. Seventeen stroke patients with a mild to moderate hand paresis were asked to perform a Simon task which is commonly used to study the enhanced executive control needed when there is a mismatch between stimulus (e.g., color) and response (e.g., location) features. We examined whether patients with hemiparesis would be able to reduce the Simon effect (i.e., responding slower to mismatched as compared to matched stimulus and response features) by creating new stimulus-response associations via if-then plans. A significant Simon effect was observed in both the affected and the non-affected arm for control trials. However, there was no longer a significant Simon effect for the critical trials prepared by forming if-then plans. This led to a significant stimulus×compatibility interaction effect for the affected arm and a marginally significant interaction effect for the non-affected arm. Making if-then plans was effective for eliminating or at least reducing the Simon effect for the affected and the non-affected arm, respectively. This observation opens a potential new route to improving stroke rehabilitation. If-then plans may qualify as a viable strategy to overcome the learned non-use of the affected arm. Further research is now required to develop and test therapeutic measures based on this proof-of-principle.