Training-induced changes of motor cortex representations in stroke patients

Objective - To study changes in motor cortex representations after a single session of physiotherapy in stroke patients. Methods - TMS mapping was used to evaluate the motor output map of the abductor pollicis brevis (APB) in both hemispheres. Stroke patients (4-8 weeks after the infarction) were studied prior to a training session aimed at improving dexterity and 1 h and 1 day after the training. Results - Prior to the training, the APE representation area in the affected hemisphere was significantly smaller than on the non-affected side. After therapy, the cortical motor output to the paretic APE was significantly enlarged, and motor function was improved. One day later, these effects were partially reversed. Motor thresholds remained significantly increased in the affected hemisphere before and after the therapy. Conclusion - A single session of physiotherapy produces a use-dependent enlargement of motor cortex representations paralleled by an improvement of motor function in stroke patients.