Constraint-induced therapy in stroke: magnetic-stimulation motor maps and cerebral activation

Constraint-induced movement therapy (CI), a standardized intensive rehabilitation intervention, was given to patients a year or more following stroke. The goal was to determine if CI was more effective than a less-intensive control intervention in changing motor function and/or brain physiology and to gain insight into the mechanisms underlying this recovery process. Subjects were recruited and randomized more than 1 year after a single subcortical infarction. Clinical assessments performed before and after the intervention and at 6 months postintervention included the Wolf Motor Function Test (WMFT), the Motor Activity Log (MAL), and the Assessment of Motor and Process Skills (AMPS). Transcranial magnetic stimulation was used to map the motor cortex. Positron emission tomography was used to measure changes in motor task-related activation due to the intervention. MAL increased by 1.08 after CI therapy and decreased by 0.01 after control therapy. The difference between groups was significant (P < 0.001). Changes in WMFT and AMPS were not significantly different between groups. Cerebral activation during a motor task decreased significantly, and motor map size increased in the affected hemisphere motor cortex in CI patients but not in control patients. Both changes may reflect improved ability of upper motor neurons to produce movement.