Brain reorganization after bilateral arm training and distributed constraint-induced therapy in stroke patients: A preliminary functional magnetic resonance imaging study

Background: Bilateral arm training (BAT) and constraint-induced therapy (CIT) have shown beneficial effects in improving motor control and function of the upper extremities (UE) for patients with stroke. Thus far, no study has directly investigated the relative effects of BAT versus CIT on brain reorganization. This study compared the effects of BAT with distributed CIT (dCIT) on brain reorganization and motor function in 6 stroke patients. Methods: In a pre-post randomized controlled trial, 6 stroke patients received BAT (intensive bilateral simultaneous and symmetrical training) or dCIT (restraint of the unaffected UE combined with intensive training of the affected UE) for a period of 3 weeks, 5 days per week. Functional magnetic resonance imaging (fMRI) examination and 3 clinical measures (Fugl-Meyer Assessment, Action Research Arm Test, and Motor Activity Log) were administered before and after the intervention. Results: After intervention, patients showed varied patterns of fMRI changes and improved motor function. Two well-recovered patients, one from each group, showed large increases in bilateral hemisphere activation, especially in the ipsilesional hemisphere during affected hand movement and in the contralesional hemisphere during unaffected hand movement. During bilateral elbow movement, 3 of the 4 BAT patients showed increased bilateral cerebellum activation, especially in the left cerebellum, whereas 2 dCIT patients showed decreased cerebellar activation. Conclusions: The findings of this preliminary research revealed that neuroplastic changes after stroke motor rehabilitation may be specific to the intervention. Further research using a larger sample and more complex fMRI tasks is warranted to validate the findings.