Motor Recovery and Cortical Reorganization after Constraint-Induced Movement Therapy in Stroke Patients: A Preliminary Study

Abstract

Constraint-induced movement therapy (CIMT) is a physical rehabilitation regime that has been previously shown to improve motor function in chronic hemiparetic stroke patients. However, the neural mechanisms supporting rehabilitation-induced motor recovery are poorly understood. The goal of this study was to assess motor cortical reorganization after CIMT using functional magnetic resonance imaging (fMRI). In a repeated-measures design, 4 incompletely recovered chronic stroke patients treated with CIMT underwent motor function testing and fMRI. Five age-matched normal subjects were also imaged. A laterality index (LI) was determined from the fMRI data, reflecting the distribution of activation in motor cortices contralateral compared with ipsilateral to the moving hand. Pre-intervention fMRI showed a lower LI during affected hand movement of stroke patients (LI = 0.23+/-0.07) compared to controls (LI unaffected patient hand = 0.65+/-0.10; LI dominant normal hand = 0.65+/-0.11; LI nondominant normal hand = 0.69+/-0.11; P < 0.05) due to trends toward increased ipsilateral motor cortical activation. Motor function testing showed that patients made significant gains in functional use of the stroke-affected upper extremity (detected by the Motor Activity Log) and significant reductions in motor impairment (detected by the Fugl-Meyer Stroke Scale and the Wolf Motor Function Test) immediately after CIMT, and these effects persisted at 6-month follow-up. The behavioral effects of CIMT were associated with a trend toward a reduced LI from pre-intervention to immediately post-intervention (LI = -0.01+/-0.06, P = 0.077) and 6 months post-intervention (LI = -0.03+/-0.15). Stroke-affected hand movement was not accompanied by mirror movements during fMRI, and electromyographic measures of mirror recruitment under simulated fMRI conditions were not correlated with LI values. These data provide preliminary evidence that gains in motor function produced by CIMT in chronic stroke patients may be associated with a shift in laterality of motor cortical activation toward the undamaged hemisphere.

Plasticity in the developing brain: Implications for rehabilitation

“…Voxel-based comparisons also showed significant changes in the anterior supplementary motor area contralateral to the motor deficit. This is the first study of structural changes in gray matter of cerebral cortex after constraint-based therapy, and the results complement previous data using functional methods (TMS mapping, PET, and fMRI) to document cortical changes following the procedure [Liepert et al, 2000;Schaechter et al, 2002;Wittenberg et al, 2003]. The results of the study highlight the importance of combining a behavioral intervention with the functional activity task and constraint of the better arm to produce functional improvement and structural change in the brain.…”

Increased Perfusion in Motor Areas after Constraint-Induced Movement Therapy in Chronic Stroke: A Single-Photon Emission Computerized Tomography Study

“…The increase in the healthy hemisphere may also suggest bilateral participation of primary motor cortices in voluntary movement execution after the therapy. Increased ipsilateral motor cortex involvement in movement execution has been reported after CIMT in stroke patients (Schaechter et al, 2002).…”

Volition and Imagery in Neurorehabilitation

“…[1][2][3][4][5][6] One limitation of training protocols is that patients with more profound weakness are unable to carry out the motor routines required. The finding that passively elicited motions lead to activation and cortical reorganization in brain regions common to those activated with performance of voluntary movements suggested that it could also elicit improvements in motor function.…”