Repetitive bilateral arm training and motor cortex activation in chronic stroke: a randomized controlled trial

Abstract

Context: Reorganization in central motor networks occurs during early recovery from hemiparetic stroke. In chronic stroke survivors, specific rehabilitation therapy can improve upper extremity function.

Objective: To test the hypothesis that in patients who have chronic motor impairment following stroke, specific rehabilitation therapy that improves arm function is associated with reorganization of cortical networks.

Design, setting, and patients: A randomized controlled clinical trial conducted in a US ambulatory rehabilitation program with 21 patients (median [IQR], 50.3 [34.8-77.3] months after unilateral stroke). Data were collected between 2001 and 2004.

Interventions: Patients were randomly assigned to bilateral arm training with rhythmic auditory cueing (BATRAC) (n = 9) or standardized dose-matched therapeutic exercises (DMTE) (n = 12). Both were conducted for 1 hour, 3 times a week, for 6 weeks.

Main outcome measures: Within 2 weeks before and after the intervention, brain activation during elbow movement assessed by functional magnetic resonance imaging (fMRI) and functional outcome assessed using arm function scores.

Results: Patients in the BATRAC group but not in the DMTE group increased hemispheric activation during paretic arm movement (P = .03). Changes in activation were observed in the contralesional cerebrum and ipsilesional cerebellum (P = .009). BATRAC was associated with significant increases in activation in precentral (P<.001) and postcentral gyri (P = .03) and the cerebellum (P<.001), although 3 BATRAC patients showed no fMRI changes. Considering all patients, there were no differences in functional outcome between groups. When only BATRAC patients with fMRI response were included (n = 6), BATRAC improved arm function more than DMTE did (P = .02).

Conclusions: These preliminary findings suggest that BATRAC induces reorganization in contralesional motor networks and provide biological plausibility for repetitive bilateral training as a potential therapy for upper extremity rehabilitation in hemiparetic stroke.

Figure 1

Participant Flow Through the Trial BATRAC indicates bilateral arm training with rhythmic auditory cueing; DMTE, dose-matched therapeutic exercises; fMRI, functional magnetic resonance imaging. *In a secondary analysis on arm function data, 3 patients without fMRI response were excluded.

Figure 2

fMRI Images Before and After Intervention (All Patients) During Motion of the Paretic Arm Two axial sections at different z coordinates representing changes of activation are shown. Areas of yellow-orange indicate increased activation after bilateral arm training with rhythmic auditory cueing (BATRAC); areas of green would indicate increased activation in control patients but none were detected (probability threshold P < .05, corrected for multiple comparisons). In neither group were any areas of decreased activation identified after the intervention. Left panel, Talairach coordinates x, y, z (foci from anterior to posterior): contralesional: −5/4/61 (Brodmann area [BA] 6), −17/−7/61 (BA 6), −15/−60/61 (BA 7); ipsilesional: 12/14/61 (BA 6), 13/−13/61 (BA 6). Right panel, ipsilesional: 29/−77/−29 (posterior lobe of cerebellum). DMTE indicates dose-matched therapeutic exercises (control).

Figure 3

Functional Magnetic Resounance Images Representing the Difference in Activation in Each Patient Undergoing BATRAC Lesions are on the right side of the brain, probability threshold P < .001, uncorrected; green-blue indicates decreased activation; yellow-orange, increased. A-F, In 6 of 9 patients, increased activation was seen in the precentral and postcentral gyri (orange-yellow). In a few cases (blue) there was decreased activation. G-I, In 3 patients there was no change in activation of precentral, postcentral, or premotor areas. BATRAC indicates bilateral arm training with rhythmic auditory cueing.