Cortical stimulation for the rehabilitation of patients with hemiparetic stroke: a multicenter feasibility study of safety and efficacy

Abstract

Object: In this prospective multicenter study the authors hypothesized that investigational epidural cortical stimulation (CS) delivered concurrently with rehabilitation therapy may enhance motor recovery following stroke.

Methods: Patients who had suffered their index stroke >or= 4 months previously were randomized into 6 weeks of rehabilitation therapy with or without CS. Cortical stimulation, targeted by functional imaging, was delivered at approximately 50% of motor movement threshold. Primary outcome measures were Upper Extremity Fugl-Meyer (UEFM [a measure of neurological and motor function]) and Arm Motor Ability Test (AMAT [a measure of activities of daily living]) scores. The primary study end point was 4 weeks following rehabilitation therapy.

Results: A total of 24 patients, 12 per group, completed the treatment protocol. The mean interval since the patients' index stroke was 33 months (range 4-100 months). There were no deaths or cases of neurological deterioration; 1 acute postoperative seizure occurred unrelated to the device or treatment. Patients who underwent CS experienced improved hand/arm function more than control patients. The UEFM score improved 5.5 +/- 4.4 points in patients in the CS group compared with 1.9 +/- 4.4 points for controls (p = 0.03). A 3.5-point UEFM improvement is considered clinically meaningful. The AMAT scores for the CS group improved by 0.4 +/- 0.6 points, whereas the scores in the control group improved by 0.2 +/- 0.4 points (p = 0.2). A 0.21-point improvement in AMAT score is considered clinically meaningful. In the CS group, 67% of patients had clinically meaningful improvement in UEFM scores, compared with 25% of the control group (p = 0.05). Of patients in the CS group 50% had clinically meaningful improvement in UEFM as well as AMAT scores, compared with only 8% of those in the control group (p = 0.03).

Conclusions: These results suggest that subthreshold epidural CS is safe and effective during rehabilitation for recovery of arm and hand function following hemiparetic stroke. Further research in a larger cohort is needed to validate the therapeutic effect.