AUTHORS: Jeffrey A Brown, MD; Helmi Letsup, MD; Martin Weinand, MD; Steve Cramer, MD

INTRODUCTION: This is a prospective, multi-center safety and effectiveness study of the treatment of patients with hand/arm motor deficit resulting from a stroke at least four months before enrollment with targeted subthreshold cortical stimulation delivered concurrent with rehabilitation.

METHODS: 14 patients were enrolled. 10 patients were randomized to either an investigational group who underwent craniotomy for implantation of an epidural electrode array designed to deliver cortical stimulation concurrent with each rehabilitation session or to a control group who received similar rehabilitation activities only. The electrode array was positioned in the hand/wrist motor cortical region as determined by fMRI images, then projected to a neuronavigational system used to design the craniotomy. All subjects underwent a 16-week protocol that included baseline and weekly evaluations, fMRI, craniotomy for electrode placement (if randomized) and therapy. Safety was evaluated using predetermined criteria of function, seizure occurrence and other medical complications. Efficacy was evaluated weekly for 16 weeks by ten scales focusing on hand strength and function.

RESULTS: Safety criteria were met at 1 and 12 week follow-up. No patients treated according to the investigational plan experienced medical complications. Two infections occurred, one from a surgical protocol violation. In the investigational group statistically significant improvements in hand/arm function were identified in the Arm Motor Fugl-Meyer score (p<0.0001), strength subscore of the Stroke Impact Scale (SIS), Emotion subscore of the SIS (p=0.0002), the SIS Physical Domain (p=0.0007), the NIH Stroke Scale (p=0.0003) and Hand Grip Strength (p=0.0005). Repeated measurement analysis using piecewise linear fits of the two groups showed that the active treatment group improved at a significantly higher rate and to a greater degree on the Arm Fugl-Meyer score than controls (P=0.008).

CONCLUSIONS: Cortical stimulation during three weeks of rehabilitation in stroke patients is safe at 12-week follow-up. Preliminary efficacy evaluation indicates that stimulation improves hand/arm function.

KEYWORDS: motor cortex, electrical stimulation, rehabilitation, stroke

OBJECTIVES: understand the rational for treatment of hemiparetic stroke by cortical stimulation understand whether cortical stimulation for hemiparetic stroke is a safe treatment understand the efficacy of cortical stimulation for hemiparetic stroke