Modulating brain plasticity in rehabilitation of stroke and other brain lesions

National Institute Of Neurological Disorders And Stroke

Investigators

Linked publications, trials & patents

Abstract

Background: Disability resulting from stroke and traumatic brain injury represent the main causes of long-term complications in adults. There are no universally accepted treatments available to treat these conditions and the financial, personal, familial and social cost of these disabilities cannot be underestimated. Preliminary data from different laboratories have shown that it is possible to modulate plastic processes in the lesioned brain via pharmacological, or brain and somatosensory stimulation techniques. The purpose of this project is to identify mechanisms of stroke motor disability and characterize the most promising techniques to improve cortical plasticity in these patients to enhance functional recovery. Findings this year: During the past year, results from a successful clinical trial collaboration were published in the Journal of Neurorehabilitation and Neural Repair. The aim of the clinical trial was to investigate the efficacy of repetitive peripheral nerve sensory stimulation (RPSS) as an adjuvant therapy to motor training in stroke rehabilitation. We tested the hypothesis of whether 3 h sessions of real RPSS paired with functional electrical stimulation (FES) and task-specific training (TST) resulted in more beneficial outcomes to improve upper limb motor function compared with sham RPSS in addition to FES and TST, in stroke patients with moderate to severe hand motor impairments at least 6 months after the stroke event. In this single-center, randomized, placebo controlled, parallel-group, double-blind study we compared the effects of 18 therapy sessions (administered three times per week, over a total of 6 weeks) involving either active or sham RPSS as add-on interventions to FES and task-specific training of the paretic upper limb. The study cohort included 40 chronic stroke patients (defined as having experienced an ischemic or hemorrhagic stroke event at least 6 months earlier) with Fugl-Meyer upper limb scores ranging from 7 to 50. All participants were able to voluntarily perform some level of wrist extension. The primary outcome measure was the Wolf Motor Function Test (WMFT) administered after all 18 therapy sessions (i.e. - 6 weeks of therapy) were completed. Several secondary outcome measures included (1) WMFT scores, (2) a motor activity log, (3) active range of motion of wrist extension and flexion, (4) grasp and pinch strength in the paretic and non-paretic sides, (5) Modified Ashworth Scale, (6) Fugl-Meyer Assessment-Upper Limb in the paretic arm (7) Barthel Index and (8) Stroke Impact Scale. All secondary outcome measures were evaluated at 3 (i.e. - therapy mid-point). Results for this time-point were reported. We also plan to evaluate secondary outcomes at 10 (i.e. - one month after therapy concluded), and 18 weeks after beginning of treatment (i.e. - 3 months after therapy concluded) to determine longer-lasting effects of the intervention. Our current results revealed that WMFT scores were significantly improved in both active and sham RPSS groups at 3 and 6 weeks of treatment. Patients receiving active RPSS also displayed significantly improved grasp strength at 3 and 6 weeks although the sham RPSS group did not. Both active and sham RPSS displayed significant improvements in pinch strength at 3 weeks, while only the active RPSS group showed extended pinch strength gains at 6 weeks. Data obtained from the 10 and 18 week time-points will be needed to determine if these elevated grasp and pinch strength gains for the active RPSS group extend beyond the duration of the therapy. Still, our results implicate repetitive peripheral nerve sensory stimulation as an effective adjuvant therapy for improving clinical outcomes in stroke rehabilitation. (Trial Registration: NCT02658578).