Optimizing Contralaterally Controlled FES for Acute Upper Limb Hemiplegia

Loss of arm and hand function is a severely disabling condition that occurs in nearly 75% of the estimated 795,000 Americans who have a new or recurrent stroke each year [Roger 2011]. Upper limb impairment is often characterized by inability to extend the elbow and open the hand. The hope of regaining lost motor function after stroke has been fueled in recent years by the development of new rehabilitation therapies and devices that are aimed at promoting the brain's capacity to reorganize after injury in such a way that restores motor control of paretic limbs [Nudo 2001]. The Investigators' long-term objective is to develop stroke rehabilitation treatments for the hemiparetic upper limb that are optimized for effectiveness, applicability, and deployability. The primary objective of this project is to estimate the effect of Arm+Hand Contralaterally Controlled Functional Electrical Stimulation (CCFES) in reducing upper limb motor impairment and activity limitation in subacute hemiplegia. CCFES is a treatment aimed at improving recovery of volitional motor function in stroke survivors [Knutson 2007; Knutson 2009; Knutson 2010]. Hand CCFES activates finger and thumb extensors with an intensity of electrical stimulation that is proportional to the degree of opening of the contralateral unimpaired hand wearing an instrumented glove. Thus, volitional opening of the nonparetic hand produces stimulated opening of the paretic hand. The Hand CCFES system enables stroke patients to use their impaired hand to practice functional tasks in therapy sessions. CCFES incorporates the following features considered to be important to motor recovery and promoting neuroplasticity: synchronization of motor intent with motor execution of paretic hand opening [Rushton 2003; Kimberley 2004], bilateral symmetric movement [Luft 2004], intensive repetitive hand opening exercises [Lang 2009], and the practice of functional tasks [Nudo 2003]. In a pilot case series study of patients with chronic (> 6 months) post-stroke hemiplegia, all 6 participants experienced some reduction of upper limb motor impairment after several weeks of Hand CCFES [Knutson 2007; Knutson 2009]. The results of a Phase I randomized clinical trial (RCT) of Hand CCFES in 21 patients with subacute (≤ 6 months) hemiplegia suggested that Hand CCFES may be superior to cyclic neuromuscular electrical stimulation (NMES) in reducing upper extremity impairment and activity limitation [Knutson 2011]. In this study, added to the Hand CCFES treatment is stimulated elbow extension controlled by the contralateral elbow. This "next generation" CCFES treatment is called Arm+Hand CCFES. Arm+Hand CCFES therapy is intended to strengthen and improve the motor control of the proximal upper limb as well as the hand, to improve simultaneous reaching and hand opening, a functionally critical movement pattern that is often prevented by paresis and post-stroke flexor synergies. The secondary objective of this project is to evaluate the effect of adding elbow extensor stimulation to the Hand CCFES treatment. Stroke survivors who are ≤ 2 years post-stroke with upper limb hemiplegia will be randomly assigned to receive 12 weeks of either Arm+Hand CCFES (stimulates elbow extension and hand opening), Hand CCFES (stimulates hand opening), or Arm+Hand Cyclic NMES (stimulates elbow extension and hand opening but with pre-set timing and intensity, i.e., not intention-driven), plus lab-based therapist-guided task practice. Upper limb impairment and activity limitation will be assessed at baseline, 6, 12, 20, 28, and 36 weeks. This is the first randomized controlled trial of Arm+Hand CCFES in subacute upper extremity hemiplegia. Ultimately, the information learned in this study will serve to accelerate the development of a new treatment for reducing post-stroke disability.