Mechanisms of Upper-Extremity Motor Recovery in Post-stroke Hemiparesis

Mechanisms of Upper-Extremity Motor Recovery in Post-stroke Hemiparesis

The results of this study will provide sound, scientific evidence of physiologic mechanisms responsible for upper-extremity weakness; evidence of the processes involved in neuromuscular adaptation; and will elucidate the relationship between impairment and motor disability in post-stroke hemiparesis.

This proposal extends the work accomplished in our initial study (project #B2405R, 'Effects of Strength Training on Upper-limb Function in Post-stroke Hemiparesis'). In the present study we will conduct a double-blind, randomized clinical trial of staged rehabilitation for the upper-extremity involving sequential delivery of functional therapy and high intensity resistance training. Therefore, this proposal directly compares the effects of functional and resistance training delivered individually. The researchers' previous work investigated a hybrid therapy of functional and resistance training against functional training alone. All subjects will participate in a 5 week run-in period of no treatment. This no-treatment block will afford multiple baseline measurements and, in addition, will provide information regarding the rate and magnitude of any spontaneous recovery without treatment. Following the second baseline measurement, all subjects will be randomized to upper-extremity rehabilitation in either: Order A - 10 weeks of functional task practice training (FTP) followed by 10 weeks of high-intensity resistance training (Power) or Order B - resistance training (Power) followed by FTP. Re-evaluation will occur following each block of treatment,and retention effects will be evaluated after 6 and 12 months with no additional treatment. Subjects will be evaluated with: outcome measures used broadly in Clinical Neurology and Rehabilitation, a battery of biomechanical performance measures including: strength, muscle activation, reflex modulation, and motor coordination, and with kinematics of free reaching movements. The researchers will investigate persons in the intermediate phase of recovery which they define as between 6 and 18 months post-stroke , having completed all inpatient and outpatient therapies, with remaining residual motor deficits.

Inclusion Criteria:

• Clinical diagnosis of cerebrovascular accident
• Single event
• Unilateral hemiplegia
• Between 6 months and 18 months post-event
• Impairment of upper-extremity function
• Ability to produce partial range of motion out of plane of gravity at shoulder, elbow, and wrist
• At least 10 degrees of wrist motion (any 10 degrees), and finger flexion/extension in 2 fingers
• Cognitive ability to follow 3-step commands

Exclusion Criteria:

• Unstable or uncontrolled blood pressure
• Uncontrolled seizures
• Flaccid hemiplegia
• Severe cognitive impairment