Each year approximately 795,000 individuals in the United States experience a debilitating stroke with up to 75% of the survivors suffering significant residual upper limb motor impairments. Previous research has shown that individuals with a hemiparetic stroke demonstrate spasticity (i.e., hyperactive stretch reflexes), weakness, and loss of independent joint control of their paretic arm, drastically decreasing quality of life. The impairments stem from a loss of corticospinal projections giving rise to an increased reliance on bulbospinal pathways. Increased reliance on the alternative pathways results in increased excitatory motor drive to the wrist and finger flexors when the paretic arm is lifted (loss of independent joint control) and the inability to effectively activate the extensor muscles (weakness), which together make opening of the hand exceedingly difficult. Previous research studies at the ankle and elbow joints have demonstrated that these types of neurologic deficits also lead to chronic, secondary changes in the muscles, increasing passive torques and stiffness. While not previously documented in the complex wrist and hand musculoskeletal system following stroke, such adaptations could further reduce the ability to open the hand and extend the wrist even as the neural deficits diminish over time. However, current rehabilitation methods to improve hand function in individuals with chronic stroke focus primarily on the neural deficits, with limited success, and neglect the negative effects of potential increased passive torques due to musculoskeletal adaptations. Therefore in order to improve current rehabilitation methods it is imperative to understand how potential increases in the passive properties of hand post stroke may contribute to hand impairments separate from the active neural deficits. Thus, the goal of this study is to determine the relative contributions to impaired hand opening post stroke due to altered passive torque and stiffness (muscle adaptations) versus deficits of neural origin (abnormal flexor drive and extensor weakness). This knowledge allows for the development of more effective and targeted rehabilitation approaches to improve outcomes and the quality of life for individuals post stroke.
|Effective start/end date||7/1/16 → 6/30/18|
- American Heart Association Midwest Affiliate (16PRE30970010//MWA Winter 2016)