Principal Investigator: Carolynn Patten, PhD, PT Investigators: George Chen, PhD; Ilse Jonkers, PhD; Abigail M. Andrade, BS PTA; and Christine A. Dairaghi, BS Project Category: - 2005 Objective: The overriding goal of this proposal is to identify the critical physiological and biomechanical effects of BWSTT for promoting improved locomotor function in persons with post-stroke hemiparesis. We hypothesize that key differences are present in both biomechanical (i.e., loading, kinetic energy at toe off, trunk energetic cost, muscle tendon lengthening velocity) and physiological (i.e., temporal patterning of intermuscular EMG, central reflex modulation) constituents of locomotion between internally and externally-driven modes of BWSTT. Externally-driven BWSTT (Lokomat) produces a more controlled, consistent and mechanically appropriate locomotor pattern promoting positive adaptation in the spinal locomotor circuitry and improved integration of descending motor drive which in combination promote improved gait dynamics. These therapeutically-induced differences will be manifest in the ability to generalize the effects of BWSTT to overground locomotion and will include: improved gait symmetry, increased knee flexion during swing phase, normalization of limb kinetic energy at the stance-to-swing transition, and the ability to scale gait speed effectively between self-selected and fast speeds. We further hypothesize that externally-driven BWSTT will produce more persistent treatment-related effects. Research Plan and Methods: In this pilot study, we will conduct a series of twelve single-case, ABA or BAB, designs in which hemiparetic subjects will experience both internally and externally-driven BWSTT. Training parameters (i.e., body weight support, treadmill speed and support stiffness) will be held constant between modes of BWSTT and physiological and biomechanical responses will be compared between modes for individual subjects. Adaptations in overground gait parameters (i.e., limb kinetic energy at toe off, knee flexion, trunk mechanical energetic cost, gait symmetry, gait speed) will be compared using reference normal gait data obtained from non-disabled, age and gender-matched control subjects walking at matched speeds. The response of non-disabled control subjects to both forms of BWSTT will also be studied. Clinical Relevance to the VA: Stroke represents a major public health problem in the United States today. Over 700,000 persons suffer first time strokes each year. Due to advances in acute medical management, the survivor cohort now exceeds 4.8 million persons in the U.S. Over two-thirds of these individuals experience profound physical disability including impaired locomotor function. Among their most frequently articulated rehabilitation goals is to improve walking ability. Progress Report and Findings to Date: This project was approved and funding was initiated in August 2005. Research Plan for the Next Year: Development of data acquisition techniques and treatment protocols is underway. Pilot testing with patients has begun with the goal of initiating the treatment phase of this project in the next few weeks. Patient treatment and assessment will continue throughout this year. Funding Source: VA RR&D Merit Review Funding Status: Active
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