Robot-Assisted Hand Movement Therapy after Stroke
Robot-Assisted Hand Movement Therapy after Stroke Christopher N. Schabowsky, Ph.D.Director: Peter S. Lum, Ph.D.After therapy intervention, the majority of stroke survivors are left with a poorly functioning hemiparetic hand. Rehabilitation robotics has shown great promise in providing patients with intensive activity-based therapy leading to functional gains. Because of its crucial role in performing activities of daily living, attention to hand therapy has recently increased. This thesis introduces a newly developed Hand Exoskeleton Rehabilitation Robot (HEXORR). This device has been designed to provide full range of motion (ROM) for all of the hand's digits. The thumb actuator allows for variable thumb plane of motion to incorporate different degrees of extension/flexion and abduction/adduction. Compensation algorithms have been developed to improve the exoskeleton's backdrivability by counteracting gravity, stiction and kinetic friction. A force assistance mode has also been designed to provide extension assistance based on each individual's needs. A pilot study was conducted to investigate the device's ability to allow physiologically accurate hand movements throughout the full ROM. The study also tested the efficacy of the force assistance mode with the goal of increasing stroke subjects' active ROM while still requiring active extension movements. The initial stages of a clinical trial providing hand therapy to stroke patients are also discussed.For 12 of the hand digits' 15 joints, there were no significant ROM differences between active extension movements performed inside and outside of HEXORR. For the 1st and 3rd digits, the slopes of joint-pair extension trajectories were no different inside and outside of the device. Stroke subjects were capable of performing hand movements inside of the exoskeleton and the force assistance mode was successful in increasing active ROM by 43% and 22% for the fingers and thumb, respectively. For both subjects, finger and thumb active ROM increased after the conclusion of therapy using HEXORR.Our pilot study shows that this device is capable of moving the hand's digits through the entire ROM with physiologically accurate trajectories. Stroke subjects received the device intervention well and were able to actively extend and flex their digits inside of HEXORR. Our active-assisted condition was successful in increasing the subjects' ROM while generally promoting active participation.
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