ALTERATIONS IN JOINT KINEMATICS FOLLOWING LOCOMOTOR TRAINING IN INDIVIDUALS WITH CHRONIC STROKE

Abstract

Purpose/Hypothesis: Locomotor retraining is an important component of stroke rehabilitation. Evidence suggests that, even in chronic stages post-stroke, improvements in ambulatory capacity can be realized with task-specific, intensive rehabilitation strategies. The practice of locomotor training using a motorized treadmill and providing body weight support (BWS) has been shown to improve walking ability in subjects with neurological injury, and is used increasingly in the clinical setting. However, most gains reported are specific to temporal-spatial parameters (gait speed, symmetry) with little information regarding the ability of locomotor retraining paradigms to alter kinematic patterns following chronic stroke. While therapists are unable to offer consistent kinematic movements, the use of robotic exoskeletons for locomotor retraining can provide many correct sensory cues related to bipedal locomotion in a repeatable, consistent manner to potentially enhance learning and promote improved kinematics. The purpose of this study was to determine if locomotor retraining using either therapist- or robotic-assistance could induce changes in walking kinematics. Number of Subjects: Twenty ambulatory subjects with hemiplegia following chronic stroke (>; 6 mo.) were recruited and randomly allocated to locomotor training on a treadmill using BWS using either therapist- or robotic assistance. Materials/Methods: Training was performed 3X/week for 30min/session over 4 weeks. Progression consisted of increasing gait speed to 3.0km/hr and then gradually reducing BWS as tolerated. Computerized gait analysis was performed at the subject's self-selected walking speed prior to and following the training. Subjects were allowed to walk with their least restrictive assistive devices during testing, although devices were removed during training. 3D joint angles were calculated at the hip, knee, and ankle using rigid body analysis and compared between sessions for each group. Results: Both groups demonstrated increased gait speed following training (p<;0.05), although preliminary analysis indicates no substantial changes in gait kinematics were observed in either group. Conclusions: These data suggest that despite improvements in temporal-spatial characteristics, only small changes are observed in gait kinematics. It is possible that due to the chronic nature of the stroke longer term training is required to evoke changes in walking kinematics. The robotic exoskeleton is purported to improve walking patterns via the delivery of appropriate sensory cues. The fact that the robotic assistance did not improve gait to a greater extent than therapist-assisted training suggests that repetition of similar patterns is no more effective at improving kinematics than the more variable therapist assisted training. Additional training and/or combined therapies may be needed to “normalize” kinematics patterns following chronic stroke. Clinical Relevance: Patients, even years after the incident stroke, can improve gait through intensive training, although only small changes to kinematic parameters are observed.