Combined Visual Feedback with Pelvic Assistance Force Improves Step Length during treadmill walking in Individuals with Post-Stroke Hemiparesis.

Abstract

Altered spatiotemporal gait characteristics are common impairments after stroke. Visual feedback has been used to improve spatiotemporal gait characteristics. In addition, pelvic assistance force applied in the mediolateral direction to the paretic side can improve walking pattern. Potentially, combined visual feedback and pelvic assistance force can have better rehabilitation outcomes on walking patterns. The purpose of this study was compare the effects of combined visual feedback with pelvic assistance force and visual feedback only during treadmill walking in individuals with post-stroke hemiparesis. Fifteen subjects with hemiparesis due to chronic (>6 months) stroke participated. A computer monitor placed in front of the treadmill was used to provide visual feedback on subjects' weight bearing on the paretic leg. A customized cabledriven robotic system was used to apply pelvic assistance force. The magnitude of pelvic assistance force was 9% of body weight. The session consisted of 5 sections: 1-min baseline, 7-min treadmill training (visual feedback only or combined visual feedback and pelvic assistance force), 1-min post-training (no visual feedback or pelvic assistance force), 1-min standing break, and 5-min treadmill training. The order of the visual feedback only and combined visual feedback and pelvic assistance force sessions was randomized across subjects. Spatiotemporal gait variables within the session, including stance time, single leg support time and step length, were computed. Combined visual feedback with pelvic assistance force resulted in a better improvement in step length of the paretic leg when compared to visual feedback only (p=0.03). Walking patterns after stroke could potentially be improved by applying visual feedback regrading paretic leg weight bearing and pelvic assistance force. Future study is needed to confirm the effectiveness of visual feedback for treadmill training after stroke.