Limits of locomotor ability in subjects with a spinal cord injury

Abstract

Case-control study with pair-wise matching. To investigate the level of locomotor performance in spinal cord injury (SCI) subjects. Spinal Cord Injury Center of Balgrist University Hospital in Zurich, Switzerland. Seven well-recovered SCI subjects and controls performed three tests: (1) 6-Min Walk Test (6MWT), (2) treadmill walking with full and restricted vision and (3) repetitive stepping over an obstacle. In the latter task, the subjects had to step over an obstacle as low as possible, without touching it. The subjects performed three blocks of 50 trials each. They received acoustic signals that indicated obstacle approach and foot clearance. During the third block, vision was restricted. The main outcome measures were: (1) distance walked, (2) leg muscle activity, joint kinematics and double-support duration, (3) foot clearance, number of obstacle hits, leg muscle activity, joint kinematics and swing phase duration. (1) No difference in the 6MWT between the groups. (2) Independent from vision, the double-support duration was increased in SCI subjects. (3) SCI subjects learned generally at a slower rate. They touched the obstacle more frequently when vision became restricted. Furthermore, we observed differences between the groups in rectus femoris and tibialis anterior EMG activity and swing phase duration. It appears that even in well-recovered SCI subjects, small deficiencies in functional gait can be determined, which remain undetected by clinical walking tests. In addition, SCI subjects learned a locomotor task at a slower rate. This indicates that rehabilitation programs should train (adaptive) locomotion in different (sensory) environments.