Wearable Power-Assist Locomotor (WPAL) for supporting upright walking in persons with paraplegia

BACKGROUND: Due to physical and psychosocial issues associated with long-term sitting in a wheelchair, devising new ways to facilitate upright mobility is a key issue in rehabilitation medicine. Wearable Power-Assist Locomotor (WPAL) is a motorized orthosis and is developed for providing independent and comfortable walking for paraplegic patients. METHODS: The WPAL consists of a wearable robotic orthosis and custom walker. To facilitate alternate usage with a wheelchair, the wearable robotic orthosis is based on a medial system with motors located at the bilateral hip, knee and ankle joints to reduce the increase in heart rate during gait. The gait parameters include stride length, toe clearance height, swing time, double support time, etc. (gait speed: up to 1.3 km/h). Independent gait with the walker can be learned through a five-stage gait exercise sequence. The first two stages are stepping and gait exercises with parallel bars. The third stage is gait exercise on treadmill. The subsequent two stages are gait exercise with walker. RESULTS: Seven motor-complete paraplegic patients (spinal cord functional levels: T6-T12) participated. Through a series of exercises, all users achieved independent gait on a level floor (Functional Ambulation Categories: 4). The mean duration and distance of consecutively walking were 14.1 +/- 11.4minutes and 165.6 +/- 202.6 m, respectively. The most competent user was able to walk continuously for as long as 40 minutes and 640 m whereas only for 6 minutes and 107 m with a conventional orthosis. CONCLUSIONS: These results suggest that WPAL might be useful device for supporting upright walking in persons with paraplegia.