ABSTRACT
To restore gait function in paraplegic patients, hip-knee-ankle-foot orthoses are available. Orthoses maintain patient stability when standing and walking by restricting the degree of freedom the lower extremity joints. The disadvantages of orthoses include difficulties in standing and sitting movements, and the large burden placed on the upper extremities in walking. Usage of orthoses in daily living was therefore restricted. We are developing a gait assist robot, which we named WPAL (Wearable Power-Assist Locomotor). WPAL has a high degree of freedom and internal power for flexion-extension direction in each hip, knee, ankle joint. We compared WPAL with the conventional Primewalk orthosis as a preliminary investigation. (1) We compared independent standing ability and walking distance of a walker in WPAL and Primewalk orthosis. All three subjects achieved an independent level in standing and walking in WPAL, despite these users requiring assistance when using the Primewalk. Walking distances with the WPAL were several times greater when compared to walking distance with the Primewalk. (2) We performed a single case study using the patient who made the most entries into WPAL exercise. We compared heart rate, physiological cost index (PCI), modified Borg scale, lateral sway of trunk in 6 minutes walking on treadmill. His heart rate, PCI, and modified Borg scale were significantly lower and lateral sway was significantly smaller in WPAL gait. WPAL which has degree of freedom and internal power in the lower extremities is considered a step toward practical powered orthoses use in gait reconstruction for spinal cord injuries.