Comparison of energy efficiency between Wearable Power-Assist Locomotor (WPAL) and two types of knee-ankle-foot orthoses with a medial single hip joint (MSH-KAFO).

OBJECTIVE: To compare the energy efficiency of Wearable Power-Assist Locomotor (WPAL) with conventional knee-ankle-foot orthoses (MSH-KAFO) such as Hip and Ankle Linked Orthosis (HALO) or Primewalk. STUDY DESIGN: Cross over case-series. SETTING: Chubu Rosai Hospital, Aichi, Japan, which is affiliated with the Japan Organization of Occupational Health and Safety. METHODS: Six patients were trained with MSH-KAFO (either HALO or Primewalk) and WPAL. They underwent 6-minute walk tests with each orthosis. Energy efficiency was estimated using physiological cost index (PCI) as well as heart rate (HR) and modified Borg score. Trial energy efficiency with MSH-KAFO was compared with WPAL to assess if differences in PCI became greater between MSH-KAFO and WPAL as time goes on during the 6-minute walk. Spearman correlation coefficient of time (range: 0.5-6.0 minutes) with the difference was calculated. The same statistical procedures were repeated for HR and modified Borg score. RESULTS: Greater energy efficiency, representing a lower gait demand, was observed in trials with WPAL compared with MSH-KAFO (Spearman correlation coefficients for PCI, HR and modified Borg were 0.93, 0.90 and 0.97, respectively, all P < 0.0001). CONCLUSIONS: WPAL is a practical and energy efficient type of robotics that may be used by patients with paraplegia.

Clinical feasibility of gait training with a robotic exoskeleton (WPAL) in an individual with both incomplete cervical and complete thoracic spinal cord injury: A case study.

BACKGROUND: Patients with tetraplegia can achieve independent gait with lateral-type powered exoskeletons; it is unclear whether medial-type powered exoskeletons allow for this. OBJECTIVE: To investigate gait training with a medial-type powered exoskeleton wearable power-assist locomotor (WPAL) in an individual with incomplete cervical (C5) and complete thoracic (T12) spinal cord injury (SCI). METHODS: The 60-session program was investigated retrospectively using medical records. Upon completion, gait performance was examined using three-dimensional motion analyses and surface electromyography (EMG) of the upper limbs. RESULTS: The subject achieved independent gait with WPAL and a walker in 12 sessions. He continuously extended his right elbow; his left elbow periodically flexed/extended. His pelvic inclination was larger than the trunk inclination during single-leg stance. EMG activity was increased in the left deltoid muscles during ipsilateral foot-contact. The right anterior and medial deltoid muscle EMG activity increased just after foot-off for each leg, as did the right biceps activity. Continuous activity was observed in the left triceps throughout the gait cycle; activity was unclear in the right triceps. CONCLUSIONS: These results suggest the importance of upper limb residual motor function, and may be useful in extending the range of clinical applications for robotic gait rehabilitation in patients with SCI.