ABSTRACT
BACKGROUND: Lower extremity robotic exoskeleton technology is being developed with the promise of affording people with spinal cord injury (SCI) the opportunity to stand and walk. The mobility benefits of exoskeleton-assisted walking can be realized immediately, however the cardiorespiratory and metabolic benefits of this technology have not been thoroughly investigated. OBJECTIVE: The purpose of this pilot study was to evaluate the acute cardiorespiratory and metabolic responses associated with exoskeleton-assisted walking overground and to determine the degree to which these responses change at differing walking speeds. METHODS: Five subjects (4 male, 1 female) with chronic SCI (AIS A) volunteered for the study. Expired gases were collected during maximal graded exercise testing and two, 6-minute bouts of exoskeleton-assisted walking overground. Outcome measures included peak oxygen consumption (VÌO2peak), average oxygen consumption (VÌO2avg), peak heart rate (HRpeak), walking economy, metabolic equivalent of tasks for SCI (METssci), walk speed, and walk distance. RESULTS: Significant differences were observed between walk-1 and walk-2 for walk speed, total walk distance, VÌO2avg, and METssci. Exoskeleton-assisted walking resulted in %VÌO2peak range of 51.5% to 63.2%. The metabolic cost of exoskeleton-assisted walking ranged from 3.5 to 4.3 METssci. CONCLUSIONS: Persons with motor-complete SCI may be limited in their capacity to perform physical exercise to the extent needed to improve health and fitness. Based on preliminary data, cardiorespiratory and metabolic demands of exoskeleton-assisted walking are consistent with activities performed at a moderate intensity.
Subject(s)
Energy Metabolism/physiology , Exoskeleton Device , Heart Rate/physiology , Oxygen Consumption/physiology , Spinal Cord Injuries/rehabilitation , Adult , Chronic Disease , Female , Humans , Male , Middle Aged , Physical Fitness/physiology , Pilot Projects , Spinal Cord Injuries/physiopathology , Walking/physiologyABSTRACT
This paper presents preliminary results on the development of a powered lower limb orthosis intended to provide legged mobility (with the use of a stability aid, such as forearm crutches) to paraplegic individuals. The orthosis contains electric motors at both hip and both knee joints, which in conjunction with ankle-foot orthoses, provides appropriate joint kinematics for legged locomotion. The paper describes the orthosis and the nature of the controller that enables the SCI patient to command the device, and presents data from preliminary trials that indicate the efficacy of the orthosis and controller in providing legged mobility.
