Differences in Acute Metabolic Responses to Bionic and Nonbionic Ambulation in Spinal Cord Injured Humans and Controls.

OBJECTIVES: To (1) compare energy expenditure during seated rest, standing, and prolonged bionic ambulation or bipedal ambulation in participants with spinal cord injury (SCI) and noninjured controls, respectively, and (2) test effects on postbionic ambulation glycemia in SCI. DESIGN: Two independent group comparison of SCI and controls. SETTING: Academic Medical Center. PARTICIPANTS: Ten participants with chronic SCI (C7-T1, American Spinal Injury Association Impairment Scale A-C) and 10 controls (N=20). INTERVENTIONS: A commercial bionic exoskeleton. MAIN OUTCOME MEASURES: Absolute and relative (to peak) oxygen consumption, perceived exertion, carbohydrate/fat oxidation, energy expenditure, and postbionic ambulation plasma glucose/insulin. RESULTS: Average work intensity accompanying 45 minutes of outdoor bionic ambulation was <40% peak oxygen consumption, with negligible drift after reaching steady state. Rating of perceived exertion (RPE) did not differ between groups and reflected low exertion. Absolute energy costs for bionic ambulation and nonbionic ambulation were not different between groups despite a 565% higher ambulation velocity in controls and 3.3× higher kilocalorie per meter in SCI. Fuel partitioning was similar between groups and the same within groups for carbohydrate and fat oxidation. Nonsignificant (9%) lowering of the area under a glucose tolerance curve following bionic ambulation required 20% less insulin than at rest. CONCLUSION: Work intensity during prolonged bionic ambulation for this bionic exoskeleton is below a threshold for cardiorespiratory conditioning but above seated rest and passive standing. Bionic ambulation metabolism is consistent with low RPE and unchanged fuel partitioning from seated rest. Bionic ambulation did not promote beneficial effects on glycemia in well-conditioned, euglycemic participants. These findings may differ in less fit individuals with SCI or those with impaired glucose tolerance. Observed trends favoring this benefit suggest they are worthy of testing.

Exoskeleton gait training after spinal cord injury: An exploratory study on secondary health conditions.

OBJECTIVE: To explore changes in pain, spasticity, range of motion, activities of daily living, bowel and lower urinary tract function and quality of life of individuals with spinal cord injury following robotic exoskeleton gait training. DESIGN: Prospective, observational, open-label multicentre study. METHODS: Three training sessions per week for 8 weeks using an Ekso™ GT robotic exoskeleton (EKSO Bionics). Included were individuals with recent (<1 year) or chronic (>1 year) injury, paraplegia and tetraplegia, complete and incomplete injury, men and women. RESULTS: Fifty-two participants completed the training protocol. Pain was reported by 52% of participants during the week prior to training and 17% during training, but no change occurred longitudinally. Spasticity decreased after a training session compared with before the training session (p <0.001), but not longitudinally. Chronically injured participants increased Spinal Cord Independence Measure (SCIM III) from 73 to 74 (p = 0.008) and improved life satisfaction (p = 0.036) over 8 weeks of training. Recently injured participants increased SCIM III from 62 to 70 (p < 0.001), but no significant change occurred in life satisfaction. Range of motion, bowel and lower urinary function did not change over time. CONCLUSION: Training seemed not to provoke new pain. Spasticity decreased after a single training session. SCIM III and quality of life increased longitudinally for subsets of participants.

Clinician-Focused Overview of Bionic Exoskeleton Use After Spinal Cord Injury.

Spinal cord injury (SCI) resulting in paralysis of lower limbs and trunk restricts daily upright activity, work capacity, and ambulation ability, putting persons with an injury at greater risk of developing a myriad of secondary medical issues. Time spent in the upright posture has been shown to decrease the risk of these complications in SCI. Unfortunately, the majority of ambulation assistive technologies are limited by inefficiencies such as high energy demand, lengthy donning and doffing time, and poor gait pattern precluding widespread use. These limitations spurred the development of bionic exoskeletons. These devices are currently being used in rehabilitation settings for gait retraining, and some have been approved for home use. This overview will address the current state of available devices and their utility.