Overground Robotic Exoskeleton Gait Training Intensity In Patients With Spinal Cord Injury During Inpatient Rehabilitation

High intensity gait training during inpatient rehabilitation (IPR) promotes functional recovery following spinal cord injury (SCI) and may be achieved with overground robotic exoskeleton gait training (OEGT). Due to neuromuscular and autonomic impairments associated with SCI, assessing intensity through heart rate response and perceived exertion during gait training may be inaccurate. Wearable metabolic systems (WMS) have been used to directly measure intensity using oxygen consumption (VO2) with SCI. However, the use of WMS to assess OEGT intensity during OEGT in IPR is unexplored. PURPOSE: To describe the use of WMS to measure physiological intensity of OEGT in patients with motor incomplete SCI during IPR. METHODS: This observational study included adults aged 18 to 85 admitted to IPR with diagnosis of motor incomplete SCI who were eligible to initiate OEGT. OEGT intensity, duration, and step count were assessed during 1 OEGT session performed within 1 week of gait training initiation following IPR admission. Intensity was assessed by rate of perceived exertion (RPE) and VO2. VO2 was measured using a WMS worn during OEGT and expressed in metabolic equivalents (METs). Moderate and high intensity were defined as ≥3 and ≥ 6 METs, respectively, with 2.7 mL/min/kg of VO2 = 1 MET. RESULTS: 4 participants [3 males; 1 non-Hispanic white, 2 Hispanic white, 1 Black] were aged 52 ± 8.4 years with a body mass index of 28.4 ± 3.2. Participants’ SCI characteristics were 3 diagnosed ASIA Impairment Scale (AIS) C, 1 AIS D; 2 tetraplegia and 2 paraplegia admitted within 30.5 [range = 8-56] days after SCI. Duration of OEGT sessions (n = 4) was 15:57 [range = 10:23-19:43] minutes and participants completed 512 [287-761] steps. RPE was 4 [2-6], VO2 was 7.3 [3.05-15.6], and METs were 2.72 [1.1-5.8]. Three participants achieved ≥3 METs and ≥ 6 METs for 79-89.6% and 4.2-54.8% of the OEGT session, respectively. VO2 was highest in the AIS D participant. CONCLUSIONS: WMS use was demonstrated to feasibly obtain intensity data of OEGT in adults with SCI during IPR. Future research should consider the utility of WMS to assess the capacity of OEGT to promote high-intensity gait training in this population during IPR.