Background: Gait analysis studies during robot-assisted walking have been predominantly focused on lower limb biomechanics. During robot-assisted walking, the users' interaction with the robot and their adaptations translate into altered gait mechanics. Hence, robust and objective metrics for quantifying walking performance during robot-assisted gait are especially relevant as it relates to dynamic stability. In this study, we assessed bi-planar dynamic stability margins for healthy adults during robot-assisted walking using EksoGT™, ReWalk™, and Indego® compared to independent overground walking at slow, self-selected, and fast speeds. Further, we examined the use of forearm crutches and its influence on dynamic gait stability margins. Methods: Kinematic data were collected at 60 Hz under several walking conditions with and without the robotic exoskeleton for six healthy controls. Outcome measures included (i) whole-body center of mass (CoM) and extrapolated CoM (XCoM), (ii) base of support (BoS), (iii) margin of stability (MoS) with respect to both feet and bilateral crutches. Results: Stability outcomes during exoskeleton-assisted walking at self-selected, comfortable walking speeds were significantly (p < 0.05) different compared to overground walking at self-selected speeds. Unlike overground walking, the control mechanisms for stability using these exoskeletons were not related to walking speed. MoSs were lower during the single support phase of gait, especially in the medial–lateral direction for all devices. MoSs relative to feet were significantly (p < 0.05) lower than those relative to crutches. The spatial location of crutches during exoskeleton-assisted walking pushed the whole-body CoM, during single support, beyond the lateral boundary of the lead foot, increasing the risk for falls if crutch slippage were to occur. Conclusion: Careful consideration of crutch placement is critical to ensuring that the margins of stability are always within the limits of the BoS to control stability and decrease fall risk.

The goal of this study is to dynamically assess the posture and balance of individuals with spinal cord injury and able-bodied controls during robotic-assisted gait, using the EksoGT™ and ReWalk™, by examining their 3-D whole body, trunk and lower-extremity CoM excursions and their sagittal trunk lean angle during baseline and post-training (>100 hours). At baseline, there were strong differences (p<0.05) between the devices where CoM excursions, root-mean-squared-errors between the trunk and lower-extremity CoMs and a trend for significance in trunk lean angle were much greater in the ReWalk™ than EksoGT™. These differences further increased post-training, particularly in the EksoGT™.

In persons with spinal cord injury (SCI), paralysis results in extreme physical inactivity and a higher percent of body fat. The accumulation of excess fat in the visceral cavity is a primary contributor to metabolic abnormalities and an increased risk of cardiovascular disease (CVD), one of the leading causes of death in the SCI population. Powered exoskeleton-assisted walking (EAW) are robotic devises that promote exercise through rehabilitation and overground walking that may have positive effects on body composition and cardiometabolic health. The purpose of this prospective observational study was to determine changes in total body fat mass (TBFmass), total body fat percent (TBF%), android adipose tissue percent (AAT%), visceral adipose tissue percent (VAT%), and subcutaneous adipose tissue percent (SAT%) after 100 sessions of powered EAW in persons with chronic SCI. This prospective single arm intervention study was performed in 8 participants with chronic SCI (>12 months). Participants trained in a robotic exoskeleton (Ekso, Ekso Bionics, Richmond, CA, USA) with each loading session lasting 1-hour, 3-4 times a week, for a total of 100 1-hour sessions. Measures of TBF, TBF%, AAT%, VAT%, and SAT% were obtained prior to training (PRE) and immediately after 100 sessions of EAW (POST) using dual energy x-ray absorptiometry (DXA, GE Lunar iDXA, enCore and CoreScan, platform version 14.0, Madison, WI). Paired t-tests were performed to determine significant differences in the absolute pre-post values and the a priori level of significance was set at p<0.05. Compared to the PRE training values, adiposity POST training was significantly decreased in TBF (pre vs. post: 28.7 ± 7.3 vs. 26.5 ± 7.5 kg, p<0.05), TBF% (pre vs. post: 37.9 ± 5.4 vs. 35.6 ± 5.3%, p=0.02), AAT% (pre vs. post: 9.0 ± 1.1 vs. 8.4 ± 1.0 %, p=0.02), and SAT% (pre vs. post: 4.8 ± 1.9 vs. 4.3 ± 2.0 %, p<0.05); there was with a small nonsignificant decrease in VAT% (pre vs. post: 3.7 ± 2.5 vs. 3.6 ± 2.3 %, p=ns). EAW training provided sufficient energy expenditure to reduce total body adiposity and most of the measures of central adiposity. Decreased adiposity would be expected to be associated with reduced risk of metabolic syndrome and CVD.

Objective: To describe the impact of an education program to prevent falls in full-time manual wheelchair users (MWU) living with Spinal Cord Injury (SCI).Design: Pre/post.At baseline, participants reported the frequency of falls over the past six months and completed the Community Participation Indicators(CPI) and the World Health Organization Quality of Life (short version -WHO-QOL BREF) assessment.Transfer quality to and from a mat table was assessed using the Transfer Assessment Instrument (TAI) and boundaries of seated stability were evaluated using standardized procedures.After baseline testing, a structured education program designed to decrease fall frequency was implemented.After the intervention, participants were asked to prospectively track fall frequency for 12 weeks.After 12 weeks, the assessment, as described above, was repeated.Participant/methods: 18 fulltime MWUs with SCI participated in the study.Participants were an average of 35.78 ± 13.89 y.o. and lived with their SCI for an average of 17 ± 15 years.The majority of participants were female (n = 11, 61.1%).Level of injury ranged from C4-L3, AIS A-C.To examine the differences in outcomes pre and post exposure to the education program, seated stability was evaluated using a paired t-test.Nonparametric Wilcoxon tests were used to evaluate all other variables due to the ordinal or non-normally distributed nature of the data.Results: After exposure to the intervention, fall frequency significantly decreased, (Pre: 1.37 ± 1.62 falls per month, Post: 0.67 ± 0.82, p = 0.047).A trend in the data indicated improvements in seated stability (Pre: 1.22 ± .26,Post: 1.35 ± .26,p = 0.06).Finally, significant improvements were found in the Post: 75.61 ± 16.38 p = 0.05) and Psychological (Pre: 69.06 ± 14.67, Post: 76.17 ± 17.62, p = 0.040) domains.No significant differences were found among TAI or CPI scores. Conclusion:The structured fall prevention education program specifically designed for MWUs living with SCI appears to have potential to reduce fall frequency and improve quality of life.Additional research in the form of a large-scale, controlled investigation of the program is needed to further assess program effectiveness.

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The goal of this study was to establish strideparameter gait models correlated to speed on individuals with chronic SCI and able-bodied controls walking with a powered robotic exoskeleton (EksoGT $^{\mathrm{ TM}}$). Longitudinal exoskeleton training $( >100$ hours) across eight individuals with SCI resulted in a 30% increase in walking speed. A simple linear regression between step length, stride length for given speed were very tightly correlated along a line of best fit $( \mathrm {p}<$.001). The temporal parameters of stride time, stance time and double support time depicted a non-linear exponentially decaying relationship for given walking speed. The research findings indicate that although longitudinal exoskeleton training reduces the temporal parameters, increases in spatial parameters are only marginal.

The goal of this study is to understand the postural adaptations characterized by the whole body center of mass (COM) for individuals with SCI while walking with powered robotic exoskeletons, EksoGTTM and ReWalkTM. COM excursions showed a greater medial-lateral weight shift approach while walking in the EksoGTTM compared to a more forward-lean approach in the ReWalk™, however, postural trunk lean was significantly (p < 0.05) higher in the ReWalkTM. Understanding the effects of exoskeleton designs on posture and sway is crucial towards developing effective and efficient training protocols for rehabilitation and recovery post SCI.

The purpose of this research was to evaluate the therapeutic and training effects of longitudinal robotic exoskeleton training (>50 hours) for an individual with chronic SCI on temporal-spatial and kinematic gait outcomes during independent overground walking without the robot. Gait parameters include stride length, stance/swing times, walking speed, temporal symmetry, sagittal joint range of motion and bilateral weight distribution. Longitudinal exoskeleton training resulted in increased bilateral knee ROM, improved phasic distribution of temporal measures and symmetric weight distribution, which translated to increased overall walking speed to the level of community ambulation (~.4m/s).