Motor and autonomic concomitant health improvements with neuromodulation and exercise (MACHINE) training: a randomised controlled trial in individuals with spinal cord injury.

INTRODUCTION: Motor and autonomic dysfunctions are widespread among people with spinal cord injury (SCI), leading to poor health and reduced quality of life. Exercise interventions, such as locomotor training (LT), can promote sensorimotor and autonomic recovery post SCI. Recently, breakthroughs in SCI research have reported beneficial effects of electrical spinal cord stimulation (SCS) on motor and autonomic functions. Despite literature supporting the independent benefits of transcutaneous SCS (TSCS) and LT, the effect of pairing TSCS with LT is unknown. These therapies are non-invasive, customisable and have the potential to simultaneously benefit both sensorimotor and autonomic functions. The aim of this study is to assess the effects of LT paired with TSCS in people with chronic SCI on outcomes of sensorimotor and autonomic function. METHODS AND ANALYSIS: Twelve eligible participants with chronic (>1 year) motor-complete SCI, at or above the sixth thoracic segment, will be enrolled in this single-blinded, randomised sham-controlled trial. Participants will undergo mapping for optimisation of stimulation parameters and baseline assessments of motor and autonomic functions. Participants will then be randomly assigned to either LT+TSCS or LT+Sham stimulation for 12 weeks, after which postintervention assessments will be performed to determine the effect of TSCS on motor and autonomic functions. The primary outcome of interest is attempted voluntary muscle activation using surface electromyography. The secondary outcomes relate to sensorimotor function, cardiovascular function, pelvic organ function and health-related quality of life. Statistical analysis will be performed using two-way repeated measures Analysis of variance (ANOVAs) or Kruskal-Wallis and Cohen's effect sizes. ETHICS AND DISSEMINATION: This study has been approved after full ethical review by the University of British Columbia's Research Ethics Board. The stimulator used in this trial has received Investigation Testing Authorisation from Health Canada. Trial results will be disseminated through peer-reviewed publications, conference presentations and seminars. TRIAL REGISTRATION NUMBER: NCT04726059.

Effects of non-invasive spinal cord stimulation on lower urinary tract, bowel, and sexual functions in individuals with chronic motor-complete spinal cord injury: Protocol for a pilot clinical trial.

INTRODUCTION: Electrical spinal cord neuromodulation has emerged as a leading intervention for restoring autonomic functions, such as blood pressure, lower urinary tract (LUT), bowel, and sexual functions, following spinal cord injury (SCI). While a few preliminary studies have shown the potential effect of non-invasive transcutaneous spinal cord stimulation (tSCS) on autonomic recovery following SCI, the optimal stimulation parameters, as well as real-time and long-term functional benefits of tSCS are understudied. This trial entitled "Non-invasive Neuromodulation to Treat Bladder, Bowel, and Sexual Dysfunction following Spinal Cord Injury" is a pilot trial to examine the feasibility, dosage effect and safety of tSCS on pelvic organ function for future large-scale randomized controlled trials. METHODS AND ANALYSIS: Forty eligible participants with chronic cervical or upper thoracic motor-complete SCI will undergo stimulation mapping and assessment batteries to determine the real-time effect of tSCS on autonomic functions. Thereafter, participants will be randomly assigned to either moderate or intensive tSCS groups to test the dosage effect of long-term stimulation on autonomic parameters. Participants in each group will receive 60 minutes of tSCS per session either twice (moderate) or five (intensive) times per week, over a period of six weeks. Outcome measures include: (a) changes in bladder capacity through urodynamic studies during real-time and after long-term tSCS, and (b) resting anorectal pressure determined via anorectal manometry during real-time tSCS. We also measure assessments of sexual function, neurological impairments, and health-related quality of life using validated questionnaires and semi-structured interviews. ETHICS AND DISSEMINATION: Ethical approval has been obtained (CREB H20-01163). All primary and secondary outcome data will be submitted to peer-reviewed journals and disseminated among the broader scientific community and stakeholders.

Knowledge, Attitudes, and Practice of Pelvic Floor Muscle Training in People With Spinal Cord Injury: A Cross-Sectional Survey.

Background: There is emerging evidence that pelvic floor muscle training (PFMT) may be useful for treating some urogenital conditions in people with spinal cord injury (SCI). Future clinical investigations would benefit from understanding the extent to which people with SCI are aware of and practicing PFMT, and their attitude toward this therapy. Objective: The goal of this study was to assess the knowledge, attitudes, and practices related to PFMT among people with SCI. Methods: We distributed an internet survey internationally via SCI related organizations for 2 months. We used descriptive statistics to summarize each survey item, and Chi-square and Mann-Whitney U tests to explore the differences in results between sexes and level of motor-function. Results: Complete data from 153 respondents were analyzed. Sixty-two percent of respondents were female and 71% reported having complete paralysis. More than half of respondents reported being aware of PFMT (63%); more females than males reported knowledge of PFMT (p = 0.010). Females (p = 0.052) and people with partial paralysis (p = 0.008) reported a stronger belief that they would benefit from PFMT. Few people with SCI had practiced PFMT (20%), and of those who practiced, most of them had SCI resulting in partial paralysis (p = 0.023). Conclusions: While people with SCI may be aware of and have favorable attitudes toward PFMT, few had practiced PFMT and there were notable differences in attitudes toward PFMT depending on the sex and level of motor function of the respondents.

Characterizing Pelvic Floor Muscle Activity During Walking and Jogging in Continent Adults: A Cross-Sectional Study.

Introduction: The pelvic floor muscles (PFM) are active during motor tasks that increase intra-abdominal pressure, but little is known about how the PFM respond to dynamic activities, such as gait. The purpose of this study was to characterize and compare PFM activity during walking and jogging in continent adults across the entire gait cycle. Methods: 17 able-bodied individuals (8 females) with no history of incontinence participated in this study. We recorded electromyography (EMG) from the abdominal muscles, gluteus maximus (GM), and PFM while participants performed attempted maximum voluntary contractions (aMVC) of all muscles and completed 60-70 strides in four gait conditions: slow walk (1 km/h); regular walk (self-selected comfortable pace); transition walk (self-selected fastest walking pace); jog (same speed as transition walking). We quantified activity throughout the whole gait cycle (%aMVCGC) and during periods of bursting (%aMVCBR) for each participant, and analyzed the timing of PFM bursting periods to explore when the PFM were most active in the gait cycle. We also conducted a phase metric analysis on the PFM and GM burst timings. We performed a Spearman's rank-order correlation to examine the effect of speed on %aMVCGC, %aMVCBR, and phase metric score, and used the Wilcoxon Signed-Rank test to evaluate the effect of gait modality, matched for speed (walking vs. jogging), on these variables. Results: The PFM were active throughout the gait cycle, with bursts typically occurring during single-leg support. The PFM and GM were in phase for 44-69% of the gait cycle, depending on condition. There was a positive correlation between gait speed and both %aMVCGC and %aMVCBR (p < 0.001). Phase metric scores were significantly higher during jogging than transition walking (p = 0.005), but there was no difference between gait modality on %aMVCGC or %aMVCBR (p = 0.059). Where possible we disaggregated data by sex, although were unable to make statistical comparisons due to low sample sizes. Conclusion: The PFM are active during walking and jogging, with greater activity at faster speeds and with bursts in activity around single-leg support. The PFM and GM co-activate during gait, but are not completely in phase with each other.

Accidental boosting in an individual with tetraplegia - considerations for the interpretation of cardiopulmonary exercise testing.

CONTEXT: Autonomic dysreflexia (AD), characterized by a transient increase in systolic blood pressure (BP), is experienced by individuals with spinal cord injury (SCI) and can be purposefully induced ('boosting') to counteract autonomic dysfunction that impairs cardiovascular responses to exercise. Herein, we demonstrate the impact of unintentional boosting observed during cardiopulmonary exercise testing (CPET) in an inactive male with SCI (C5, motor-complete). FINDINGS: On two separate occasions the individual performed a standard arm-crank CPET (1-min stages, 7W increase in resistance) following by a longer CPET (4-min stages, 12W increase in resistance), both to volitional exhaustion. The second CPET was performed to confirm the accuracy of exercise intensity prescription and verify peak exercise parameters. Immediately following the second CPET on the initial visit, the individual reported symptoms of AD, verified as a 58mmHg increase in systolic BP from baseline. Relative to the first CPET, performed only 35 min earlier, there were pronounced differences in peak exercise responses. In comparison to the longer CPET performed on the second visit without a concomitant episode of AD (thereby controlling for the type of CPET protocol administered), peak exercise outcomes were considerably elevated: power output (Δ19W), oxygen uptake (Δ3.61 ml·â€…kg·-1min-1), ventilation (Δ11.4 L ·min-1) and heart rate (Δ9 b·min-1). CONCLUSION/CLINICAL RELEVANCE: This case raises important considerations around the nuances of CPET in this population. In individuals susceptible to BP instability, the physiologically boosted state may explain a significant proportion of the variance in peak aerobic capacity and should be closely monitored before and after clinical CPET.

Effects of motor stimulation of the tibial nerve on corticospinal excitability of abductor hallucis and pelvic floor muscles.

Introduction: Peripheral nerve stimulation can modulate the excitability of corticospinal pathways of muscles in the upper and lower limbs. Further, the pattern of peripheral nerve stimulation (continuous vs. intermittent) may be an important factor determining the modulation of this corticospinal excitability. The pelvic floor muscles (PFM) are crucial for maintaining urinary continence in humans, and share spinal segmental innervation with the tibial nerve. We explored the idea of whether the neuromodulatory effects of tibial nerve stimulation (TibNS) could induce effects on somatic pathways to the PFM. We evaluated the effects of two patterns of stimulation (intermittent vs. continuous) on corticospinal excitability of the PFM compared to its effect on the abductor hallucis (AH) muscle (which is directly innervated by the tibial nerve). We hypothesized that intermittent TibNS would increase, while continuous stimulation would decrease, the excitability of both AH and PFM. Methods: Twenty able-bodied adults (20-33 years of age) enrolled in this study. TibNS was delivered either intermittently (1 ms pulses delivered at 30Hz with an on:off duty cycle of 600:400 ms, for 60 min), or continuously (1 ms pulses delivered at 30Hz for 36 min) just above the motor threshold of the AH. We randomized the order of the stimulation pattern and tested them on separate days. We used surface electromyography (EMG) to record motor-evoked responses (MEP) in the PFM and AH following transcranial magnetic stimulation (TMS). We generated stimulus-response (SR) curves to quantify the changes in peak-to-peak MEP amplitude relative to TMS intensity to assess changes in corticospinal excitability pre- and post-stimulation. Results and Conclusion: We found that TibNS increased corticospinal excitability only to AH, with no effects in PFM. There was no difference in responses to continuous vs. intermittent stimulation. Our results indicate a lack of effect of TibNS on descending somatic pathways to the PFM, but further investigation is required to explore other stimulation parameters and whether neuromodulatory effects may be spinal in origin.

Probing the deployment of peripheral visual attention during obstacle-crossing planning.

Gaze is directed to one location at a time, making peripheral visual input important for planning how to negotiate different terrain during walking. Whether and how the brain attends to this input is unclear. We developed a novel paradigm to probe the deployment of sustained covert visual attention by testing orientation discrimination of a Gabor patch at stepping and non-stepping locations during obstacle-crossing planning. Compared to remaining stationary, obstacle-crossing planning decreased visual performance (percent correct) and sensitivity (d') at only the first of two stepping locations. Given the timing of the first and second steps before obstacle crossing relative to the Gabor patch presentation, the results suggest the brain uses peripheral vision to plan one step at a time during obstacle crossing, in contrast to how it uses central vision to plan two or more steps in advance. We propose that this protocol, along with multiple possible variations, presents a novel behavioral approach to identify the role of covert visual attention during obstacle-crossing planning and other goal-directed walking tasks.

Trunk muscle activity and kinematics during boxing and battle rope exercise in people with motor-complete spinal cord injury.

CONTEXT: Recovery of seated balance is a rehabilitation priority for people with motor-complete spinal cord injury (mcSCI). Previous research has demonstrated that people with mcSCI can voluntarily engage their trunk muscles during different exercise programs that have the potential to improve seated balance control. Boxing and battle rope exercises could offer another opportunity to improve seated balance for people with mcSCI, but it is unknown if this type of exercise engages trunk musculature and challenges seated balance. OBJECTIVE: To describe the movement patterns of people with mcSCI compared to controls by characterizing the muscle activation patterns and kinematics of the trunk and upper-body during boxing and battle rope exercise. DESIGN: Cross-sectional study. PARTICIPANTS: 4 males with mcSCI between C7-T9, and 4 able-bodied controls. METHODS: Participants performed different boxing and battle rope exercises while kinematics and electromyography (EMG) from the trunk and arms were recorded. OUTCOME MEASURES: Trunk EMG amplitude, trunk and arm joint angles, and trunk curvature. RESULTS: Boxing and battle ropes elicited higher relative EMG activity in people with mcSCI compared to controls (P < 0.001). Participants with mcSCI had similar upper-limb kinematics during the exercises to controls, but demonstrated reduced trunk rotation and increased trunk curvature. CONCLUSIONS: These findings suggest that boxing and battle rope can elicit trunk activity in people with mcSCI, though they may adopt increased trunk curvatures. Future research should explore if such exercise programs may improve seated balance in people with mcSCI.

Exoskeleton gait training to improve lower urinary tract function in people with motor-complete spinal cord injury: A randomized pilot trial.

OBJECTIVE: The primary aim of this study was to determine the feasibility of delivering an exoskeleton-assisted walking intervention targeting lower urinary tract function in people with motor-complete spinal cord injury. Secondary aims were to determine if exoskeleton walking activates the pelvic floor muscles, and compare 2 exoskeleton programmes regarding lower urinary tract function. DESIGN: Randomized pilot trial. SUBJECTS: Adults with motor-complete spinal cord injury at or above T10. METHODS: Participants were randomized to receive Ekso or Lokomat training. Feasibility outcomes included recruitment rate, adherence, and adverse events. Pelvic floor muscle electromyography was recorded during walking. Urodynamic studies, 3-day bladder diary, and Qualiveen-30 were administered pre- and post-training. RESULTS: Twelve people were screened and 6 people enrolled in the study. Two subjects withdrew from unrelated reasons. There was one adverse event. Pelvic floor muscle activity was greater in the Ekso group. Lower urinary tract function did not clearly change in either group. CONCLUSION: This pilot study demonstrates the feasibility of delivering an exoskeleton training programme targeting lower urinary tract function. Ekso-walking elicits pelvic floor muscle activity, but it remains unclear how locomotor training impacts lower urinary tract function.

Noninvasive Neuroprosthesis Promotes Cardiovascular Recovery After Spinal Cord Injury.

Spinal cord injury (SCI) leads to severe impairment in cardiovascular control, commonly manifested as a rapid, uncontrolled rise in blood pressure triggered by peripheral stimuli-a condition called autonomic dysreflexia. The objective was to demonstrate the translational potential of noninvasive transcutaneous stimulation (TCS) in mitigating autonomic dysreflexia following SCI, using pre-clinical evidence and a clinical case report. In rats with SCI, we show that TCS not only prevents the instigation of autonomic dysreflexia, but also mitigates its severity when delivered during an already-triggered episode. Furthermore, when TCS was delivered as a multisession therapy for 6 weeks post-SCI, the severity of autonomic dysreflexia was significantly reduced when tested in the absence of concurrent TCS. This treatment effect persisted for at least 1 week after the end of therapy. More importantly, we demonstrate the clinical applicability of TCS in treatment of autonomic dysreflexia in an individual with cervical, motor-complete, chronic SCI. We anticipate that TCS will offer significant therapeutic advantages, such as obviating the need for surgery resulting in reduced risk and medical expenses. Furthermore, this study provides a framework for testing the potential of TCS in improving recovery of other autonomic functions such lower urinary tract, bowel, and sexual dysfunction following SCI.

Effects of Exercise-Based Interventions on Urogenital Outcomes in Persons with Spinal Cord Injury: A Systematic Review and Meta-Analysis.

In this systematic review, objectives were to investigate dropout rates, adverse events, and effects of exercise-based therapies on urogenital function and quality of life (QoL) in persons with spinal cord injury (SCI). Database searches were conducted on MEDLINE, EMBASE, and CINAHL for studies examining any form of exercise intervention on urogenital function and/or QoL in adults with SCI. Quality of publications was evaluated using the Joanna Briggs Institute critical evaluation tools. When possible, Hedges' g was calculated for overall effect sizes. Subgroup analyses were conducted on sex and injury severity. Ten studies (228 participants) were included in this review. Three studies examined pelvic floor muscle training, and seven studies examined locomotor training. Overall quality of evidence was low because of small sample sizes and non-randomized designs in most studies. Dropout rates ranged from 12% to 25%, and adverse events were reported only in some studies investigating locomotor training. For lower urinary tract (LUT) outcomes, urodynamic findings were mixed despite moderately positive changes in maximum bladder capacity (g = 0.50) and bladder compliance (g = 0.37). Fairly consistent, but small, improvements were observed in LUT symptoms, primarily bladder awareness and incontinence. LUT QoL improved in most cases. Fewer data were available for sexual outcomes, and only minor improvements were reported. Subgroup analyses, based on sex and severity of injury, were inconclusive. There is some indication for the potential benefit of exercise on urogenital outcomes in persons with SCI, but there is insufficient evidence given the number of studies and heterogeneity of outcome measures.

Residual Innervation of the Pelvic Floor Muscles in People with Motor-Complete Spinal Cord Injury.

Individuals classified clinically as having a motor-complete spinal cord injury (mcSCI) should lack voluntary motor function below their injury level. Neurophysiological assessments using electromyography (EMG) and transcranial magnetic stimulation (TMS), however, have demonstrated that persons with mcSCI retain limited cortical descending innervation and voluntary activation of muscles below their level of injury, including muscles of the trunk and lower limb. We explored the possibility of whether there is also preserved innervation of the pelvic floor muscles (PFM) in persons with mcSCI. The PFM are controlled by widespread cortical and subcortical areas and typically coactivated with trunk and gluteal muscles to maintain continence and regulate intra-abdominal pressure. Nine mcSCI and eight control subjects participated in this cross-sectional study. Surface EMG was used to record activity in the PFM. Data were recorded while participants attempted various maneuvers of the trunk and pelvis. We also applied TMS at incrementing levels of intensity over the primary motor cortex area to record motor evoked potentials (MEPs) in the PFM. When performing the maneuvers, activation of the PFM was possible in all controls and the majority of SCI participants. However, the PFM were only activated in the SCI participants during maneuvers that engaged other trunk muscles, however. MEP responses in the PFM were also elicited in all controls and SCI participants, but MEP response characteristics were significantly altered in the SCI group. Our results suggest that persons with mcSCI retain some residual innervation of the PFM after injury, possibly via indirect cortical descending pathways.

Quantifying muscle coactivation in individuals with incomplete spinal cord injury using wavelets.

BACKGROUND: Individuals with incomplete spinal cord injury often have decreased gait function and coactivation of antagonistic muscle pairs. Common ways of quantifying coactivation using electromyographic signals do not consider frequency information in the signal. As electromyographic signals from different motor unit types have different frequency components and muscle fiber type can change in individuals with spinal cord injury, it may be beneficial to consider frequency components. The aims were to demonstrate the utility of using a method which considers temporal and frequency components of the electromyographical signal to quantify coactivation in lower extremity muscles in individuals with incomplete spinal cord injury through 1) comparison with able-bodied individuals and 2) comparison before and after body weight supported treadmill training. METHODS: Frequency decomposition techniques were applied to electromyographical signals to consider the temporal and frequency components of the electromyographical signals to quantify coactivation over a range of frequencies. RESULTS: Our main findings show that correlation coefficients between total EMG intensities of rectus femoris-biceps femoris and medial gastrocnemius-tibialis anterior were significantly different between able-bodied individuals and those with incomplete spinal cord injury (p = 0006, p = 0.01). The correlation spectra of medial gastrocnemius-tibialis anterior of the spinal cord injury group were substantially different than those the able-bodied group, while the EMG normalcy score was significantly different (p = 0.002). We also found that there was a change in coactivation of ankle muscles after body weight supported treadmill training. INTERPRETATION: Our findings indicate that there may be frequency specific differences in muscle coactivation between able-bodied individuals and those with incomplete spinal cord injury. Changes in coactivation were also observed before and after body weight supported treadmill training. These differences may reflect the changes in recruitment patterns of different motor unit types.

Arm crank ergometer "spin" training improves seated balance and aerobic capacity in people with spinal cord injury.

BACKGROUND: There is some evidence that upper-body training modalities can improve not only aerobic capacity but also seated balance in people with spinal cord injury (SCI), even in those classified with motor-complete paralysis above T6. Here, we evaluated the effect of arm crank ergometry (ACE) "spin" training on trunk muscle recruitment and its effects on seated balance and aerobic capacity. METHODS: Eight individuals with high-level complete and 6 with either a low-level complete or a motor-incomplete SCI participated in this study. Participants completed 5 weeks of a group ACE "spin" training protocol which featured modulations in cadence and resistance as well as back-supported and unsupported bouts. Surface electromyography was used to confirm trunk muscle recruitment during unsupported ACE. Changes in aerobic capacity (peak oxygen consumption) and seated balance control (center of pressure parameters) were assessed at pre- and post-intervention. RESULTS: Unsupported ACE was effective for eliciting trunk muscle activity (P < .05). Following training, peak oxygen consumption significantly improved by an average of 16% (P = .005). Static sitting balance significantly improved from pre- to post-intervention, but only when tested with eyes closed as measured by a reduction in area (P = .047) and velocity of center of pressure (P = .013). No significant changes were observed in static sitting balance with eyes open or in dynamic sitting balance. CONCLUSION: Group ACE "spin" classes may benefit not only aerobic fitness but also static seated balance control in people with SCI.

The sensorimotor effects of a lower limb proprioception training intervention in individuals with a spinal cord injury.

Proprioception is critical for movement control. After a spinal cord injury (SCI), individuals not only experience paralysis but may also experience proprioceptive deficits, further confounding motor recovery. The objective of this study was to test the effects of a robotic-based proprioception training protocol on lower limb proprioceptive sense in people with incomplete SCI. A secondary objective was to assess whether the effects of training transferred to a precision stepping task in people with motor-incomplete SCI. Participants with chronic incomplete SCI and able-bodied controls underwent a 2-day proprioceptive training protocol using the Lokomat robotic exoskeleton. The training involved positioning the test leg to various positions and participants were asked to report whether they felt their heel position (end-point position) was higher or lower compared with a reference position. Feedback was provided after each trial to help participants learn strategies that could help them discern different positions of their foot. Changes in end-point position as well as knee joint position sense were assessed pre- and posttraining. We also assessed the effects of proprioception training on the performance of a precision stepping task in people with motor-incomplete SCI. Following training, there were significant improvements in end-point and knee joint position sense in both groups. The magnitude of improvement was related to pretraining (baseline) proprioceptive sense, indicating that those who initially had better lower limb position sense showed greater changes. Participants also showed improvements in performance of a precision stepping task.NEW & NOTEWORTHY We show that it is possible to alter proprioceptive sense in people with incomplete SCI using a passive proprioception training protocol combined with feedback. Improvements in proprioceptive sense transferred from end-point to joint position sense and also to an untrained precision stepping task.

Improvements in skilled walking associated with kinematic adaptations in people with spinal cord injury.

INTRODUCTION: Individuals with motor-incomplete SCI (m-iSCI) remain limited community ambulators, partly because they have difficulty with the skilled walking requirements of everyday life that require adaptations in inter-joint coordination and range of motion of the lower limbs. Following locomotor training, individuals with SCI show improvements in skilled walking and walking speed, however there is limited understanding of how adaptations in lower limb kinematics following training contribute to improvements in walking. OBJECTIVE: To determine the relationship between changes in lower limb kinematics (range of motion and inter-joint coordination) and improvements in walking function (walking speed and skilled walking) following locomotor training. METHODS: Lower limb kinematics were recorded from 8 individuals with chronic m-iSCI during treadmill walking before and after a 3-month locomotor training program. Data were also collected from 5 able-bodied individuals to provide normative values. In individuals with SCI, muscle strength was used to define the stronger and weaker limb. Motion analysis was used to determine, hip, knee and ankle angles. Joint angle-angle plots (cyclograms) were used to quantify inter-joint coordination. Shape differences between pre-and post-training cyclograms were used to assess the changes in coordination and their relation to improvements in walking function. Walking function was assessed using the 10MWT for walking speed and the SCI-FAP for skilled walking. Comparing pre- and post-training cyclograms to the able-bodied pattern was used to understand the extent to which changes in coordination involved the recovery of normative motor patterns. RESULTS: Following training, improvements in skilled walking were significantly related to changes in hip-ankle coordination (ρ = - .833, p = 0.010) and knee range of motion (ρ = .833, p = 0.010) of the weaker limb. Inter-joint coordination tended to revert towards normative patterns, but not completely. No relationships were observed with walking speed. CONCLUSION: Larger changes in hip-ankle coordination and a decrease in knee range of motion in the weaker limb during treadmill walking were related to improvements in skilled walking following locomotor training in individuals with SCI. The changes in coordination seem to reflect some restoration of normative patterns and the adoption of compensatory strategies, depending on the participant.

Acquisition of a precision walking skill and the impact of proprioceptive deficits in people with motor-incomplete spinal cord injury.

Many people with motor-incomplete spinal cord injury (m-iSCI) experience difficulty navigating obstacles, such as curbs and stairs. The ability to relearn walking skills may be limited by proprioceptive deficits. The purpose of this study was to determine the capacity of participants to acquire a precision walking skill, and to evaluate the influence of proprioceptive deficits on the skill acquisition in individuals with m-iSCI. Sixteen individuals with m-iSCI and eight controls performed a precision walking task that required matching their foot height to a target during the swing phase. Proprioceptive deficits were quantified at the hip and knee for joint position and movement detection sense. Participants completed 600 steps of training with visual feedback. Pretraining and posttraining tests were conducted without visual feedback, along with a transfer test with an ankle weight. Posttraining and transfer tests were repeated 1 day later. Participants returned to the laboratory 1 wk later to repeat the training. Performance was calculated as the vertical distance between the target and actual foot height for each step. The posttraining and transfer performances were similar between groups. However, participants with m-iSCI had a slower rate of acquisition to achieve a similar performance level compared with controls. Acquisition rate and posttraining performance of the precision walking task were related to lower limb joint position sense among SCI participants. Although they can achieve a similar level of performance in a precision walking task, proprioceptive deficits impair the rate of learning among individuals with m-iSCI compared with able-bodied controls. NEW & NOTEWORTHY People with motor-incomplete spinal cord injuries are able to achieve the same level of performance accuracy on a precision walking task as able-bodied controls; however, the rate of learning is slower, indicating that more practice is required to stabilize performance. Our findings also show a relationship between impaired sensory function and reduced accuracy when performing a precision walking task after spinal cord injury.

Overground walking with a robotic exoskeleton elicits trunk muscle activity in people with high-thoracic motor-complete spinal cord injury.

BACKGROUND: The trunk muscles are critical for postural control. Recent neurophysiological studies have revealed sparing of trunk muscle function in individuals with spinal cord injury (SCI) classified with thoracic or cervical motor-complete injuries. These findings raise the possibility for recruiting and retraining this spared trunk function through rehabilitation. Robotic gait training devices may provide a means to promote trunk muscle activation. Thus, the objective of this study was to characterize and compare the activation of the trunk muscles during walking with two robotic gait training devices (Ekso and Lokomat) in people with high thoracic motor-complete SCI. METHODS: Participants with chronic motor-complete paraplegia performed 3 speed-matched walking conditions: Lokomat-assisted walking, Ekso-assisted walking overground, and Ekso-assisted walking on a treadmill. Surface electromyography (EMG) signals were recorded bilaterally from the rectus abdominis (RA), external oblique (EO), and erector spinae (ES) muscles. RESULTS: Greater recruitment of trunk muscle EMG was elicited with Ekso-assisted walking compared to the Lokomat. Similar levels of trunk EMG activation were observed between Ekso overground and Ekso on the treadmill, indicating that differences between Ekso and Lokomat could not be attributed to the use of a hand-held gait aid. The level of trunk EMG activation during Lokomat walking was not different than that recorded during quiescent supine lying. CONCLUSIONS: Ekso-assisted walking elicits greater activation of trunk muscles compared to Lokomat-assisted walking, even after controlling for the use of hand-held assistive devices. The requirement of the Ekso for lateral weight-shifting in order to activate each step could lead to better postural muscle activation.