Objective measurement of use of the reciprocating gait orthosis (RGO) and the electrically augmented RGO in adult patients with spinal cord lesions

Objective Methods of Monitoring Usage of Orthotic Devices for the Extremities: A Systematic Review

Orthoses are commonly prescribed to relieve symptoms for musculoskeletal and neurological conditions; however, patients stop wearing orthoses as recommended for many reasons. When considering the effectiveness of orthoses, there needs to be an objective way to monitor whether participants wear the orthosis as instructed, because if this is not followed, the orthoses will not work as intended. This review aimed to identify, summarise, and compare objective methods used to measure compliance with orthoses applied to the extremities. Databases (Scopus, Web of Science, Embase, CINAHL, and MEDLINE) were searched for eligible studies. Twenty-three studies were accepted in the final review, including five studies that employed upper limb orthoses, two that employed hip orthoses, and fifteen that employed lower limb orthoses. To measure compliance objectively, studies utilised temperature sensors, pressure sensors, accelerometers, a step counter, or a combination of sensors. All sensor types have their own advantages and disadvantages and should be chosen based on study-specific parameters. Sensor-derived monitoring provides quantitative, objective data that are beneficial in both clinical and research settings. The ideal solution to monitoring compliance would consist of both objective and user-reported aspects that, in combination, would provide an all-encompassing picture of the orthotic treatment prescribed.

Device-Training for Individuals with Thoracic and Lumbar Spinal Cord Injury Using a Powered Exoskeleton for Technically Assisted Mobility: Achievements and User Satisfaction

Objective. Results of a device-training for nonambulatory individuals with thoracic and lumbar spinal cord injury (SCI) using a powered exoskeleton for technically assisted mobility with regard to the achieved level of control of the system after training, user satisfaction, and effects on quality of life (QoL). Methods. Observational single centre study with a 4-week to 5-week intensive inpatient device-training using a powered exoskeleton (ReWalk™). Results. All 7 individuals with SCI who commenced the device-training completed the course of training and achieved basic competences to use the system, that is, the ability to stand up, sit down, keep balance while standing, and walk indoors, at least with a close contact guard. User satisfaction with the system and device-training was documented for several aspects. The quality of life evaluation (SF-12v2™) indicated that the use of the powered exoskeleton can have positive effects on the perception of individuals with SCI regarding what they can achieve physically. Few adverse events were observed: minor skin lesions and irritations were observed; no falls occurred. Conclusions. The device-training for individuals with thoracic and lumbar SCI was effective and safe. All trained individuals achieved technically assisted mobility with the exoskeleton while still needing a close contact guard.

Heart rate and oxygen demand of powered exoskeleton-assisted walking in persons with paraplegia

Historically, persons with paralysis have limited options for overground ambulation. Recently, powered exoskeletons have become available, which are systems that translate the user's body movements to activate motors to move the lower limbs through a predetermined gait pattern. As part of an ongoing clinical study (NCT01454570), eight nonambulatory persons with paraplegia were trained to ambulate with a powered exoskeleton. Measurements of oxygen uptake (VO2) and heart rate (HR) were recorded for 6 min each during each maneuver while sitting, standing, and walking. The average value of VO2 during walking (11.2 +/- 1.7 mL/kg/min) was significantly higher than those for sitting and standing (3.5 +/- 0.4 and 4.3 +/- 0.9 mL/kg/min, respectively; p < 0.001). The HR response during walking was significantly greater than that of either sitting or standing (118 +/- 21vs 70 +/- 10 and 81 +/- 12 beats per minute, respectively: p < 0.001). Persons with paraplegia were able to ambulate efficiently using the powered exoskeleton for overground ambulation, providing potential for functional gain and improved fitness.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov; NCT01454570; "The ReWalk Exoskeletal Walking System for Persons with Paraplegia (VA_ReWalk)"; https://clinicaltrials.gov/ct2/show/NCT01454570.

Electrical Stimulation and Motor Recovery

In recent years, several investigators have successfully regenerated axons in animal spinal cords without locomotor recovery. One explanation is that the animals were not trained to use the regenerated connections. Intensive locomotor training improves walking recovery after spinal cord injury (SCI) in people, and >90% of people with incomplete SCI recover walking with training. Although the optimal timing, duration, intensity, and type of locomotor training are still controversial, many investigators have reported beneficial effects of training on locomotor function. The mechanisms by which training improves recovery are not clear, but an attractive theory is available. In 1949, Donald Hebb proposed a famous rule that has been paraphrased as “neurons that fire together, wire together.” This rule provided a theoretical basis for a widely accepted theory that homosynaptic and heterosynaptic activity facilitate synaptic formation and consolidation. In addition, the lumbar spinal cord has a locomotor center, called the central pattern generator (CPG), which can be activated nonspecifically with electrical stimulation or neurotransmitters to produce walking. The CPG is an obvious target to reconnect after SCI. Stimulating motor cortex, spinal cord, or peripheral nerves can modulate lumbar spinal cord excitability. Motor cortex stimulation causes long-term changes in spinal reflexes and synapses, increases sprouting of the corticospinal tract, and restores skilled forelimb function in rats. Long used to treat chronic pain, motor cortex stimuli modify lumbar spinal network excitability and improve lower extremity motor scores in humans. Similarly, epidural spinal cord stimulation has long been used to treat pain and spasticity. Subthreshold epidural stimulation reduces the threshold for locomotor activity. In 2011, Harkema et al. reported lumbosacral epidural stimulation restores motor control in chronic motor complete patients. Peripheral nerve or functional electrical stimulation (FES) has long been used to activate sacral nerves to treat bladder and pelvic dysfunction and to augment motor function. In theory, FES should facilitate synaptic formation and motor recovery after regenerative therapies. Upcoming clinical trials provide unique opportunities to test the theory.

Hybrid FES-robot cooperative control of ambulatory gait rehabilitation exoskeleton

Robotic and functional electrical stimulation (FES) approaches are used for rehabilitation of walking impairment of spinal cord injured individuals. Although devices are commercially available, there are still issues that remain to be solved. Control of hybrid exoskeletons aims at blending robotic exoskeletons and electrical stimulation to overcome the drawbacks of each approach while preserving their advantages. Hybrid actuation and control have a considerable potential for walking rehabilitation but there is a need of novel control strategies of hybrid systems that adequately manage the balance between FES and robotic controllers. Combination of FES and robotic control is a challenging issue, due to the non-linear behavior of muscle under stimulation and the lack of developments in the field of hybrid control. In this article, a cooperative control strategy of a hybrid exoskeleton is presented. This strategy is designed to overcome the main disadvantages of muscular stimulation: electromechanical delay and change in muscle performance over time, and to balance muscular and robotic actuation during walking.

Experimental results in healthy subjects show the ability of the hybrid FES-robot cooperative control to balance power contribution between exoskeleton and muscle stimulation. The robotic exoskeleton decreases assistance while adequate knee kinematics are guaranteed. A new technique to monitor muscle performance is employed, which allows to estimate muscle fatigue and implement muscle fatigue management strategies. Kinesis is therefore the first ambulatory hybrid exoskeleton that can effectively balance robotic and FES actuation during walking. This represents a new opportunity to implement new rehabilitation interventions to induce locomotor activity in patients with paraplegia.

Acronym list: 10mWT: ten meters walking test; 6MWT: six minutes walking test; FSM: finite-state machine; t-FSM: time-domain FSM; c-FSM: cycle-domain FSM; FES: functional electrical stimulation; HKAFO: hip-knee-ankle-foot orthosis; ILC: iterative error-based learning control; MFE: muscle fatigue estimator; NILC: Normalized stimulation output from ILC controller; PID: Proportional-Integral-derivative Control; PW: Stimulation pulse width; QUEST: Quebec User Evaluation of Satisfaction with assistive Technology; SCI: Spinal cord injury; TTI: torque-time integral; VAS: Visual Analog Scale.

Functional walking ability of paraplegic patients: comparison of functional electrical stimulation versus mechanical orthoses

BACKGROUND

Spinal cord injury (SCI) can cause partial or complete paralysis of the lower extremities, impairing the ability of individuals to stand and walk. Various types of mechanical orthoses, functional electrical stimulation (FES) systems and hybrid orthoses that incorporate FES have been designed to restore the ability of individuals with SCI to stand and walk. Standing and ambulation performance of SCI subjects using these different systems have been previously evaluated using energy consumption analysis, stability analysis and by quantitative gait analysis. Though FES-based systems are technologically more complex than passive mechanical systems, it is not apparent whether user performance is substantially improved with FES and hybrid orthoses compared to purely mechanical orthoses.

METHOD

An electronic search was performed via the Pubmed, Embase and ISI Web of Knowledge data base from 1960 to 2010. The abstracts, titles and full details of each individual study were assessed by the authors. The findings that were indicative of users' performance with the FES systems and hybrid systems were compared with that of mechanical orthoses. Moreover, the effects of using these different systems on physiological health were evaluated.

RESULTS

Twelve original articles and 5 review articles were selected by the author. However, most of the original articles were case studies. The results of previous investigations indicate that user performance with the mechanical orthoses was generally better than that of the hybrid and FES systems based on subject's stability and energy consumption while walking. Moreover, subject reportedly experienced a higher incidence of problems with the use of hybrid orthoses and FES systems compared with mechanical orthoses.

CONCLUSION

FES and hybrid orthoses offer considerable potential for restoring standing and walking abilities in persons with SCI. However, improvements in their designs and operation with subsequent objective evaluations are required to demonstrate that these systems enable users to improve their performance over that currently possible with passive, mechanical orthoses.

A systematic review of the efficacy of gait rehabilitation strategies for spinal cord injury

OBJECTIVE: To systematically review the evidence for the efficacy of different rehabilitation strategies on functional ambulation following spinal cord injury (SCI). METHODS: A keyword literature search of original articles was used to identify published literature evaluating the effectiveness of any treatment or therapy on functional ambulation in people with SCI. The rigor and quality of each study were scored on standardized scales by two independent reviewers. RESULTS: The search yielded 160 articles, of which 119 were excluded for not meeting our inclusion criteria. The remaining 41 articles covered various strategies for improving gait: bodyweight supported treadmill training (BWSTT) (n=12), functional electrical stimulation (FES) (n=7), braces/orthoses (n=10), or a combination of these (n=12). There is strong evidence from randomized controlled trials that functional ambulation outcomes following body-weight supported treadmill training (BWSTT) are comparable to an equivalent intensity of overground gait training in sub-acute SCI. In chronic SCI, evidence from pre-test/post-test studies shows that BWSTT may be effective in improving functional ambulation. Pre-test/post-test or post-test only studies provide evidence that FES may augment functional ambulation in sub-acute/chronic SCI while braces may afford particular benefits to people with complete SCI to stand up and ambulate with assistive devices. CONCLUSIONS: Rehabilitation strategies that facilitate repeated practice of gait offer the greatest benefits to functional ambulation in sub-acute or chronic SCI. Supportive devices may augment functional ambulation particularly in people with incomplete SCI.

Effect of electrical stimulation of hamstrings and l3/4 dermatome on gait in spinal cord injury

Objective.  To determine the effect of electrical stimulation of hamstrings and L3/4 dermatome on the swing phase of gait. Materials and Methods.  Five subjects with incomplete spinal cord injury (SCI) with spasticity were included. Two electrical stimulation methods were investigated, i.e., hamstrings and L3/4 dermatome stimulation. Both interventions were applied during the swing phase of gait. The main outcome measures were step length, maximum hip, and knee flexion during the swing phase of gait. In three subjects changes of spinal inhibition during gait were evaluated using the Hoffman reflex/m (motor)-wave (H/M) ratio at mid swing. Results.  The hip flexion decreased 4.6° (p < 0.05) when the hamstrings were stimulated during the swing phase, whereas the knee flexion was not changed. The step length did not change significantly. One subject showed a decrease of the H/M ratio to a nonpathologic level during hamstrings stimulation. Conclusion.  It was concluded that hamstrings stimulation during the swing phase results in a reduction of the hip flexion in all five SCI subjects. The H/M ratio of the vastus lateralis was normalized using hamstrings stimulation in one of three subjects. Stimulation of the L3/4 dermatome provides no significant changes in gait performance, but in one subject the H/M ratio increased.

Gait impairments in a group of patients with incomplete spinal cord injury and their relevance regarding therapeutic approaches using functional electrical stimulation

The purpose of this study is to determine the most important impairments affecting the gait pattern of the incomplete spinal cord injury (SCI) patient and the potential impact of their treatment. The study consists of two parts. Firstly, a survey amongst 16 professionals was done to find out the impact of the impairments in incomplete-SCI patients. Secondly, gait data from 21 individuals were analyzed to determine the most common impairments. Frequently observed and relevant impairments were: inadequate hip extension (occurrence 76%), limited hip flexion (52%), limited knee flexion (71%), excess of plantar flexion (76%), and impaired foot contact (52%). In conclusion, for gait improvement in incomplete spinal cord injured patients not only ankle movements must be treated, which is done frequently, but also hip extension/flexion and knee flexion are important for gait restoration. The impact on the gait and potential solutions of these impairments are discussed.