The orthotic effect of functional electrical stimulation on the improvement of walking in stroke patients with a dropped foot: a systematic review

A Propulsion Neuroprosthesis Improves Overground Walking in Community-Dwelling Individuals After Stroke

Functional electrical stimulation (FES) is a common neuromotor intervention whereby electrically evoked dorsiflexor muscle contractions assist foot clearance during walking. Plantarflexor neurostimulation has recently emerged to assist and retrain gait propulsion; however, safe and effective coordination of dorsiflexor and plantarflexor neurostimulation during overground walking has been elusive, restricting propulsion neuroprostheses to harnessed treadmill walking. We present an overground propulsion neuroprosthesis that adaptively coordinates, on a step-by-step basis, neurostimulation to the dorsiflexors and plantarflexors. In 10 individuals post-stroke, we evaluate the immediate effects of plantarflexor neurostimulation delivered with different onset timings, and retention to unassisted walking (NCT06459401). Preferred onset timing differed across individuals. Individualized tuning resulted in a significant 10% increase in paretic propulsion peak (Δ: 1.41 ± 1.52%BW) and an 8% increase in paretic plantarflexor power (Δ: 0.27 ± 0.23 W/kg), compared to unassisted walking. Post-session unassisted walking speed, paretic propulsion peak, and propulsion symmetry all significantly improved by 9% (0.14 ± 0.09 m/s), 28% (2.24 ± 3.00%BW), and 12% (4.5 ± 6.0%), respectively, compared to pre-session measurements. Here we show that an overground propulsion neuroprosthesis can improve overground walking speed and propulsion symmetry in the chronic phase of stroke recovery. Future studies should include a control group to examine the efficacy of gait training augmented by the propulsion neuroprosthesis compared to gait training alone.

Functional electrical stimulation to enhance reactive balance among people with hemiparetic stroke

BACKGROUND

Individuals with stroke demonstrate a twofold higher fall incidence compared to healthy counterparts, potentially associated with deficits in reactive balance control, which is crucial for regaining balance from unpredictable perturbations to the body. Moreover, people with higher stroke-related motor impairment exhibit greater falls and cannot recover balance during higher perturbation intensities. Thus, they might need supplemental agents for fall prevention or even to be included in a perturbation-based protocol. Functional electrical stimulation is a widely used clinical modality for improving gait performance; however, it remains unknown whether it can enhance or interfere with reactive balance control.

METHODS

We recruited twelve ambulatory participants with hemiparetic stroke (61.48 ± 6.77 years) and moderate-to-high motor impairment (Chedoke-McMaster Stroke Leg Assessment ≤ 4/7). Each participant experienced 4 unpredicted paretic gait-slips, with and without functional electrical stimulation (provided 50-500 ms after perturbation) in random order. The paretic quadriceps muscle group was chosen to receive electrical stimulation, considering the role of support limb knee extensors for preventing limb-collapse. Outcomes including primary (laboratory falls), secondary (reactive stability, vertical limb support) and tertiary (compensatory step length, step initiation, execution time) measures were compared between the two conditions.

RESULTS

Participants demonstrated fewer falls, higher reactive stability, and higher vertical limb support (p < 0.05) following gait-slips with functional electrical stimulation compared to those without. This was accompanied by reduced step initiation time and a longer compensatory step (p < 0.05).

CONCLUSION

The application of functional electrical stimulation to paretic quadriceps following gait-slips reduced laboratory fall incidence with enhanced reactive balance outcomes among people with higher stroke-related motor impairment. Our results lay the preliminary groundwork for understanding the instantaneous neuromodulatory effect of functional electrical stimulation in preventing gait-slip falls, future studies could test its therapeutic effect on reactive balance. Clinical registry number: NCT04957355.

Is functional electrical stimulation effective in improving walking in adults with lower limb impairment due to an upper motor neuron lesion? An umbrella review

PURPOSE

To conduct an umbrella review of systematic reviews on functional electrical stimulation (FES) to improve walking in adults with an upper motor neuron lesion.

METHODS

Five electronic databases were searched, focusing on the effect of FES on walking. The methodological quality of reviews was evaluated using AMSTAR2 and certainty of evidence was established through the GRADE approach.

RESULTS

The methodological quality of the 24 eligible reviews (stroke, n = 16; spinal cord injury (SCI), n = 5; multiple sclerosis (MS); n = 2; mixed population, n = 1) ranged from critically low to high. Stroke reviews concluded that FES improved walking speed through an orthotic (immediate) effect and had a therapeutic benefit (i.e., over time) compared to usual care (low certainty evidence). There was low-to-moderate certainty evidence that FES was no better or worse than an Ankle Foot Orthosis regarding walking speed post 6 months. MS reviews concluded that FES had an orthotic but no therapeutic effect on walking. SCI reviews concluded that FES with or without treadmill training improved speed but combined with an orthosis was no better than orthosis alone. FES may improve quality of life and reduce falls in MS and stroke populations.

CONCLUSION

FES has orthotic and therapeutic benefits. Certainty of evidence was low-to-moderate, mostly due to high risk of bias, low sample sizes, and wide variation in outcome measures. Future trials must be of higher quality, use agreed outcome measures, including measures other than walking speed, and examine the effects of FES for adults with cerebral palsy, traumatic and acquired brain injury, and Parkinson's disease.

Effects of ankle-foot orthoses on step activities in the community: a systematic review

PURPOSE

To determine the effects of ankle-foot orthoses (AFO) on step-based physical activities in individuals with neurological, orthopaedic, or cardiovascular disorders.

METHODS

Electronic searches of databases such as Scopus, PubMed, Web of Science, Embase, ProQuest, Cochrane Library, and EBSCO were conducted. Two evaluators independently searched with keywords focusing on step-based physical activities, and either articulated or non-articulated AFO. Study quality was assessed using a modified Downs and Black quality scale.

RESULTS

Eleven studies that met the inclusion criteria were selected, including four being classified as good, four as fair, and three as poor in quality. The majority of these trials found no significant effects of AFO on step activities. Only a few studies reported improvements in step counts and active times in step activity with a limited to moderate level of evidence. Subjective evaluations such as user satisfaction, and physical functionality during step activity, on the other hand, showed substantial changes with the use of AFO interventions, although there was no evidence of improvement in the quality of life.

CONCLUSIONS

Although the AFO did not seem to have a substantial effect on step activity, it appeared to play a vital role in improving the patient satisfaction level of step activity.IMPLICATIONS FOR REHABILITATIONAnkle-foot orthoses (AFO) may not significantly affect the step activity of individuals with impaired ankle-foot complex.AFO may enhance patient-reported satisfaction, physical functioning, participation, and fatigue level during step activity.The patient's perception that the AFO is beneficial is in contrast to objective data showing no significant increase in real-world activity.

Boosting brain-computer interfaces with functional electrical stimulation: potential applications in people with locked-in syndrome

Individuals with a locked-in state live with severe whole-body paralysis that limits their ability to communicate with family and loved ones. Recent advances in brain-computer interface (BCI) technology have presented a potential alternative for these people to communicate by detecting neural activity associated with attempted hand or speech movements and translating the decoded intended movements to a control signal for a computer. A technique that could potentially enrich the communication capacity of BCIs is functional electrical stimulation (FES) of paralyzed limbs and face to restore body and facial movements of paralyzed individuals, allowing to add body language and facial expression to communication BCI utterances. Here, we review the current state of the art of existing BCI and FES work in people with paralysis of body and face and propose that a combined BCI-FES approach, which has already proved successful in several applications in stroke and spinal cord injury, can provide a novel promising mode of communication for locked-in individuals.

tDCS does not add effect to foot drop stimulator and gait training in improving clinical parameters and neuroplasticity biomarkers in chronic post-stroke: randomized controlled trial

BACKGROUND

Transcranial direct current stimulation (tDCS) and foot drop stimulators (FDS) are widely used for stroke rehabilitation. However, no study has investigated if tDCS could boost the effects of FDS and gait training in improving clinical parameters and neuroplasticity biomarkers of chronic post-stroke subjects.

OBJECTIVE

To investigate the effects of combining tDCS and FDS on motor impairment, functional mobility, and brain-derived neurotrophic factor (BDNF) serum levels. Also, to evaluate the effects of this protocol on the insulin-like growth factor-1 (IGF-1), insulin growth factor-binding proteins-3 (IGFBP-3), interleukin (IL) 6 and 10, and tumor necrosis factor-α (TNF-α) levels.

METHODS

Thirty-two chronic post-stroke individuals were randomized to tDCS plus FDS or sham tDCS plus FDS groups. Both groups underwent ten gait training sessions for two weeks using a FDS device and real or sham tDCS. Blood samples and clinical data were acquired before and after the intervention. Motor impairment was assessed by the Fugl-Meyer Assessment and functional mobility using the Timed up and Go test.

RESULTS

Both groups improved the motor impairment and functional mobility and increased the BDNF levels. Both groups also increased the IL-10 and decreased the cortisol, IL-6, and TNF-α levels. No difference was observed between groups.

CONCLUSION

tDCS did not add effect to FDS and gait training in improving clinical parameters and neuroplasticity biomarkers in chronic post-stroke individuals. Only FDS and gait training might be enough for people with chronic stroke to modify some clinical parameters and neuroplasticity biomarkers.

CHECGAIT: A Functional Electrical Stimulation Clinical Pathway to Reduce Foot Drop during Walking in Adult Patients with Upper Motor Neuron Lesions

Foot drop during the swing phase of gait and at initial foot contact is a current kinematic abnormality that can occur following an upper motor neuron (UMN) lesion. Functional electrical stimulation (FES) of the common peroneal nerve through an assistive device is often used in neuro-rehabilitation to help patients regain mobility. Although there are FES-specific guideline recommendations, it remains a challenge for clinicians to appropriately select patients eligible for the daily use of FES devices, as very few health insurance systems cover its cost in Europe. In Luxembourg, since 2018, successfully completing an FES clinical pathway called CHECGAIT is a prerequisite to receiving financial coverage for FES devices from the national health fund (Caisse Nationale de Santé-CNS). This study describes the structure and steps of CHECGAIT and reports our experience with a cohort of 100 patients enrolled over a three-year period. The clinical and gait outcomes of all patients were retrospectively quantified, and a specific analysis was performed to highlight differences between patients with and without an FES device prescription at the end of a CHECGAIT. Several significant gait differences were found between these groups. These results and CHECGAIT may help clinicians to better select patients who can most benefit from this technology in their daily lives. In addition, CHECGAIT could provide significant savings to public health systems by avoiding unnecessary deliveries of FES devices.

Evaluating the validity of a functional electrical stimulation clinical decision making tool: A qualitative study

INTRODUCTION

Following central nervous system damage, the recovery of motor function is a priority. For some neurological populations, functional electrical stimulation (FES) is recommended in best practice guidelines for neurorehabilitation. However, limited resources exist to guide FES application, despite clinicians reporting that a lack of FES knowledge prevents use in clinical practice. The FES Clinical Decision Making Tool was developed to assist clinicians with FES application and translation into clinical practice. The purpose of this study was to evaluate the content validity of the Tool from the perspectives of Canadian physical and occupational therapists using FES in neurorehabilitation.

METHODS

Thirteen participants (twelve women, one man), aged 40.5 ± 10.3 years, participated in individual semi-structured interviews to explore their clinical decision making experiences when applying FES and to evaluate the content validity (i.e., appropriateness, comprehensibility, and comprehensiveness) of the Tool. Interviews were analyzed using a qualitative conventional content analysis following the DEPICT model.

RESULTS

Three themes were identified. 1) Clinician context influences FES usage. Participants' experiences with FES use varied and application was influenced by treatment goals. 2) Parameter selection in clinical practice. Participants identified decision-making strategies and the challenges of parameter selection. 3) With modifications, the Tool is a valid resource to inform FES applications. Participants discussed its strengths, limitations, and suggested changes. While the Tool is useful, a more extensive resource (e.g., appendix) for the Tool is warranted.

DISCUSSION

A revised Tool was created to improve its comprehensiveness and comprehensibility. Thus, the Tool is a valid resource for applying FES in neurorehabilitation.

Changes in corticospinal and spinal reflex excitability through functional electrical stimulation with and without observation and imagination of walking

Functional electrical stimulation (FES), a method for inducing muscle contraction, has been successfully used in gait rehabilitation for patients with deficits after neurological disorders and several clinical studies have found that it can improve gait function after stroke and spinal cord injury. However, FES gait training is not suitable for patients with walking difficulty, such as those with severe motor paralysis of the lower limbs. We have previously shown that action observation combined with motor imagery (AO + MI) of walking induces walking-related cortical activity. Therefore, we combined FES, which alternately generates dorsiflexion and plantar flexion, with AO + MI as an alternative to gait training. The present study investigates the transient effects of 20-min of FES simultaneously with and without AO + MI of walking on corticospinal and spinal reflex excitability in able-bodied participants. We measured motor evoked potentials and Hoffmann-reflexes to assess corticospinal and spinal reflex excitability at rest before and after the 20-min FES with and without the AO + MI. Our results show that FES without AO + MI did not change excitability (p &gt; 0.05), while FES with AO + MI facilitated corticospinal excitability (p &lt; 0.05). This facilitation likely occurred due to the synchronization of sensory inputs from FES and cortical activity during AO + MI. Facilitation was observed only in the dorsiflexor but not the plantar flexor muscle (p &lt; 0.05), suggesting muscle specificity of the facilitation. These results demonstrate the effectiveness of combining FES with AO + MI and pave the way for novel neurorehabilitation strategies for patients with neurological gait deficits.

Is Foot Drop an Underreported Sequela of Extracorporeal Membrane Oxygenation?

Foot drop in the absence of limb ischemia is a chronic complication in peripheral venoarterial extracorporeal membrane oxygenation (V-A ECMO) survivors; however, there is little published regarding the incidence and functional outcomes of this condition. Common peroneal nerve is the most common cause of foot drop, a condition that leads to significant debility and requires extensive physical therapy and rehabilitation, thereby affecting the patient's quality of life. We completed a retrospective review of 153 patients who received femoral cannulation for V-A ECMO support for greater than 1 hour. The incidence of foot drop in our V-A ECMO population was 7.8% (12/153). Importantly, only two patients with foot drop were discharged home. The majority (10/12) of patients with foot drop required in-patient rehabilitation; five patients were nonambulatory, and five patients required an ankle foot orthosis assistive device. This study identifies foot drop as a relevant complication in peripherally cannulated V-A ECMO survivors and provides an initial incidence rate. By raising awareness of this complication in the V-A ECMO population, an early diagnosis is possible, which can enable appropriate rehabilitation. Prospective trials are needed to identify possible risk factors of foot drop and methods to reduce this complication of V-A ECMO.

Investigating the underlying biomechanical mechanisms leading to falls in long-term ankle-foot orthosis and functional electrical stimulator users with chronic stroke

BACKGROUND

Ankle-foot-orthoses (AFOs) and functional electrical stimulators (FES) are commonly prescribed to treat foot-drop in individuals with stroke. Despite well-established positive impacts of AFO and FES devices on balance and gait, AFO and FES-users still fall at a high rate.

OBJECTIVE

The objective of this study was to investigate 1) the underlying biomechanical mechanisms leading to a fall in long-term AFO and FES-users with chronic stroke and 2) the impacts of AFOs and FES devices on fall outcomes and compensatory stepping response of long-term users with chronic stroke.

METHODS

Fall outcomes as well as kinematics and kinetics of compensatory stepping response of 42 individuals with chronic stroke (14 AFO-users, 10 FES-users, 18 Non-users) were evaluated during trip-like treadmill perturbations. AFO and FES-users were evaluated with and without their device.

RESULTS

Chronic AFO and FES-users fell 2.50 and 2.77 times more than Non-users. The most robust differences between AFO/FES-users and Non-users were 1) Reduced capacity to stabilize the trunk through reduction in forward whole-body angular momentum and 2) diminished capability to prepare and generate a second step using the paretic leg. Provocatively, the removal of AFO and FES devices did not decease/increase falls or change kinematics.

SIGNIFICANCE

It is well-established that AFOs/FES devices have a positive impact on static balance and decrease community falls by increasing toe clearance thus preventing trips/stumbles. However, our results suggest that once a trip occurs, these devices do not adequately assist recovery of balance. Specifically, current AFO and FES devices do not assist with second step generation or trunk control. Future studies should explore new devices or training paradigms that target enhancing trunk control and paretic compensatory stepping to decrease falls in this population.

Ultrasound Echogenicity as an Indicator of Muscle Fatigue during Functional Electrical Stimulation

Functional electrical stimulation (FES) is a potential neurorehabilitative intervention to enable functional movements in persons with neurological conditions that cause mobility impairments. However, the quick onset of muscle fatigue during FES is a significant challenge for sustaining the desired functional movements for more extended periods. Therefore, a considerable interest still exists in the development of sensing techniques that reliably measure FES-induced muscle fatigue. This study proposes to use ultrasound (US) imaging-derived echogenicity signal as an indicator of FES-induced muscle fatigue. We hypothesized that the US-derived echogenicity signal is sensitive to FES-induced muscle fatigue under isometric and dynamic muscle contraction conditions. Eight non-disabled participants participated in the experiments, where FES electrodes were applied on their tibialis anterior (TA) muscles. During a fatigue protocol under either isometric and dynamic ankle dorsiflexion conditions, we synchronously collected the isometric dorsiflexion torque or dynamic dorsiflexion angle on the ankle joint, US echogenicity signals from TA muscle, and the applied stimulation intensity. The experimental results showed an exponential reduction in the US echogenicity relative change (ERC) as the fatigue progressed under the isometric (R2=0.891±0.081) and dynamic (R2=0.858±0.065) conditions. The experimental results also implied a strong linear relationship between US ERC and TA muscle fatigue benchmark (dorsiflexion torque or angle amplitude), with R2 values of 0.840±0.054 and 0.794±0.065 under isometric and dynamic conditions, respectively. The findings in this study indicate that the US echogenicity signal is a computationally efficient signal that strongly represents FES-induced muscle fatigue. Its potential real-time implementation to detect fatigue can facilitate an FES closed-loop controller design that considers the FES-induced muscle fatigue.

Effect of Customized Insoles on Gait in Post-Stroke Hemiparetic Individuals: A Randomized Controlled Trial

Background: Insoles have been widely applied to many diseases, but stroke involves complex problems and there is a paucity of research on the application of insoles in stroke patients. Aim: To evaluate the effect of customized insoles on gait in patients with hemiplegia. Design: A randomized controlled trial. Setting: Rehabilitation department of a hospital. Population: A total of 50 stroke patients were randomized into an experimental group (n = 25) or a control group (n = 25). Methods: Both groups received conventional gait training, which was conducted five times a week, every 40 min for four weeks and patients in the experimental group were required to wear customized insoles for at least 1 h per day for four weeks. The primary outcome measure was the Tinetti Gait Scale (TGS) and the secondary outcome measures were the plantar pressure test, 6-min walking test (6MWT), lower extremity Fugl-Meyer assessment (FMA-LE), Berg Balance Scale (BBS), and the modified Barthel index (MBI). Results: Compared to the control group, there were significant increases in the experimental group after four weeks (p = 0.014) and at the four week follow-up (p = 0.001) in the change in TGS, weight-bearing on the involved side (p = 0.012) or forefoot (p = 0.028) when standing, weight-bearing on the involved side (p = 0.01 6) or forefoot (p = 0.043) when walking, early stance phase (p = 0.023) and mid stance phase (p = 0.013) on the involved side, FMA-LE (p = 0.029), BBS (p = 0.005), and MBI (p = 0.009), but there were no differences in the late stance phase (p = 0.472) on the involved side when walking or in the 6MWT (p = 0.069). Conclusions: Customized insoles had great efficacy in enhancing gait performance in stroke patients.

Quantifying the Generation Process of Multi-Level Tactile Sensations via ERP Component Investigation

Humans obtain characteristic information such as texture and weight of external objects, relying on the brain's integration and classification of tactile information; however, the decoding mechanism of multi-level tactile information is relatively elusive from the temporal sequence. In this paper, nonvariant frequency, along with the variant pulse width of electrotactile stimulus, was performed to generate multi-level pressure sensation. Event-related potentials (ERPs) were measured to investigate the mechanism of whole temporal tactile processing. Five ERP components, containing P100-N140-P200-N200-P300, were observed. By establishing the relationship between stimulation parameters and ERP component amplitudes, we found the following: (1) P200 is the most significant component for distinguishing multi-level tactile sensations; (2) P300 is correlated well with the subjective judgment of tactile sensation. The temporal sequence of brain topographies was implemented to clarify the spatiotemporal characteristics of the tactile process, which conformed to the serial processing model in neurophysiology and cortical network response area described by fMRI. Our results can help further clarify the mechanism of tactile sequential processing, which can be applied to improve the tactile BCI performance, sensory enhancement, and clinical diagnosis for doctors to evaluate the tactile process disorders by examining the temporal ERP components.

Application of neuromuscular electrical stimulation on the support limb during reactive balance control in persons with stroke: a pilot study

The aim of the present study was to investigate the effect of the application of neuromuscular electrical stimulation to the quadriceps muscle of the paretic limb during externally induced stance perturbations on reactive balance control and on fall outcomes in people with chronic stroke. Ten participants experienced 12 stance treadmill perturbation trails, 6 forward balance perturbation trials and 6 backward balance perturbation trials. For each perturbation condition, three perturbation trials were delivered synchronized with neuromuscular electrical stimulation applied to the quadriceps of the paretic limb and three perturbation trials were delivered without stimulation. Behavioral outcome measures, such as incidence of laboratory falls and number of compensatory steps, kinematic outcome measures, such as margin of stability and minimum hip high values after the perturbation, step initiation time, step execution time and step length of the stepping leg were analyzed. The application of neuromuscular electrical stimulation on the paretic quadriceps between the range of 50 and 500 ms after stance forward and backward perturbations reduced the laboratory falls incidence (p < 0.05), improved stability values (p < 0.05) and reduced the hip height descent (p < 0.05) compared to the experimental condition in which participants were exposed to stance perturbations without neuromuscular electrical stimulation. Additionally, step initiation time of the recovery step was lower in neuromuscular electrical stimulation condition during the forward balance perturbation protocol. Our results showed that the application of neuromuscular electrical stimulation on the knee extensor muscles of the paretic limb reduces the incidence of laboratory falls, enhances reactive stability control and reduces vertical limb collapse after stance forward and backward perturbations in people with chronic stroke.

Neural decoding of gait phases during motor imagery and improvement of the decoding accuracy by concurrent action observation

Objective. Brain decoding of motor imagery (MI) not only is crucial for the control of neuroprosthesis but also provides insights into the underlying neural mechanisms. Walking consists of stance and swing phases, which are associated with different biomechanical and neural control features. However, previous knowledge on decoding the MI of gait is limited to simple information (e.g. the classification of 'walking' and 'rest').Approach. Here, we investigated the feasibility of electroencephalogram (EEG) decoding of the two gait phases during the MI of walking and whether the combined use of MI and action observation (AO) would improve decoding accuracy.Main results. We demonstrated that the stance and swing phases could be decoded from EEGs during MI or AO alone. We also demonstrated the decoding accuracy during MI was improved by concurrent AO. The decoding models indicated that the improved decoding accuracy following the combined use of MI and AO was facilitated by the additional information resulting from the concurrent cortical activations related to sensorimotor, visual, and action understanding systems associated with MI and AO.Significance. This study is the first to show that decoding the stance versus swing phases during MI is feasible. The current findings provide fundamental knowledge for neuroprosthetic design and gait rehabilitation, and they expand our understanding of the neural activity underlying AO, MI, and AO + MI of walking.Novelty and significanceBrain decoding of detailed gait-related information during motor imagery (MI) is important for brain-computer interfaces (BCIs) for gait rehabilitation. This study is the first to show the feasibility of EEG decoding of the stance versus swing phases during MI. We also demonstrated that the combined use of MI and action observation (AO) improves decoding accuracy, which is facilitated by the concurrent and synergistic involvement of the cortical activations for MI and AO. These findings extend the current understanding of neural activity and the combined effects of AO and MI and provide a basis for effective techniques for walking rehabilitation.

A Clinical Practice Guideline for the Use of Ankle-Foot Orthoses and Functional Electrical Stimulation Post-Stroke

BACKGROUND

Level of ambulation following stroke is a long-term predictor of participation and disability. Decreased lower extremity motor control can impact ambulation and overall mobility. The purpose of this clinical practice guideline (CPG) is to provide evidence to guide clinical decision-making for the use of either ankle-foot orthosis (AFO) or functional electrical stimulation (FES) as an intervention to improve body function and structure, activity, and participation as defined by the International Classification of Functioning, Disability and Health (ICF) for individuals with poststroke hemiplegia with decreased lower extremity motor control.

METHODS

A review of literature published through November 2019 was performed across 7 databases for all studies involving stroke and AFO or FES. Data extracted included time post-stroke, participant characteristics, device types, outcomes assessed, and intervention parameters. Outcomes were examined upon initial application and after training. Recommendations were determined on the basis of the strength of the evidence and the potential benefits, harm, risks, or costs of providing AFO or FES.

RESULTS/DISCUSSION

One-hundred twenty-two meta-analyses, systematic reviews, randomized controlled trials, and cohort studies were included. Strong evidence exists that AFO and FES can each increase gait speed, mobility, and dynamic balance. Moderate evidence exists that AFO and FES increase quality of life, walking endurance, and muscle activation, and weak evidence exists for improving gait kinematics. AFO or FES should not be used to decrease plantarflexor spasticity. Studies that directly compare AFO and FES do not indicate overall superiority of one over the other. But evidence suggests that AFO may lead to more compensatory effects while FES may lead to more therapeutic effects. Due to the potential for gains at any phase post-stroke, the most appropriate device for an individual may change, and reassessments should be completed to ensure the device is meeting the individual's needs.

LIMITATIONS

This CPG cannot address the effects of one type of AFO over another for the majority of outcomes, as studies used a variety of AFO types and rarely differentiated effects. The recommendations also do not address the severity of hemiparesis, and most studies included participants with varied baseline ambulation ability.

SUMMARY

This CPG suggests that AFO and FES both lead to improvements post-stroke. Future studies should examine timing of provision, device types, intervention duration and delivery, longer term follow-up, responders versus nonresponders, and individuals with greater impairments.

DISCLAIMER

These recommendations are intended as a guide for clinicians to optimize rehabilitation outcomes for people with poststroke hemiplegia who have decreased lower extremity motor control that impacts ambulation and overall mobility.A Video Abstract is available as supplemental digital content from the authors (available at: http://links.lww.com/JNPT/A335).

Functional electrical stimulation compared with ankle-foot orthosis in subacute post stroke patients with foot drop: A pilot study

Background: The conventional treatment for foot drop includes an ankle-foot orthosis (AFO) or functional electrical stimulation (FES). Goal: To compare gait parameters in patients following a subacute post stroke with foot drop treated with AFO or FES. Method: Twenty one subacute patients with stroke with foot drop were fitted with FES (N = 10) or AFO (N = 11). Evaluations were performed at baseline, following 4 weeks and 12 weeks. Spatiotemporal gait parameters and symmetry, dynamic electromyography, 10-m walk test, 6-min walk test, timed up and go, functional ambulation classification, and perception of improvement in walking were measured. The gait analysis measures were collected without the assistive devices while the functional measures were collected with them. Results: Both groups showed improvement in all of the outcome measures, with no between-groups differences. The swing duration's and step length's symmetry indicated better gait symmetry in the FES group after 12 weeks (p = 0.037, effect size = -0.538 and p = 0.028 effect size = -0.568, respectively). The FES group perceived significant improvement in gait after 4 weeks, while subjects in the AFO group reported to perceive improvement only after 12 weeks. Conclusions: Our findings suggest that FES is at least as effective as traditional AFO and may be more so.

Trends and Technologies in Rehabilitation of Foot Drop: A Systematic Review

INTRODUCTION

Foot Drop (FD) is a condition, which is very commonly found in post-stoke patients; however it can also be seen in patients with multiple sclerosis, and cerebral palsy. It is a sign of neuromuscular damage caused by the weakness of the muscles. There are various approaches of FD's rehabilitation, such as physiotherapy, surgery, and the use of technological devices. Recently, researchers have worked on developing various technologies to enhance assisting and rehabilitation of FD.

AREAS COVERED

This review analyzes different types of technologies available for FD. This include devices that are available commercially or still under research. 101 studies published between 2015 and 2020 were identified for the review, many were excluded due to various reasons, e.g., were not robot-based devices, did not include FD as one of the targeted diseases, or was insufficient information. 24 studies that met our inclusion criteria were assessed. These studies were further classified into two different categories: robot-based ankle-foot orthosis (RAFO) and Functional Electrical Stimulation (FES) devices.

EXPERT OPINION

Studies included showed that both RAFO and FES showed considerable improvement in the gait cycle of the patients. Future trends are inclining towards integrating FES with other neuro-concepts such as muscle-synergies for further developments.

Therapeutic effectiveness of a single exercise session combined with WalkAide functional electrical stimulation in post-stroke patients: a crossover design study

A growing body of evidence has suggested that the imbalance of epigenetic markers and oxidative stress appears to be involved in the pathophysiology and progression of stroke. Thus, strategies that modulate these biomarkers might be considered targets for neuroprotection and novel therapeutic opportunities for these patients. Physical exercise has been reported to induce changes in these epigenetic markers and improve clinical outcomes in different populations. However, little is reported on this in post-stroke patients. The purpose of this study was to investigate the effect of a single exercise session with WalkAide functional electrical stimulation (FES) on cognitive performance, clinical functional parameters, oxidative stress and epigenetic modulation in post-stroke individuals. In this crossover design study, 12 post-stroke individuals aged 54–72 years of either sexes were included and subjected to a single session of exercise (45 minutes) without WalkAide functional electrical stimulation (EXE alone group), followed by another single session of exercise (45 minutes) with WalkAide functional electrical stimulation (EXE + FES group). The clinical functional outcome measures, cognitive performance and blood collections for biomarker measurements were assessed pre- and post-intervention. After intervention, higher Berg Balance Scale scores were obtained in the EXE + FES group than in the EXE alone group. There was no significant difference in the Timed Up and Go test results post-intervention between EXE alone and EXE + FES groups. After intervention, a better cognitive performance was found in both groups compared with before the intervention. After intervention, the Timed Up and Go test scores were higher in the EXE + FES group than in the EXE alone group. In addition, the intervention induced lower levels of lipid peroxidation. After intervention, carbonyl level was lower, superoxide dismutase activity and superoxide dismutase/catalase activity ratio were higher in the EXE + FES group, compared with the EXE group alone. In each group, both histone deacetylase (HDAC2) and histone acetyltransferase activities were increased after intervention compared with before the intervention. These findings suggest that a single exercise session with WalkAide FES is more effective on balance ability and cognitive performance compared with conventional exercise alone in post-stroke patients. This is likely to be related to the regulation of oxidative stress markers. The present study was approved by the Research Ethics Committee of the Methodist University Center-IPA (approval No. 2.423.376) on December 7, 2017 and registered in the Brazilian Registry of Clinical Trials—ReBEC (RBR-9phj2q) on February 11, 2019.

Toward a hybrid exoskeleton for crouch gait in children with cerebral palsy: neuromuscular electrical stimulation for improved knee extension

BACKGROUND

Neuromuscular Electrical Stimulation (NMES) has been utilized for many years in cerebral palsy (CP) with limited success despite its inherent potential for improving muscle size and/or strength, inhibiting or reducing spasticity, and enhancing motor performance during functional activities such as gait. While surface NMES has been shown to successfully improve foot drop in CP and stroke, correction of more complex gait abnormalities in CP such as flexed knee (crouch) gait remains challenging due to the level of stimulation needed for the quadriceps muscles that must be balanced with patient tolerability and the ability to deliver NMES assistance at precise times within a gait cycle.

METHODS

This paper outlines the design and evaluation of a custom, noninvasive NMES system that can trigger and adjust electrical stimulation in real-time. Further, this study demonstrates feasibility of one possible application for this digitally-controlled NMES system as a component of a pediatric robotic exoskeleton to provide on-demand stimulation to leg muscles within specific phases of the gait cycle for those with CP and other neurological disorders who still have lower limb sensation and volitional control. A graphical user interface was developed to digitally set stimulation parameters (amplitude, pulse width, and frequency), timing, and intensity during walking. Benchtop testing characterized system delay and power output. System performance was investigated during a single session that consisted of four overground walking conditions in a 15-year-old male with bilateral spastic CP, GMFCS Level III: (1) his current Ankle-Foot Orthosis (AFO); (2) unassisted Exoskeleton; (3) NMES of the vastus lateralis; and (4) NMES of the vastus lateralis and rectus femoris. We hypothesized in this participant with crouch gait that NMES triggered with low latency to knee extensor muscles during stance would have a modest but positive effect on knee extension during stance.

RESULTS

The system delivers four channels of NMES with average delays of 16.5 ± 13.5 ms. Walking results show NMES to the vastus lateralis and rectus femoris during stance immediately improved mean peak knee extension during mid-stance (p = 0.003*) and total knee excursion (p = 0.009*) in the more affected leg. The electrical design, microcontroller software and graphical user interface developed here are included as open source material to facilitate additional research into digitally-controlled surface stimulation ( github.com/NIHFAB/NMES ).

CONCLUSIONS

The custom, digitally-controlled NMES system can reliably trigger electrical stimulation with low latency. Precisely timed delivery of electrical stimulation to the quadriceps is a promising treatment for crouch. Our ultimate goal is to synchronize NMES with robotic knee extension assistance to create a hybrid NMES-exoskeleton device for gait rehabilitation in children with flexed knee gait from CP as well as from other pediatric disorders.

TRIAL REGISTRATION

clinicaltrials.gov, ID: NCT01961557 . Registered 11 October 2013; Last Updated 27 January 2020.

Functional Electrical Stimulation Controlled by Motor Imagery Brain-Computer Interface for Rehabilitation

Sensorimotor rhythm (SMR)-based brain–computer interface (BCI) controlled Functional Electrical Stimulation (FES) has gained importance in recent years for the rehabilitation of motor deficits. However, there still remain many research questions to be addressed, such as unstructured Motor Imagery (MI) training procedures; a lack of methods to classify different MI tasks in a single hand, such as grasping and opening; and difficulty in decoding voluntary MI-evoked SMRs compared to FES-driven passive-movement-evoked SMRs. To address these issues, a study that is composed of two phases was conducted to develop and validate an SMR-based BCI-FES system with 2-class MI tasks in a single hand (Phase 1), and investigate the feasibility of the system with stroke and traumatic brain injury (TBI) patients (Phase 2). The results of Phase 1 showed that the accuracy of classifying 2-class MIs (approximately 71.25%) was significantly higher than the true chance level, while that of distinguishing voluntary and passive SMRs was not. In Phase 2, where the patients performed goal-oriented tasks in a semi-asynchronous mode, the effects of the FES existence type and adaptive learning on task performance were evaluated. The results showed that adaptive learning significantly increased the accuracy, and the accuracy after applying adaptive learning under the No-FES condition (61.9%) was significantly higher than the true chance level. The outcomes of the present research would provide insight into SMR-based BCI-controlled FES systems that can connect those with motor disabilities (e.g., stroke and TBI patients) to other people by greatly improving their quality of life. Recommendations for future work with a larger sample size and kinesthetic MI were also presented.

Functional electrical stimulation of the peroneal nerve improves post-stroke gait speed when combined with physiotherapy. A systematic review and meta-analysis

BACKGROUND

Functional electrical stimulation (FES) applied to the paretic peroneal nerve has positive clinical effects on foot drop secondary to stroke.

OBJECTIVE

To evaluate the effectiveness of FES applied to the paretic peroneal nerve on gait speed, active ankle dorsiflexion mobility, balance, and functional mobility.

METHODS

Electronic databases were searched for articles published from inception to January 2020. We included randomized controlled trials or crossover trials focused on determining the effects of FES combined or not with other therapies in individuals with foot drop after stroke. Characteristics of studies, participants, comparison groups, interventions, and outcomes were extracted. Statistical heterogeneity was assessed with the I² statistic.

RESULTS

We included 14 studies providing data for 1115 participants. FES did not enhance gait speed as compared with conventional treatments (i.e., supervised/unsupervised exercises and regular activities at home). FES combined with supervised exercises (i.e., physiotherapy) was better than supervised exercises alone for improving gait speed. We found no effect of FES combined with unsupervised exercises and inconclusive effects when FES was combined with regular activities at home. When FES was compared with conventional treatments, it improved ankle dorsiflexion, balance and functional mobility, albeit with high heterogeneity for these last 2 outcomes.

CONCLUSIONS

This meta-analysis revealed low quality of evidence for positive effects of FES on gait speed when combined with physiotherapy. FES can improve ankle dorsiflexion, balance, and functional mobility. However, considering the low quality of evidence and the high heterogeneity, these results must be interpreted carefully.

Advances in neuroprosthetic management of foot drop: a review

This paper reviews the technological advances and clinical results obtained in the neuroprosthetic management of foot drop. Functional electrical stimulation has been widely applied owing to its corrective abilities in patients suffering from a stroke, multiple sclerosis, or spinal cord injury among other pathologies. This review aims at identifying the progress made in this area over the last two decades, addressing two main questions: What is the status of neuroprosthetic technology in terms of architecture, sensorization, and control algorithms?. What is the current evidence on its functional and clinical efficacy? The results reveal the importance of systems capable of self-adjustment and the need for closed-loop control systems to adequately modulate assistance in individual conditions. Other advanced strategies, such as combining variable and constant frequency pulses, could also play an important role in reducing fatigue and obtaining better therapeutic results. The field not only would benefit from a deeper understanding of the kinematic, kinetic and neuromuscular implications and effects of more promising assistance strategies, but also there is a clear lack of long-term clinical studies addressing the therapeutic potential of these systems. This review paper provides an overview of current system design and control architectures choices with regard to their clinical effectiveness. Shortcomings and recommendations for future directions are identified.

Implanted High Density Cuff Electrodes Functionally Activate Human Tibial and Peroneal Motor Units Without Chronic Detriment to Peripheral Nerve Health

OBJECTIVE

Peripheral nerve stimulation via multi-contact nerve cuff electrodes (NCEs) has proved effective in restoring function to individuals with lower-extremity paralysis. This study investigates clinical measures of nerve health over one year post-implantation of a composite flat-interface nerve electrode (C-FINE) on the tibial and peroneal nerves above the knee in a human volunteer. This represents the first deployment of a novel NCE on new neural targets in a uniquely challenging location prone to prolonged externally applied forces, making acute and chronic postoperative observation critical.

MATERIALS AND METHODS

A 27-year-old man with an incomplete spinal cord injury (AIS C) at the C3 to C4 level received eight-contact C-FINEs bilaterally on the tibial and peroneal nerves, proximal to the knee. Access to four contacts per cuff exhibiting the most desirable responses was externalized via temporary percutaneous leads. Percutaneous leads were later removed, with contacts generating the best dorsiflexion (two of four) and plantar flexion (one of four) reconnected to a permanently implanted pulse generator. For 13 months post-implantation, nerve health and cuff performance were assessed through motor nerve conduction velocity (MNCV) studies, clinical needle electromyography, compound motor action potential (CMAP), sensory nerve action potential (SNAP), stimulation-evoked tetanic moment collection, and lower-limb circumference measurements.

RESULTS

Tibial and peroneal MNCVs remained stable bilaterally above 40 m/sec, with CMAPs increased or stable after six months. SNAPs remained stable across all measurements. CMAP initial charge thresholds remained below 50 nC, with minimal changes to muscle recruitment order in three of four externalized contacts per cuff. Peak tetanic moments remained stable, with bilateral increases in thigh and calf circumferences of 5% and 14% over one year.

CONCLUSIONS

Above-knee tibial and peroneal NCEs can restore stimulated ankle-joint function without chronic nerve health detriments. Alongside previous femoral nerve data, this study demonstrates the ability of NCEs to enhance lower-extremity function with limited neuromuscular impact.

Motor neuroprosthesis for promoting recovery of function after stroke

BACKGROUND

Motor neuroprosthesis (MN) involves electrical stimulation of neural structures by miniaturized devices to allow the performance of tasks in the natural environment in which people live (home and community context), as an orthosis. In this way, daily use of these devices could act as an environmental facilitator for increasing the activities and participation of people with stroke.

OBJECTIVES

To assess the effects of MN for improving independence in activities of daily living (ADL), activities involving limbs, participation scales of health-related quality of life (HRQoL), exercise capacity, balance, and adverse events in people after stroke.

SEARCH METHODS

We searched the Cochrane Stroke Group Trials Register (searched 19 August 2019), the Cochrane Central Register of Controlled Trials (CENTRAL) (August 2019), MEDLINE (1946 to 16 August 2019), Embase (1980 to 19 August 2019), and five additional databases. We also searched trial registries, databases, and websites to identify additional relevant published, unpublished, and ongoing trials.

SELECTION CRITERIA

Randomized controlled trials (RCTs) and randomized controlled cross-over trials comparing MN for improving activities and participation versus other assistive technology device or MN without electrical stimulus (stimulator is turned off), or no treatment, for people after stroke.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials, extracted data, and assessed risk of bias of the included studies. Any disagreements were resolved through discussion with a third review author. We contacted trialists for additional information when necessary and performed all analyses using Review Manager 5. We used GRADE to assess the certainty of the evidence.

MAIN RESULTS

We included four RCTs involving a total of 831 participants who were more than three months poststroke. All RCTs were of MN that applied electrical stimuli to the peroneal nerve. All studies included conditioning protocols to adapt participants to MN use, after which participants used MN from up to eight hours per day to all-day use for ambulation in daily activities performed in the home or community context. All studies compared the use of MN versus another assistive device (ankle-foot orthosis [AFO]). There was a high risk of bias for at least one assessed domain in three of the four included studies. No studies reported outcomes related to independence in ADL. There was low-certainty evidence that AFO was more beneficial than MN on activities involving limbs such as walking speed until six months of device use (mean difference (MD) -0.05 m/s, 95% confidence interval (CI) -0.10 to -0.00; P = 0.03; 605 participants; 2 studies; I² = 0%; low-certainty evidence); however, this difference was no longer present in our sensitivity analysis (MD -0.07 m/s, 95% CI -0.16 to 0.02; P = 0.13; 110 participants; 1 study; I² = 0%). There was low to moderate certainty that MN was no more beneficial than AFO on activities involving limbs such as walking speed between 6 and 12 months of device use (MD 0.00 m/s, 95% CI -0.05 to 0.05; P = 0.93; 713 participants; 3 studies; I² = 17%; low-certainty evidence), Timed Up and Go (MD 0.51 s, 95% CI -4.41 to 5.43; P = 0.84; 692 participants; 2 studies; I² = 0%; moderate-certainty evidence), and modified Emory Functional Ambulation Profile (MD 14.77 s, 95% CI -12.52 to 42.06; P = 0.29; 605 participants; 2 studies; I² = 0%; low-certainty evidence). There was no significant difference in walking speed when MN was delivered with surface or implantable electrodes (test for subgroup differences P = 0.09; I² = 65.1%). For our secondary outcomes, there was very low to moderate certainty that MN was no more beneficial than another assistive device for participation scales of HRQoL (standardized mean difference 0.26, 95% CI -0.22 to 0.74; P = 0.28; 632 participants; 3 studies; I² = 77%; very low-certainty evidence), exercise capacity (MD -9.03 m, 95% CI -26.87 to 8.81; P = 0.32; 692 participants; 2 studies; I² = 0%; low-certainty evidence), and balance (MD -0.34, 95% CI -1.96 to 1.28; P = 0.68; 692 participants; 2 studies; I² = 0%; moderate-certainty evidence). Although there was low- to moderate-certainty evidence that the use of MN did not increase the number of serious adverse events related to intervention (risk ratio (RR) 0.35, 95% CI 0.04 to 3.33; P = 0.36; 692 participants; 2 studies; I² = 0%; low-certainty evidence) or number of falls (RR 1.20, 95% CI 0.92 to 1.55; P = 0.08; 802 participants; 3 studies; I² = 33%; moderate-certainty evidence), there was low-certainty evidence that the use of MN in people after stroke may increase the risk of participants dropping out during the intervention (RR 1.48, 95% CI 1.11 to 1.97; P = 0.007; 829 participants; 4 studies; I² = 0%).

AUTHORS' CONCLUSIONS

Current evidence indicates that MN is no more beneficial than another assistive technology device for improving activities involving limbs measured by Timed Up and Go, balance (moderate-certainty evidence), activities involving limbs measured by walking speed and modified Emory Functional Ambulation Profile, exercise capacity (low-certainty evidence), and participation scale of HRQoL (very low-certainty evidence). Evidence was insufficient to estimate the effect of MN on independence in ADL. In comparison to other assistive devices, MN does not appear to increase the number of falls (moderate-certainty evidence) or serious adverse events (low-certainty evidence), but may result in a higher number of dropouts during intervention period (low-certainty evidence).

Comfortable walking speed and energy cost of locomotion in patients with multiple sclerosis

Comfortable walking speed and energy cost of walking are physiological markers of metabolic activity during gait. People with multiple sclerosis are characterized by altered gait biomechanics and energetics, related to the degree of disability and spasticity, which lead to an increased energy cost of walking. Several studies concerning the energy cost of walking in multiple sclerosis have been published. Nevertheless, differences in protocols and characteristics of the sample have led to different outcomes. The aim of the present meta-analysis is to summarize results from studies with specific inclusion characteristics, and to present data about the comfortable walking speed and the energy cost of walking at that speed. Moreover, a detailed discussion of the potential mechanisms involved in the altered metabolic activity during exercise was included. A total of 19 studies were considered, 12 of which were also part of the quantitative analysis. Despite the strict selection process, high between-group heterogeneity was found for both outcomes. Nevertheless, the overall results suggest a pooled mean comfortable walking speed of 1.12 m/s (95% CI 1.05-1.18) and energy cost of 0.19 mLO₂/kg/m (95% CI 0.17-0.21). These findings support the results of previous studies suggesting that energy cost of walking may be increased by 2-3 times compared to healthy controls (HC), and encourage the use of this marker in association with other parameters of the disease.

Correlation Between Muscle Structures and Electrical Properties of the Tibialis Anterior in Subacute Stroke Survivors: A Pilot Study

Electrical impedance myography (EIM) is a non-invasive diagnostic tool that assesses the muscle inherent properties, whereas ultrasonography can assess the alteration in muscle architecture. This study aimed to combine EIM with ultrasonography to assess the changes of the tibialis anterior (TA) muscle properties during passive plantar/dorsiflexion in stroke survivors. Fifteen patients with subacute stroke were recruited. The muscle structures were simultaneously assessed by EIM and ultrasonography at five different extension angles (−10°, 0°, 10°, 20°, and 30°) of the ankle joint. The EIM parameters measured were resistance (R), reactance (X), and phase angle (θ). The parameters recorded by ultrasonography were pennation angle (PA), muscle thickness (MT), and fascicle length (FL). Two-way repeated ANOVA was performed to compare the differences between the affected and unaffected sides as well as the parameters that changed with joint angle. Linear correlation analysis was conducted to assess the association between muscle parameters and clinical scores. The results showed that as the ankle was passively plantarflexed, the θ (P = 0.003) and PA (P < 0.001) values decreased, and the X (P < 0.001), R (P < 0.001), and FL (P < 0.001) values increased. Significant correlations were found between the FL and R values (r = 0.615, P = 0.015), MT and R values (r = 0.522, P = 0.046), and FL and θ values (r = 0.561, P = 0.03), as well as between the PA and the Fugl–Meyer Assessment of Lower Extremity score (r = 0.615, P = 0.015), the R and the Modified Ashworth Scale (MAS) score (r = 0.58, P = 0.023), and the PA and the manual muscle testing (MMT) score (r = −0.575, P = 0.025). This study demonstrated a correlation between the EIM and the ultrasonography parameters at different joint angles. Therefore, both methods could jointly be applied in patients with stroke to detect changes in the muscle inherent properties and muscle architecture. This could assist clinicians to quantitatively evaluate the muscle condition in people with subacute stroke. The study was registered on the Chinese Clinical Trial Registry (trial registration number: ChiCTR-IOR-17012299, http://www.chictr.org.cn/showprojen.aspx?proj=19818).

Clinical Trial Registration Number: ChiCTR-IOR-17012299.

A Neuro-Prosthetic Device for Substituting Sensory Functions during Stance Phase of the Gait

In this study, we present the experimental results demonstrating the functionality of our recently developed “balancing device” for walking restoration in patients with spinal cord injuries. Since we are preparing this device for testing on dogs, we program the analytical core of the device to recognize both stance and swing phases of the dog gait, the direction that the dog is falling, as well as selecting a suitable balancing strategy to prevent falling. The analytical core of the device is a commercial microcontroller, the Teensy, which is able to provide suitable stimulation commands and intensities as a voltage for delivery to the stimulation circuit and target muscles. We show the functional schematic of the device along with experimental results obtained by testing the device in a simulated robotic dog. Results show that the sensory system of the animal lost by spinal cord injury can be replaced by the sensing core of the device and the analytical core can provide appropriate stimulation control to balance the body of a dog. All test results are obtained using our robot test-bed and living animals are not involved in this study.

Immediate effect of a wearable foot drop stimulator to prevent foot drop on the gait ability of patients with hemiplegia after stroke

The purpose of this study was to compare the effects of a foot drop stimulator (FDS) and ankle-foot orthosis (AFO) on the gait ability of patients with hemiplegia after stroke. This study recruited 10 patients with hemiplegia after stroke. All patients performed gait under two conditions (AFO and FDS gait). Gait parameters were measured with the GAITRite® system to analyze the spatial and temporal parameters of the patients' gaits. No significant differences in cadence, velocity, swing time, stance time, or step length of the affected or less-affected limbs were found between the two conditions (all, p > .05). These findings demonstrate that AFO and FDS have a similar effect on the gait ability of patients with hemiplegia after stroke.

Long-term outcomes of semi-implantable functional electrical stimulation for central drop foot

BACKGROUND

Central drop foot is a common problem in patients with stroke or multiple sclerosis (MS). For decades, it has been treated with orthotic devices, keeping the ankle in a fixed position. It has been shown recently that semi-implantable functional electrical stimulation (siFES) of the peroneal nerve can lead to a greater gait velocity increase than orthotic devices immediately after being switched on. Little is known, however, about long-term outcomes over 12 months, and the relationship between quality of life (QoL) and gait speed using siFES has never been reported applying a validated tool. We provide here a report of short (3 months) and long-term (12 months) outcomes for gait speed and QoL.

METHODS

Forty-five consecutive patients (91% chronic stroke, 9% MS) with central drop foot received siFES (Actigait®). A 10 m walking test was carried out on day 1 of stimulation (T1), in stimulation ON and OFF conditions, and repeated after 3 (T2) and 12 (T3) months. A 36-item Short Form questionnaire was applied at all three time points.

RESULTS

We found a main effect of stimulation on both maximum (p < 0.001) and comfortable gait velocity (p < 0.001) and a main effect of time (p = 0.015) only on maximum gait velocity. There were no significant interactions. Mean maximum gait velocity across the three assessment time points was 0.13 m/s greater with stimulation ON than OFF, and mean comfortable gait velocity was 0.083 m/s faster with stimulation ON than OFF. The increase in maximum gait velocity over time was 0.096 m/s, with post hoc testing revealing a significant increase from T1 to T2 (p = 0.012), which was maintained but not significantly further increased at T3. QoL scores showed a main effect of time (p < 0.001), with post hoc testing revealing an increase from T1 to T2 (p < 0.001), which was maintained at T3 (p < 0.001). Finally, overall absolute QoL scores correlated with the absolute maximum and comfortable gait speeds at T2 and T3, and the increase in overall QoL scores correlated with the increase in comfortable gait velocity from T1 to T3. Pain was reduced at T2 (p < 0.001) and was independent of gait speed but correlated with overall QoL (p < 0.001).

CONCLUSIONS

Peroneal siFES increased maximal and comfortable gait velocity and QoL, with the greatest increase in both over the first three months, which was maintained at one year, suggesting that 3 months is an adequate follow-up time. Pain after 3 months correlated with QoL and was independent of gait velocity, suggesting pain as an independent outcome measure in siFES for drop foot.

Surplus value of implanted peroneal functional electrical stimulation over ankle-foot orthosis for gait adaptability in people with foot drop after stroke

BACKGROUND

Implanted peroneal functional electrical stimulation (FES) is an effective alternative treatment to ankle-foot orthosis (AFO) in people with drop foot after stroke. With FES no constraints on ankle mobility are imposed which might particularly be exploited in challenging walking environments that require adaptations of the gait pattern to environmental disturbances.

RESEARCH QUESTION

Is gait adaptability, by means of the capacity to avoid sudden obstacles while walking on a treadmill, superior with implanted FES compared to AFO in people with drop foot after stroke?

METHODS

A 4-channel peroneal nerve stimulator (ActiGait®) was implanted in 22 persons with stroke (>6 months) who regularly used an AFO. Gait adaptability was tested with an obstacle avoidance task on an instrumented treadmill up to 26 weeks (n = 10) or 52 weeks (n = 12) after FES-system activation. At assessments, 30 trials, in which obstacles were suddenly dropped onto the treadmill in front of the paretic leg, were recorded with each device (FES / AFO). Trials were grouped by available response times (ART) and success rates were calculated. The effect of device, ART and follow up time on success rates was tested using generalized estimated equations. Nonparametric correlations were calculated to associate changes in success rates with clinimetrics.

RESULTS

Success rates of obstacle avoidance were higher when participants used their FES system compared to AFO (Δ4.7%, p = 0.03), which effect was largest for longest ARTs (Δ15%, p = 0.03). Participants with greater motor impairment of the paretic leg showed greater benefit from FES (r_s=-0.49, p = 0.04).

SIGNIFICANCE

FES has been found equally effective as AFO in improving walking speed of people with drop foot after stroke. We now present superior walking performance in a complex walking environment for implanted peroneal FES compared to AFO. These findings underline the importance of using gait assessments that require interplay with the environment, besides assessment of stationary walking, in community ambulators.

The long-term effects of an implantable drop foot stimulator on gait in hemiparetic patients

Drop foot is a frequent abnormality in gait after central nervous system lesions. Different treatment strategies are available to functionally restore dorsal extension during swing phase in gait. Orthoses as well as surface and implantable devices for electrical stimulation of the peroneal nerve may be used in patients who do not regain good dorsal extension. While several studies investigated the effects of implanted systems on walking speed and gait endurance, only a few studies have focussed on the system’s impact on kinematics and long-term outcomes. Therefore, our aim was to further investigate the effects of the implanted system ActiGait on gait kinematics and spatiotemporal parameters for the first time with a 1-year follow-up period. 10 patients were implanted with an ActiGait stimulator, with 8 patients completing baseline and follow-up assessments. Assessments included a 10-m walking test, video-based gait analysis and a Visual Analogue Scale (VAS) for health status. At baseline, gait analysis was performed without any assistive device as well as with surface electrical stimulation. At follow-up patients walked with the ActiGait system switched off and on. The maximum dorsal extension of the ankle at initial contact increased significantly between baseline without stimulation and follow-up with ActiGait (p = 0.018). While the spatio-temporal parameters did not seem to change much with the use of ActiGait in convenient walking speed, patients did walk faster when using surface stimulation or ActiGait compared to no stimulation at the 10-m walking test at their fastest possible walking speed. Patients rated their health better at the 1-year follow-up. In summary, a global improvement in gait kinematics compared to no stimulation was observed and the long-term safety of the device could be confirmed.

Gait Rehabilitation Using Functional Electrical Stimulation Induces Changes in Ankle Muscle Coordination in Stroke Survivors: A Preliminary Study

Background: Previous studies have demonstrated that post-stroke gait rehabilitation combining functional electrical stimulation (FES) applied to the ankle muscles during fast treadmill walking (FastFES) improves gait biomechanics and clinical walking function. However, there is considerable inter-individual variability in response to FastFES. Although FastFES aims to sculpt ankle muscle coordination, whether changes in ankle muscle activity underlie observed gait improvements is unknown. The aim of this study was to investigate three cases illustrating how FastFES modulates ankle muscle recruitment during walking.

Methods: We conducted a preliminary case series study on three individuals (53–70 y; 2 M; 35–60 months post-stroke; 19–22 lower extremity Fugl-Meyer) who participated in 18 sessions of FastFES (3 sessions/week; ClinicalTrials.gov: NCT01668602). Clinical walking function (speed, 6-min walk test, and Timed-Up-and-Go test), gait biomechanics (paretic propulsion and ankle angle at initial-contact), and plantarflexor (soleus)/dorsiflexor (tibialis anterior) muscle recruitment were assessed pre- and post-FastFES while walking without stimulation.

Results:Two participants (R1, R2) were categorized as responders based on improvements in clinical walking function. Consistent with heterogeneity of clinical and biomechanical changes commonly observed following gait rehabilitation, how muscle activity was altered with FastFES differed between responders. R1 exhibited improved plantarflexor recruitment during stance accompanied by increased paretic propulsion. R2 exhibited improved dorsiflexor recruitment during swing accompanied by improved paretic ankle angle at initial-contact. In contrast, the third participant (NR1), classified as a non-responder, demonstrated increased ankle muscle activity during inappropriate phases of the gait cycle. Across all participants, there was a positive relationship between increased walking speeds after FastFES and reduced SOL/TA muscle coactivation.

Conclusion:Our preliminary case series study is the first to demonstrate that improvements in ankle plantarflexor and dorsiflexor muscle recruitment (muscles targeted by FastFES) accompanied improvements in gait biomechanics and walking function following FastFES in individuals post-stroke. Our results also suggest that inducing more appropriate (i.e., reduced) ankle plantar/dorsi-flexor muscle coactivation may be an important neuromuscular mechanism underlying improvements in gait function after FastFES training, suggesting that pre-treatment ankle muscle status could be used for inclusion into FastFES. The findings of this case-series study, albeit preliminary, provide the rationale and foundations for larger-sample studies using similar methodology.

A Pilot RCT Investigating the Effects of Targeted Compression on Athletes With Pelvic/Groin Pain

CONTEXT

Athletic pelvic/groin pain is a common yet often challenging problem to both diagnose and manage. A new tool has been developed based on the clinical effects of applied force on the pelvis. Early findings indicate that this customized compression orthosis may have a positive effect on pelvic/groin pain and performance measures.

OBJECTIVES

To inform the design and test the practicality of procedures for a future definitively powered randomized controlled trial and to provide an estimate of the effect size of this orthosis on selected clinical and performance measures.

DESIGN

Pilot randomized controlled trial with participants randomly allocated to an intervention or waiting-list control group.

SETTING

The training location of each athlete.

PARTICIPANTS

24 athletes with subacute and chronic pelvic conditions were proposed to be recruited.

INTERVENTION

A customized compression orthosis, delivering targeted compression to the pelvic girdle.

OUTCOME MEASURES

Measures were the active straight leg raise (ASLR) test, squeeze test, broad jump, and the multiple single-leg hop-stabilization test.

RESULTS

A total of 16 athletes completed the study. The invention group demonstrated moderate to large estimated effect sizes on the squeeze test and active straight leg raise tests (d = 0.6-1.1) while wearing the orthosis. Small effect sizes (d = 0.2) were seen on jump distance and the dominant leg balance score. Compared with the control group, the intervention group also showed moderate to large estimated effect sizes on the active straight leg raise measures (d = 0.5-0.9) when wearing sports shorts.

CONCLUSIONS

The protocol was feasible. Effect sizes and recruitment/attrition rates suggest that the intervention holds promise and that a future definitively powered randomized controlled trial appears feasible and is indicated.

Cyclogram based Joint Symmetry Assessment after Utilization of a Foot Drop Stimulator during Post Stroke Hemiplegic Gait

In the absence of standardized symmetry assessments, quantifying symmetry based on the kinematic evolution of lower extremity joints can elucidate gait irregularities. The objective was to develop a novel cyclogram based symmetry (CBS) method to quantify lower extremity joints' symmetry and assess the effect of 6-month utilization of foot drop stimulator (FDS) on CBS of the lower limbs during hemiplegic gait post stroke. Twenty-four participants (13 stroke and 11 healthy controls (HC)) performed 10 walking trials at a free cadence on level ground. Symmetry values were computed using geometric properties of bilateral cyclograms obtained from normalized sagittal ankle, knee and hip kinematics. CBS and traditional temporospatial symmetry values were compared between the two groups using independent sample t-test. Effect of FDS utilization on symmetry was assessed by paired sample t- test computed at baseline and 6-month follow up. The CBS method successfully showed that the HC group was significantly more symmetrical at the ankle (p=0.001), knee (p=0.001) and hip (p<0.005) compared with the stroke group. The stroke group showed significant increment in hip symmetry with FDS at baseline but did not show any significant CBS changes at follow up. Pearson correlations revealed that hip and knee CBS had a significant influence on overall walking speed. The CBS method presents a unique approach to calculate symmetry based on the kinematics of lower extremities during gait.

Biomechanical mechanisms underlying exosuit-induced improvements in walking economy after stroke

Stroke-induced hemiparetic gait is characteristically asymmetric and metabolically expensive. Weakness and impaired control of the paretic ankle contribute to reduced forward propulsion and ground clearance - walking subtasks critical for safe and efficient locomotion. Targeted gait interventions that improve paretic ankle function after stroke are therefore warranted. We have developed textile-based, soft wearable robots that transmit mechanical power generated by off-board or body-worn actuators to the paretic ankle using Bowden cables (soft exosuits) and have demonstrated the exosuits can overcome deficits in paretic limb forward propulsion and ground clearance, ultimately reducing the metabolic cost of hemiparetic walking. This study elucidates the biomechanical mechanisms underlying exosuit-induced reductions in metabolic power. We evaluated the relationships between exosuit-induced changes in the body center of mass (COM) power generated by each limb, individual joint power and metabolic power. Compared with walking with an exosuit unpowered, exosuit assistance produced more symmetrical COM power generation during the critical period of the step-to-step transition (22.4±6.4% more symmetric). Changes in individual limb COM power were related to changes in paretic (R2=0.83, P=0.004) and non-paretic (R2=0.73, P=0.014) ankle power. Interestingly, despite the exosuit providing direct assistance to only the paretic limb, changes in metabolic power were related to changes in non-paretic limb COM power (R2=0.80, P=0.007), not paretic limb COM power (P>0.05). These findings contribute to a fundamental understanding of how individuals post-stroke interact with an exosuit to reduce the metabolic cost of hemiparetic walking.

Interventions to Improve Movement and Functional Outcomes in Adult Stroke Rehabilitation: Review and Evidence Summary

Background

Patients who have had a stroke may not be familiar with the terminology nor have the resources to efficiently search for evidence-based rehabilitation therapies to restore movement and functional outcomes. Recognizing that a thorough systematic review on this topic is beyond the scope of this article, we conducted a rapid review evidence summary to determine the level of evidence for common rehabilitation interventions to improve movement/motor and functional outcomes in adults who have had a stroke.

Objective

The objective of this study was to find evidence for common rehabilitation interventions to improve movement/motor and functional outcomes in adults who have had a stroke.

Methods

Medline Complete, PubMed, CINAHL Complete, Cochrane Database, Rehabilitation and Sports Medicine Source, Dissertation Abstracts International, and National Guideline Clearinghouse, from 1996 to April of 2016, were searched. From 348 articles, 173 met the following inclusion criteria: (1) published systematic reviews or meta-analyses, (2) outcomes target functional movement or motor skills of the upper and lower limbs, (3) non-pharmacological interventions that are commonly delivered to post-stroke population (acute and chronic), (4) human studies, and (5) English. Evidence tables were created to analyze the findings of systematic reviews and meta-analyses by category of interventions and outcomes.

Results

This rapid review found that the following interventions possess credible evidence to improve functional movement of persons with stroke: cardiorespiratory training, therapeutic exercise (ie, strengthening), task-oriented training (task-specific training), constraint-induced movement therapy (CIMT), mental practice, and mirror therapy. Neuromuscular electrical stimulation (NMES) (ie, functional electrical stimulation) shows promise as an intervention for stroke survivors.

Conclusions

Most commonly delivered therapeutic interventions to improve motor recovery after a stroke possess moderate quality evidence and are effective. Future research recommendations, such as optimal timing and dosage, would help rehabilitation professionals tailor interventions to achieve the best outcomes for stroke survivors.

Neuromuscular Electrical Stimulation for Treatment of Muscle Impairment: Critical Review and Recommendations for Clinical Practice

Purpose: In response to requests from physiotherapists for guidance on optimal stimulation of muscle using neuromuscular electrical stimulation (NMES), a review, synthesis, and extraction of key data from the literature was undertaken by six Canadian physical therapy (PT) educators, clinicians, and researchers in the field of electrophysical agents. The objective was to identify commonly treated conditions for which there was a substantial body of literature from which to draw conclusions regarding the effectiveness of NMES. Included studies had to apply NMES with visible and tetanic muscle contractions. Method: Four electronic databases (CINAHL, Embase, PUBMED, and SCOPUS) were searched for relevant literature published between database inceptions until May 2015. Additional articles were identified from bibliographies of the systematic reviews and from personal collections. Results: The extracted data were synthesized using a consensus process among the authors to provide recommendations for optimal stimulation parameters and application techniques to address muscle impairments associated with the following conditions: stroke (upper or lower extremity; both acute and chronic), anterior cruciate ligament reconstruction, patellofemoral pain syndrome, knee osteoarthritis, and total knee arthroplasty as well as critical illness and advanced disease states. Summaries of key details from each study incorporated into the review were also developed. The final sections of the article outline the recommended terminology for describing practice using electrical currents and provide tips for safe and effective clinical practice using NMES. Conclusion: This article provides physiotherapists with a resource to enable evidence-informed, effective use of NMES for PT practice.

Alterations in Spectral Attributes of Surface Electromyograms after Utilization of a Foot Drop Stimulator during Post-Stroke Gait

BACKGROUND

A foot drop stimulator (FDS) is a rehabilitation intervention that stimulates the common peroneal nerve to facilitate ankle dorsiflexion at the appropriate time during post-stroke hemiplegic gait. Time-frequency analysis (TFA) of non-stationary surface electromyograms (EMG) and spectral variables such as instantaneous mean frequency (IMNF) can provide valuable information on the long-term effects of FDS intervention in terms of changes in the motor unit (MU) recruitment during gait, secondary to improved dorsiflexion.

OBJECTIVE

The aim of this study was to apply a wavelet-based TFA approach to assess the changes in neuromuscular activation of the tibialis anterior (TA), soleus (SOL), and gastrocnemius (GA) muscles after utilization of an FDS during gait post-stroke.

METHODS

Surface EMG were collected bilaterally from the TA, SOL, and GA muscles from six participants (142.9 ± 103.3 months post-stroke) while walking without the FDS at baseline and 6 months post-FDS utilization. Continuous wavelet transform was performed to get the averaged time-frequency distribution of band pass filtered (20-300 Hz) EMGs during multiple walking trials. IMNFs were computed during normalized gait and were averaged during the stance and swing phases. Percent changes in the energies associated with each frequency band of 25 Hz between 25 and 300 Hz were computed and compared between visits.

RESULTS

Averaged time-frequency representations of the affected TA, SOL, and GA EMG show altered spectral attributes post-FDS utilization during normalized gait. The mean IMNF values for the affected TA were significantly lower than the unaffected TA at baseline (p = 0.026) and follow-up (p = 0.038) during normalized stance. The mean IMNF values significantly increased (p = 0.017) for the affected GA at follow-up during normalized swing. The frequency band of 250-275 Hz significantly increased in the energies post-FDS utilization for all muscles.

CONCLUSION

The application of wavelet-based TFA of EMG and outcome measures (IMNF, energy) extracted from the time-frequency distributions suggest alterations in MU recruitment strategies after the use of FDS in individuals with chronic stroke. This further establishes the efficacy of FDS as a rehabilitation intervention that may promote motor recovery in addition to treating the secondary complications of foot drop due to post-stroke hemiplegia.

Participation and community-based walking activity after neuroprosthesis use in children with hemiplegic cerebral palsy: A pilot study1

PURPOSE

To explore the effects of neuroprosthesis use on participation, level of community-based walking activity, safety and satisfaction in children with hemiplegic CP.

METHODS

Eleven children (mean 9 years 11 months) with hemiplegic CP Gross Motor Function Classification System (GMFCS) Level I and II participated in a 16-week intervention using the Ness L300 neuroprosthesis. Outcome measures included satisfaction and performance with self-selected participation goals (Canadian Occupational Performance Measure (COPM)), level of community-based walking activity (Step Watch Activity Monitor (SAM)), trip and fall frequency (caregiver report) and a satisfaction questionnaire.

RESULTS

Significant (p< 0.001) improvements in performance and satisfaction with self-selected participation goals (COPM) were demonstrated. No significant changes were noted in SAM values. A significant (p= 0.01) decrease in trips was demonstrated from baseline to post. Satisfaction with the device was high.

CONCLUSION

Results indicate that daily neuroprosthesis use may improve performance and satisfaction with participation goals and reduce trips. No changes in community-based walking activity were noted. Further study is needed to examine response based on GMFCS levels, across geographical regions and between FES neuroprosthesis and a control group.

The effect of pressure and shear on tissue viability of human skin in relation to the development of pressure ulcers: a systematic review

Pressure ulcers are a significant problem in health care, due to high costs and large impact on patients' life. In general, pressure ulcers develop as tissue viability decreases due to prolonged mechanical loading. The relation between load and tissue viability is highly influenced by individual characteristics. It is proposed that measurements of skin blood flow regulation could provide good assessment of the risk for pressure ulcer development, as skin blood flow is essential for tissue viability. . Therefore, the aim of this systematic review is to gain insight in the relation between mechanical load and the response of the skin and underlying tissue to this loading measured in-vivo with non-invasive techniques. A systematic literature search was performed to identify articles analysing the relation between mechanical load (pressure and/or shear) and tissue viability measured in-vivo. Two independent reviewers scored the methodological quality of the 22 included studies. Methodological information as well as tissue viability parameters during load application and after load removal were extracted from the included articles and used in a meta-analysis. Pressure results in a decrease in skin blood flow parameters, compared to baseline; showing a larger decrease with higher magnitudes of load. The steepness of the decrease is mostly dependent on the anatomical location. After load removal the magnitude of the post-reactive hyperaemic peak is related to the magnitude of pressure. Lastly, shear in addition to pressure, shows an additional negative effect, but the effect is less apparent than pressure on skin viability.

A functional electrical stimulation system for human walking inspired by reflexive control principles

This study presents an innovative multichannel functional electrical stimulation gait-assist system which employs a well-established purely reflexive control algorithm, previously tested in a series of bipedal walking robots. In these robots, ground contact information was used to activate motors in the legs, generating a gait cycle similar to that of humans. Rather than developing a sophisticated closed-loop functional electrical stimulation control strategy for stepping, we have instead utilised our simple reflexive model where muscle activation is induced through transfer functions which translate sensory signals, predominantly ground contact information, into motor actions. The functionality of the functional electrical stimulation system was tested by analysis of the gait function of seven healthy volunteers during functional electrical stimulation-assisted treadmill walking compared to unassisted walking. The results demonstrated that the system was successful in synchronising muscle activation throughout the gait cycle and was able to promote functional hip and ankle movements. Overall, the study demonstrates the potential of human-inspired robotic systems in the design of assistive devices for bipedal walking.

Functional Electrical Stimulation for Foot Drop in Multiple Sclerosis: A Systematic Review and Meta-Analysis of the Effect on Gait Speed

OBJECTIVE

To review the efficacy of functional electrical stimulation (FES) used for foot drop in people with multiple sclerosis (pwMS) on gait speed in short and long walking performance tests.

DATA SOURCES

Five databases (Cochrane Library, CINAHL, Embase, MEDLINE, and PubMed) and reference lists were searched.

STUDY SELECTION

Studies of both observational and experimental design where gait speed data in pwMS could be extracted were included.

DATA EXTRACTION

Data were independently extracted and recorded. Methodologic quality was assessed using the Effective Public Health Practice Project tool.

DATA SYNTHESIS

Nineteen studies (described in 20 articles) recruiting 490 pwMS were identified and rated as moderate or weak, with none gaining a strong rating. All studies rated weak for blinding. Initial and ongoing orthotic and therapeutic effects were assessed regarding the effect of FES on gait speed in short and long walking tests. Meta-analyses of the short walk tests revealed a significant initial orthotic effect (t=2.14, P=.016), with a mean increase in gait speed of .05m/s, and ongoing orthotic effect (t=2.81, P=.003), with a mean increase of .08m/s. There were no initial or ongoing effects on gait speed in long walk tests and no therapeutic effect on gait speed in either short or long walk tests.

CONCLUSIONS

FES used for foot drop has a positive initial and ongoing effect on gait speed in short walking tests. Further fully powered randomized controlled trials comparing FES with alternative treatments are required.