Therapy of paretic arm in hemiplegic subjects augmented with a neural prosthesis: a cross-over study

Assistive technologies, including orthotic devices, for the management of contractures in adults after a stroke

BACKGROUND

Contractures (reduced range of motion and increased stiffness of a joint) are a frequent complication of stroke. Contractures can interfere with function and cause cosmetic and hygiene problems. Preventing and managing contractures might improve rehabilitation and recovery after stroke.

OBJECTIVES

To assess the effects of assistive technologies for the management of contractures in adults after a stroke.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, five other databases, and three trials registers in May 2022. We also searched for reference lists of relevant studies, contacted experts in the field, and ran forward citation searches.

SELECTION CRITERIA

Randomised controlled studies (RCTs) that used electrical, mechanical, or electromechanical devices to manage contractures in adults with stroke were eligible for inclusion in this review. We planned to include studies that compared assistive technologies against no treatment, routine therapy, or another assistive technology.

DATA COLLECTION AND ANALYSIS

Three review authors (working in pairs) selected all studies, extracted data, and assessed risk of bias. The primary outcomes were passive joint range of motion (PROM) with and without standardised force, and indirect measures of PROM. The secondary outcomes included hygiene. We also wanted to evaluate the adverse effects of assistive technology. Effects were expressed as mean differences (MDs) or standardised mean differences (SMDs) with 95% confidence intervals (CIs).

MAIN RESULTS

Seven studies fulfilled the inclusion criteria. Five of these were meta-analysed; they included 252 adults treated in acute and subacute rehabilitation settings. All studies compared assistive technology with routine therapy; one study also compared assistive technology with no treatment, but we were unable to obtain separate data for stroke participants. The assistive technologies used in the studies were electrical stimulation, splinting, positioning using a hinged board, and active repetitive motor training using a non-robotic device with electrical stimulation. Only one study applied stretching to end range. Treatment duration ranged from four to 12 weeks. The overall risk of bias was high for all studies. We are uncertain whether: • electrical stimulation to wrist extensors improves passive range of wrist extension (MD -7.30°, 95% CI -18.26° to 3.66°; 1 study, 81 participants; very low-certainty evidence); • a non-robotic device with electrical stimulation to shoulder flexors improves passive range of shoulder flexion (MD -9.00°, 95% CI -25.71° to 7.71°; 1 study; 50 participants; very low-certainty evidence); • assistive technology improves passive range of wrist extension with standardised force (SMD -0.05, 95% CI -0.39 to 0.29; four studies, 145 participants; very low-certainty evidence): • a non-robotic device with electrical stimulation to elbow extensors improves passive range of elbow extension (MD 0.41°, 95% CI -0.15° to 0.97°; 1 study, 50 participants; very low-certainty evidence). One study reported the adverse outcome of pain when using a hinged board to apply stretch to wrist and finger flexors, and another study reported skin breakdown when using a thumb splint. No studies reported hygiene or indirect measures of PROM.

AUTHORS' CONCLUSIONS

Only seven small RCTs met the eligibility criteria of this review, and all provided very low-certainty evidence. Consequently, we cannot draw firm conclusions on the effects of assistive technology compared with routine therapy or no therapy. It was also difficult to confirm whether there is a risk of harm associated with treatment using assistive technology. Future studies should apply adequate treatment intensity (i.e. magnitude and the duration of stretch) and use valid and reliable outcome measures. Such studies might better identify the role of assistive technology in the management of contractures in adults after a stroke.

Model-Based Shared Control of a Hybrid FES-Exoskeleton: An Application in Participant-Specific Robotic Rehabilitation

Hybrid exoskeleton, comprising an exoskeleton interfaced with functional electrical stimulation (FES) technique, is conceptualized to complement the weakness of each other in automated neuro-rehabilitation of sensory-motor deficits. The externally actuating exoskeleton cannot directly influence neurophysiology of the patients, while FES is difficult to use in functional or goal-oriented tasks. The latter challenge is largely inherited from the fact that the dynamics of the muscular response to FES is complex, and it is highly user- and state-dependent. Due to the retardation of the muscular contraction response to the FES profile, furthermore, a commonly used model-free control scheme, such as PID control, suffers performance. The challenge in FES control is exacerbated especially in the presence of the actuation redundancy between the volitional activity of the user, powered exoskeleton, and FES-induced muscle contractions. This study therefore presents trajectory tracking performance of the hybrid exoskeleton in a novel model-based hybrid exoskeleton scheme which entices user-specific FES model-predictive control.

Insights on the Potential Mechanisms of Action of Functional Electrical Stimulation Therapy in Combination With Task-Specific Training: A Scoping Review

OBJECTIVES

This scoping review was undertaken to synthetize and appraise the literature on the potential mechanisms of action of functional electrical stimulation therapy in combination with task-specific training (FEST + TST) in the rehabilitation following stroke, spinal cord injury, traumatic brain injury, or multiple sclerosis.

MATERIALS AND METHODS

The literature search was performed using multiple databases (including APA, PsycInfo, Medline, PubMed, EMBASE, CCRCT, and Cochrane Database of Systematic Reviews) from 1946 to June 2020. The literature search used the following terms: (spinal cord injury, paraplegia, tetraplegia, quadriplegia, stroke, multiple sclerosis, traumatic brain injury, or acquired brain injury) AND (functional electrical stimulation or FES). The search included clinical and preclinical studies without limits to language.

RESULTS

Of the 8209 titles retrieved from the primary search, 57 publications fulfilled the inclusion and exclusion criteria for this scoping review. While most publications were clinical studies (n = 50), there were only seven preclinical studies using animal models. The results of this review suggest that FEST + TST can result in multiple effects on different elements from the muscle to the cerebral cortex. However, most studies were focused on the muscle changes after FEST + TST.

CONCLUSIONS

The results of this scoping review suggest that FEST + TST can result in multiple effects on different elements of the neuromuscular system, while most research studies were focused on the muscle changes after FEST + TST. Despite the efficacy of the FEST + TST in the neurorehabilitation after CNS injury or disease, the results of this review underline an important knowledge gap with regards to the actual mechanism of action of FEST + TST.

Functional electrical stimulation therapy for restoration of motor function after spinal cord injury and stroke: a review

Functional electrical stimulation is a technique to produce functional movements after paralysis. Electrical discharges are applied to a person's muscles making them contract in a sequence that allows performing tasks such as grasping a key, holding a toothbrush, standing, and walking. The technology was developed in the sixties, during which initial clinical use started, emphasizing its potential as an assistive device. Since then, functional electrical stimulation has evolved into an important therapeutic intervention that clinicians can use to help individuals who have had a stroke or a spinal cord injury regain their ability to stand, walk, reach, and grasp. With an expected growth in the aging population, it is likely that this technology will undergo important changes to increase its efficacy as well as its widespread adoption. We present here a series of functional electrical stimulation systems to illustrate the fundamentals of the technology and its applications. Most of the concepts continue to be in use today by modern day devices. A brief description of the potential future of the technology is presented, including its integration with brain-computer interfaces and wearable (garment) technology.

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).

Validation of computerized square-drawing based evaluation of motor function in patients with stroke

Human-administered clinical scales are commonly used for quantifying motor performance and determining the course of therapy in post-stroke individuals. Computerized methods aim to improve consistency, resolution and duration of patients' evaluation. The objective of this study was to test the validity of computerized square-drawing test (DT) for assessment of shoulder and elbow function by using novel set of DT-based kinematic measures and explore their relation with Wolf Motor Function Test (WMFT) scoring. Forty-seven stroke survivors were tested before and after the rehabilitation program. DT involved drawing a square in horizontal plane using a mechanical manipulandum and a digitizing board. Depending on the initial classification of patients into low or high performance groups, the two different outcome metrics were derived from DT kinematic data for evaluation of each group. Linear regression models applied to map DT outcome values to WMFT scores for both groups resulted with high correlation coefficients and low mean absolute prediction error. In conclusion, we have identified a set of kinematic measures suitable for fast and objective motor function evaluation and functional classification, strongly correlating with WMFT score in post-stroke individuals. The results support validation of square-drawing motor function assessment, encouraging its use in clinical settings.

A Novel EMG-driven Functional Electrical Stimulator for Post- Stroke Individuals to Practice Activities of Daily Living

Prior research has demonstrated that hand function can be recovered in individuals with mild stroke through an intervention that is both 'intense' and 'functional'. However, in individuals with moderate to severe post stroke hand paresis, current evidence for an effective intervention to regain hand function is almost absent. A possible contributor to such poor recovery in these individuals may be the inability to intensively practice with the paretic hand during activities of daily living (ADLs). Many ADLs require use of the paretic arm and hand. Due to post-stroke abnormal muscle synergies, functional arm movements, such as lifting or reaching, often result in unwanted activity in the wrist/finger flexors. This makes voluntary hand opening more difficult. A possible solution to enable these individuals to practice with their paretic hand in a functional context is using devices to assist hand opening. Unfortunately, most of currently available hand rehabilitation devices do not sufficiently address hand opening with the appearance of abnormal muscle synergies. We, therefore, developed a synergy resistant, electromyographic (EMG)-driven electrical stimulation device that allows for $\mathbf {Re}$liable and $\mathbf {In}$tuitive control of the hand (ReIn-Hand) opening while using the paretic arm during lifting and reaching.

Virtual Reality Rehabilitation With Functional Electrical Stimulation Improves Upper Extremity Function in Patients With Chronic Stroke: A Pilot Randomized Controlled Study

OBJECTIVE

To compare virtual reality (VR) combined with functional electrical stimulation (FES) with cyclic FES for improving upper extremity function and health-related quality of life in patients with chronic stroke.

DESIGN

A pilot, randomized, single-blind, controlled trial.

SETTING

Stroke rehabilitation inpatient unit.

PARTICIPANTS

Participants (N=48) with hemiplegia secondary to a unilateral stroke for >3 months and with a hemiplegic wrist extensor Medical Research Council scale score ranging from 1 to 3.

INTERVENTIONS

FES was applied to the wrist extensors and finger extensors. A VR-based wearable rehabilitation device was used combined with FES and virtual activity-based training for the intervention group. The control group received cyclic FES only. Both groups completed 20 sessions over a 4-week period.

MAIN OUTCOME MEASURES

Primary outcome measures were changes in Fugl-Meyer Assessment-Upper Extremity and Wolf Motor Function Test scores. Secondary outcome measures were changes in Box and Block Test, Jebsen-Taylor Hand Function Test, and Stroke Impact Scale scores. Assessments were performed at baseline (t0) and at 2 weeks (t1), 4 weeks (t4), and 8 weeks (t8). Between-group comparisons were evaluated using a repeated-measures analysis of variance.

RESULTS

Forty-one participants were included in the analysis. Compared with FES alone, VR-FES produced a substantial increase in Fugl-Meyer Assessment-distal score (P=.011) and marginal improvement in Jebsen-Taylor Hand Function Test-gross score (P=.057). VR-FES produced greater, although nonsignificant, improvements in all other outcome measures, except in the Stroke Impact Scale-activities of daily living/instrumental activities of daily living score.

CONCLUSIONS

FES with VR-based rehabilitation may be more effective than cyclic FES in improving distal upper extremity gross motor performance poststroke.

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.

Dynamic optimization of stimulation frequency to reduce isometric muscle fatigue using a modified Hill-Huxley model

INTRODUCTION

Optimal frequency modulation during functional electrical stimulation (FES) may minimize or delay the onset of FES-induced muscle fatigue.

METHODS

An offline dynamic optimization method, constrained to a modified Hill-Huxley model, was used to determine the minimum number of pulses that would maintain a constant desired isometric contraction force.

RESULTS

Six able-bodied participants were recruited for the experiments, and their quadriceps muscles were stimulated while they sat on a leg extension machine. The force-time (F-T) integrals and peak forces after the pulse train was delivered were found to be statistically significantly greater than the force-time integrals and peak forces obtained after a constant frequency train was delivered.

DISCUSSION

Experimental results indicated that the optimized pulse trains induced lower levels of muscle fatigue compared with constant frequency pulse trains. This could have a potential advantage over current FES methods that often choose a constant frequency stimulation train. Muscle Nerve 57: 634-641, 2018.

Electrically Assisted Movement Therapy in Chronic Stroke Patients With Severe Upper Limb Paresis: A Pilot, Single-Blind, Randomized Crossover Study

OBJECTIVE

To evaluate the effects of electrically assisted movement therapy (EAMT) in which patients use functional electrical stimulation, modulated by a custom device controlled through the patient's unaffected hand, to produce or assist task-specific upper limb movements, which enables them to engage in intensive goal-oriented training.

DESIGN

Randomized, crossover, assessor-blinded, 5-week trial with follow-up at 18 weeks.

SETTING

Rehabilitation university hospital.

PARTICIPANTS

Patients with chronic, severe stroke (N=11; mean age, 47.9y) more than 6 months poststroke (mean time since event, 46.3mo).

INTERVENTIONS

Both EAMT and the control intervention (dose-matched, goal-oriented standard care) consisted of 10 sessions of 90 minutes per day, 5 sessions per week, for 2 weeks. After the first 10 sessions, group allocation was crossed over, and patients received a 1-week therapy break before receiving the new treatment.

MAIN OUTCOME MEASURES

Fugl-Meyer Motor Assessment for the Upper Extremity, Wolf Motor Function Test, spasticity, and 28-item Motor Activity Log.

RESULTS

Forty-four individuals were recruited, of whom 11 were eligible and participated. Five patients received the experimental treatment before standard care, and 6 received standard care before the experimental treatment. EAMT produced higher improvements in the Fugl-Meyer scale than standard care (P<.05). Median improvements were 6.5 Fugl-Meyer points and 1 Fugl-Meyer point after the experimental treatment and standard care, respectively. The improvement was also significant in subjective reports of quality of movement and amount of use of the affected limb during activities of daily living (P<.05).

CONCLUSIONS

EAMT produces a clinically important impairment reduction in stroke patients with chronic, severe upper limb paresis.

Evolution of Surface Motor Activation Zones in Hemiplegic Patients During 20 Sessions of FES Therapy with Multi-pad Electrodes

The purpose of this study was to examine surface motor activation zones for wrist, fingers and thumb extension movements and their temporal change during 20 therapy sessions using advanced multi-pad functional electrical stimulation system. Results from four hemiplegic patients indicate that certain zones have higher probability of eliciting each of the target movements. However, mutual overlap and variations of the zones are present not just between the subjects, but also on the intrasubject level, reflected through these session to session transformations of the selected virtual electrodes. The obtained results could be used as a priori knowledge for semi-automated optimization algorithm and could shorten the time required for calibration of the multi-pad electrode.

Restoration of Upper Limb Function in an Individual with Cervical Spondylotic Myelopathy using Functional Electrical Stimulation Therapy: A Case Study

Non-traumatic spinal cord pathology is responsible for 25–52% of all spinal cord lesions. Studies have revealed that spinal stenosis accounts for 16–21% of spinal cord injury (SCI) admissions. Impaired grips as well as slow unskilled hand and finger movements are the most common complaints in patients with spinal cord disorders, such as myelopathy secondary to cervical spondylosis. In the past, our team carried out couple of successful clinical trials, including two randomized control trials, showing that functional electrical stimulation therapy (FEST) can restore voluntary reaching and/or grasping function, in people with stroke and traumatic SCI. Motivated by this success, we decided to examine changes in the upper limb function following FEST in a patient who suffered loss of hand function due to myelopathy secondary to cervical spondylosis. The participant was a 61-year-old male who had C3–C7 posterior laminectomy and instrumented fusion for cervical myelopathy. The participant presented with progressive right hand weakness that resulted in his inability to voluntarily open and close the hand and to manipulate objects unilaterally with his right hand. The participant was enrolled in the study ~22 months following initial surgical intervention. Participant was assessed using Toronto Rehabilitation Institute’s Hand Function Test (TRI-HFT), Action Research Arm Test (ARAT), Functional Independence Measure (FIM), and Spinal Cord Independence Measure (SCIM). The pre–post differences in scores on all measures clearly demonstrated improvement in voluntary hand function following 15 1-h FEST sessions. The changes observed were meaningful and have resulted in substantial improvement in performance of activities of daily living. These results provide preliminary evidence that FEST has a potential to improve upper limb function in patients with non-traumatic SCI, such as myelopathy secondary to cervical spondylosis.

Functional electrical stimulation improves activity after stroke: a systematic review with meta-analysis

OBJECTIVE

To investigate the effect of functional electrical stimulation (FES) in improving activity and to investigate whether FES is more effective than training alone.

DATA SOURCES

Cochrane Central Register of Controlled Trials, Ovid Medline, EBSCO Cumulative Index to Nursing and Allied Health Literature, Ovid EMBASE, Physiotherapy Evidence Database (PEDro), and Occupational Therapy Systematic Evaluation of Effectiveness.

STUDY SELECTION

Randomized and controlled trials up to June 22, 2014, were included following predetermined search and selection criteria.

DATA EXTRACTION

Data extraction occurred by 2 people independently using a predetermined data collection form. Methodologic quality was assessed by 2 reviewers using the PEDro methodologic rating scale. Meta-analysis was conducted separately for the 2 research objectives.

DATA SYNTHESIS

Eighteen trials (19 comparisons) were eligible for inclusion in the review. FES had a moderate effect on activity (standardized mean difference [SMD], .40; 95% confidence interval [CI], .09-.72) compared with no or placebo intervention. FES had a moderate effect on activity (SMD, .56; 95% CI, .29-.92) compared with training alone. When subgroup analyses were performed, FES had a large effect on upper-limb activity (SMD, 0.69; 95% CI, 0.33-1.05) and a small effect on walking speed (mean difference, .08m/s; 95% CI, .02-.15) compared with control groups.

CONCLUSIONS

FES appears to moderately improve activity compared with both no intervention and training alone. These findings suggest that FES should be used in stroke rehabilitation to improve the ability to perform activities.

Volitional walking via upper limb muscle-controlled stimulation of the lumbar locomotor center in man

Gait disturbance in individuals with spinal cord lesion is attributed to the interruption of descending pathways to the spinal locomotor center, whereas neural circuits below and above the lesion maintain their functional capability. An artificial neural connection (ANC), which bridges supraspinal centers and locomotor networks in the lumbar spinal cord beyond the lesion site, may restore the functional impairment. To achieve an ANC that sends descending voluntary commands to the lumbar locomotor center and bypasses the thoracic spinal cord, upper limb muscle activity was converted to magnetic stimuli delivered noninvasively over the lumbar vertebra. Healthy participants were able to initiate and terminate walking-like behavior and to control the step cycle through an ANC controlled by volitional upper limb muscle activity. The walking-like behavior stopped just after the ANC was disconnected from the participants even when the participant continued to swing arms. Furthermore, additional simultaneous peripheral electrical stimulation to the foot via the ANC enhanced this walking-like behavior. Kinematics of the induced behaviors were identical to those observed in voluntary walking. These results demonstrate that the ANC induces volitionally controlled, walking-like behavior of the legs. This paradigm may be able to compensate for the dysfunction of descending pathways by sending commands to the preserved locomotor center at the lumbar spinal cord and may enable individuals with paraplegia to regain volitionally controlled walking.

Advances in functional electrical stimulation (FES)

This review discusses the advancements that are needed to enhance the effects of electrical stimulation for restoring or assisting movement in humans with an injury/disease of the central nervous system. A complex model of the effects of electrical stimulation of peripheral systems is presented. The model indicates that both the motor and sensory systems are activated by electrical stimulation. We propose that a hierarchical hybrid controller may be suitable for functional electrical stimulation (FES) because this type of controller acts as a structural mimetic of its biological counterpart. Specific attention is given to the neural systems at the periphery with respect to the required electrodes and stimulators. Furthermore, we note that FES with surface electrodes is preferred for the therapy, although there is a definite advantage associated with implantable technology for life-long use. The last section of the review discusses the potential need to combine FES and robotic systems to provide assistance in some cases.

Microsoft kinect-based artificial perception system for control of functional electrical stimulation assisted grasping

We present a computer vision algorithm that incorporates a heuristic model which mimics a biological control system for the estimation of control signals used in functional electrical stimulation (FES) assisted grasping. The developed processing software acquires the data from Microsoft Kinect camera and implements real-time hand tracking and object analysis. This information can be used to identify temporal synchrony and spatial synergies modalities for FES control. Therefore, the algorithm acts as artificial perception which mimics human visual perception by identifying the position and shape of the object with respect to the position of the hand in real time during the planning phase of the grasp. This artificial perception used within the heuristically developed model allows selection of the appropriate grasp and prehension. The experiments demonstrate that correct grasp modality was selected in more than 90% of tested scenarios/objects. The system is portable, and the components are low in cost and robust; hence, it can be used for the FES in clinical or even home environment. The main application of the system is envisioned for functional electrical therapy, that is, intensive exercise assisted with FES.

Functional electrical stimulation therapy for recovery of reaching and grasping in severe chronic pediatric stroke patients

Stroke affects 2.7 children per 100,000 annually, leaving many of them with lifelong residual impairments despite intensive rehabilitation. In the present study the authors evaluated the effectiveness of 48 hours of transcutaneous functional electrical stimulation therapy for retraining voluntary reaching and grasping in 4 severe chronic pediatric stroke participants. Participants were assessed using the Rehabilitation Engineering Laboratory Hand Function Test, Quality of Upper Extremity Skills Test, Pediatric Evaluation of Disability Inventory, and Assisting Hand Assessment. All participants improved on all measures. The average change scores on selected Rehabilitation Engineering Laboratory Hand Function Test components were 14.5 for object manipulation (P = .042), 0.78 Nm for instrumented cylinder (P = .068), and 14 for wooden blocks (P = .068) and on the grasp component of Quality of Upper Extremity Skills Test was 25.93 (P = .068). These results provide preliminary evidence that functional electrical stimulation therapy has the potential to improve upper limb function in severe chronic pediatric stroke patients.

Feasibility of a hybrid brain-computer interface for advanced functional electrical therapy

We present a feasibility study of a novel hybrid brain-computer interface (BCI) system for advanced functional electrical therapy (FET) of grasp. FET procedure is improved with both automated stimulation pattern selection and stimulation triggering. The proposed hybrid BCI comprises the two BCI control signals: steady-state visual evoked potentials (SSVEP) and event-related desynchronization (ERD). The sequence of the two stages, SSVEP-BCI and ERD-BCI, runs in a closed-loop architecture. The first stage, SSVEP-BCI, acts as a selector of electrical stimulation pattern that corresponds to one of the three basic types of grasp: palmar, lateral, or precision. In the second stage, ERD-BCI operates as a brain switch which activates the stimulation pattern selected in the previous stage. The system was tested in 6 healthy subjects who were all able to control the device with accuracy in a range of 0.64–0.96. The results provided the reference data needed for the planned clinical study. This novel BCI may promote further restoration of the impaired motor function by closing the loop between the “will to move” and contingent temporally synchronized sensory feedback.

Multi-pad electrode for effective grasping: design

We designed a new surface multi-pad electrode for the electrical stimulation of the forearm that is effective in controlling functional grasp in hemiplegic patients. The electrode shape and size were designed on the basis of the surface stimulation map of the forearm, determined from measurements in seven hemiplegic patients who had limited or absent voluntary movements of the fingers, thumb and wrist. The stimulation map for each patient was assessed with a conventional set of single pad Pals Platinum electrodes. Since the sites for the stimulation varied greatly between patients, the end result was a rather large multi-pad electrode. Modulating multi-pad electrode size, shape, position and individual pad stimulation parameters allows us to accommodate the diversity of the neural tissues in patients that need to be activated for functional grasp. This also allows asynchronous activation of different portions of the muscle and dynamic adaptation of the stimulation sites to appropriate underlying tissues during functional use. The validity of the determined stimulation map was tested in the same group of hemiplegic patients. The selected set of active pads resulted in fully functional and reproducible palmar and lateral grasps similar to healthy-like grasps.

Automatic determination of parameters for multipad functional electrical stimulation: application to hand opening and closing

Transcutaneous functional electrical stimulation (FES) is a method used for rehabilitation of patients having suffered a stroke or spinal cord injury. When applying FES a common problem is that stimulation electrodes have to be placed with great care in order to avoid activation of muscles close to the target muscles. A promising approach to circumvent this problem is to employ multipad FES, i.e. to employ electrode arrays containing many small electrodes allowing selective activation of muscles. In this work an algorithm is presented which automatically determines subsets of active electrodes and stimulation currents such that movements with user-specified amplitudes are induced. Using a recently developed portable multipad FES system and a virtual reality dataglove, the algorithm was tested with seven able-bodied subjects. Stimulation with parameters determined by the algorithm led to movements with a median deviation of between 0° and 5° from the specified wrist angle and between 0% and 12% from the specified degree of finger flexion.

Restoring voluntary grasping function in individuals with incomplete chronic spinal cord injury: pilot study

BACKGROUND

Functional electrical stimulation (FES) therapy has been shown to be one of the most promising approaches for improving voluntary grasping function in individuals with subacute cervical spinal cord injury (SCI).

OBJECTIVE

To determine the effectiveness of FES therapy, as compared to conventional occupational therapy (COT), in improving voluntary hand function in individuals with chronic (≥24 months post injury), incomplete (American Spinal Injury Association Impairment Scale [AIS] B-D), C4 to C7 SCI.

METHODS

Eight participants were randomized to the intervention group (FES therapy; n = 5) or the control group (COT; n = 3). Both groups received 39 hours of therapy over 13 to 16 weeks. The primary outcome measure was the Toronto Rehabilitation Institute-Hand Function Test (TRI-HFT), and the secondary outcome measures were Graded Redefined Assessment of Strength Sensibility and Prehension (GRASSP), Functional Independence Measure (FIM) self-care subscore, and Spinal Cord Independence Measure (SCIM) self-care subscore. Outcome assessments were performed at baseline, after 39 sessions of therapy, and at 6 months following the baseline assessment.

RESULTS

After 39 sessions of therapy, the intervention group improved by 5.8 points on the TRI-HFT's Object Manipulation Task, whereas the control group changed by only 1.17 points. Similarly, after 39 sessions of therapy, the intervention group improved by 4.6 points on the FIM self-care subscore, whereas the control group did not change at all.

CONCLUSION

The results of the pilot data justify a clinical trial to compare FES therapy and COT alone to improve voluntary hand function in individuals with chronic incomplete tetraplegia.

Life-like Control for Neural Prostheses: "Proximal Controls Distal"

We describe the model and implementation of the hierarchical hybrid method for controlling of the lower-arm (pronation/supination and elbow flexion/extension) in humans with disabilities. The control follows the strategy found in ablebodied humans where the movement is planned based on the task and the most distal part of the arm; yet, the command starts from the most proximal segment. The controller uses a black box of the movement and relies on temporal and spatial synergies. The driving signals are the shoulder flexion/extension velocity and acceleration, the outputs are four stimulation patterns for the control of elbow flexion/extension and pronation/supination. The operation is discrete at the voluntary and coordination levels, and continuous at the actuator level. The repertoire of movement that were considered was limited to a set of typical daily activities within the normal workspace in the sitting position only. The main application of this control is the therapeutic electrical stimulation in post-stroke hemiplegic patients.

Constraining upper limb synergies of hemiparetic patients using a robotic exoskeleton in the perspective of neuro-rehabilitation

The aim of this paper was to explore how an upper limb exoskeleton can be programmed to impose specific joint coordination patterns during rehabilitation. Based on rationale which emphasizes the importance of the quality of movement coordination in the motor relearning process, a robot controller was developed with the aim of reproducing the individual corrections imposed by a physical therapist on a hemiparetic patient during pointing movements. The approach exploits a description of the joint synergies using principal component analysis (PCA) on joint velocities. This mathematical tool is used both to characterize the patient's movements, with or without the assistance of a physical therapist, and to program the exoskeleton during active-assisted exercises. An original feature of this controller is that the hand trajectory is not imposed on the patient: only the coordination law is modified. Experiments with hemiparetic patients using this new active-assisted mode were conducted. Obtained results demonstrate that the desired inter-joint coordination was successfully enforced, without significantly modifying the trajectory of the end point.

Functional electrical therapy for hemiparesis alleviates disability and enhances neuroplasticity

Impaired motor and sensory function is common in the upper limb in humans after cerebrovascular stroke and it often remains as a permanent disability. Functional electrical stimulation therapy is known to enhance the motor function of the paretic hand; however, the mechanism of this enhancement is not known. We studied whether neural plasticity has a role in this therapy-induced enhancement of the hand motor function in 20 hemiparetic subjects with chronic stroke (age 53 ± 6 years; 7 females and 13 males; 10 with cerebral infarction and 10 with cerebral haemorrhage; and time since incident 2.4 ± 2.0 years). These subjects were randomized to functional electrical therapy or conventional physiotherapy group. Both groups received upper limb treatment (twice daily sessions) for two weeks. Behavioral hand motor function and neurophysiologic transcranial magnetic stimulation (TMS) tests were applied before and after the treatment and at 6-months follow-up. TMS is useful in assessing excitability changes in the primary motor cortex. Faster corticospinal conduction and newly found muscular responses were observed in the paretic upper limb in the functional electrical therapy group but not in the conventional therapy group after the intervention. Behaviourally, faster movement times were observed in the functional electrical therapy group but not in the conventionally treated group. Despite the small number of heterogeneous subjects, functional exercise augmented with individualized electrical therapy of the paretic upper limb may enhance neuroplasticity, observed as corticospinal facilitation, in chronic stroke subjects, along with moderate improvements in the voluntary motor control of the affected limb.

A personalized sensor-controlled microstimulator system for arm rehabilitation poststroke. Part 1: System architecture

OBJECTIVES

For rehabilitation of the poststroke upper limb in seven subjects, an external sensor-based system controls the timing of five to seven microstimulators implanted near radial nerve branches or their motor points to sequentially extend the elbow, wrist, and fingers with thumb extension and abduction, enabled at the subject's own pace. We hypothesize this system will support sequential activation of affected upper limb muscles intended to improve functional recovery.

MATERIALS AND METHODS

Presented here is a personalized sensor-controlled stimulation system, including its architecture, sensor design, and testing of equipment specific to this study, including coils and sensors.

RESULTS

All electrical and magnetic tests, and safety tests per International Electrotechnical Commission 60601-1 passed. One sensor type displayed a vulnerability to drop.

CONCLUSIONS

The new control system tested safe, met requirements, and allowed each subject to activate the system at their own pace, making the rehabilitation process more acceptable and efficient.

[Effects of functional electrical therapy on upper extremity functional motor recovery in patients after stroke--our experience and future directions]

INTRODUCTION

New neurorehabilitation together with conventional techniques provide methods and technologies for maximizing what is preserved from the sensory motor system after cerebrovascular insult. The rehabilitation technique named functional electrical therapy was investigated in more than 60 patients in acute, subacute and chronic phase after cerebrovascular insult. The functional sensory information generated by functional electrical therapy was hypothesized to result in the intensive functional brain training of the activities performed.

FUNCTIONAL ELECTRICAL THERAPY

Functional electrical therapy is a combination of functional exercise and electrical therapy. The functional electrical therapy protocol comprises voluntary movement of the paretic arm in synchrony with the electrically assisted hand functions in order to perform typical daily activities. The daily treatment of 30 minutes lasts three weeks. The outcome measures include several tests for the evaluation of arm/hand functionality: upper extremity function test, drawing test, modified Aschworth scale, motor activity log and passive range of movement.

RESULTS OF FUNCTIONAL ELECTRICAL THERAPY STUDIES

Results from our several clinical studies showed that functional electrical therapy, if applied in acute and subacute stroke patients, leads to faster and greater improvement of functioning of the hemiplegic arm/hand compared to the control group. The outcomes were significantly superior at all times after the treatment for the higher functioning group.

DISCUSSION

Additional well-planned clinical studies are needed to determine the adequate dose of treatment (timing, duration, intensity) with functional electrical therapy regarding the patient's status. A combination with other techniques should be further investigated.

Improving poststroke recovery: neuroplasticity and task-oriented training

Neurorehabilitation is a critical part of the overall process to achieve optimal outcome after stroke. Presently, the field of neurorehabilitation is in transition. New research suggesting novel approaches to optimize functional recovery after stroke is on the horizon, but clear knowledge of the underlying mechanisms of this recovery is still being unraveled. In practice, many rehabilitation centers continue to provide traditional compensatory rehabilitation training while many others are practicing newer, "task-oriented" approaches. A few centers are incorporating new technology, such as computer-based training devices or robotics, into rehabilitation care. This transition is happening because neuroscientific research has shown that neuroplastic changes in the cerebral cortex and in other parts of the central nervous system (CNS) are necessarily linked to motor skill retraining in the affected limbs. Task-oriented training that focuses on the practice of skilled motor performance is the critical link to facilitating neural reorganization and "rewiring" in the CNS. Therefore, whenever possible, task-oriented training at an intense level should be incorporated into the rehabilitation program of any patient with stroke-related motor deficits. Two such task-oriented therapies that should be available at all neurorehabilitation centers are constraint-induced movement therapy and body weight-supported treadmill training. The optimal intensity of training (frequency and duration) is still not clear but is certainly greater than that available in clinical programs. Therefore, the incorporation of automated training devices will be necessary in the future. However, the engineering necessary to make these devices effective, easy to use, affordable, and portable remains a challenge for the next decade of neurologic bioengineering research.

Interaction of electrical stimulation and voluntary hand movement in SII and the cerebellum during simulated therapeutic functional electrical stimulation in healthy adults

The therapeutic application of functional electrical stimulation (FES) has shown promising clinical results in the rehabilitation of post-stroke hemiplegia. It appears that the effect is optimal when the patterned electrical stimulation is used in close synchrony with voluntary movement, although the neural mechanisms that underlie the clinical successes reported with therapeutic FES are unknown. One possibility is that therapeutic FES takes advantage of the sensory consequences of an internal model. Here, we investigate fMRI cortical activity when FES is combined with voluntary effort (FESVOL) and we compare this activity to that produced when FES and voluntary activity (VOL) are performed alone. FESVOL revealed greater cerebellar activity compared with FES alone and reduced activity bilaterally in secondary somatosensory areas (SII) compared with VOL alone. Reduced activity was also observed for FESVOL compared with FES alone in the angular gyrus, middle frontal gyrus and inferior frontal gyrus. These findings indicate that during the VOL condition the cerebellum predicts the sensory consequences of the movement and this reduces the subsequent activation in SII. The decreased SII activity may reflect a better match between the internal model and the actual sensory feedback. The greater cerebellar activity coupled with reduced angular gyrus activity in FESVOL compared with FES suggests that the cortex may interpret sensory information during the FES condition as an error-like signal due to the lack of a voluntary component in the movement.

Advances in the use of electrical stimulation for the recovery of motor function

This chapter sheds light on several issues that are being explored to optimize the application of electrical stimulation in a motor neural prosthesis (MNP) for the restoration of movement in humans with paralysis. Although several MNPs are commercially available, there are issues that limit their use in therapy and/or daily assistance: (1) the users' intention of what and how to move needs to be effectively transmitted to the MNP controller; (2) interface to the neural pathways that leads to physiological-like activation should be improved; (3) artificial control of the MNP should match the biological control of the preserved biological systems; and (4) sensors information should be fused and provided to both the controller of the MNP and the user. We suggest that with the improved use of cortical or other physiological signals, application of multipad electrodes with special protocols, rule-based control that mimics biological control, and with the incorporation of micro- and nanotechnologies, wireless communications, and microcontrollers, the MNP operation can be greatly enhanced. The chapter specifically addresses the control of MNP for the upper extremities and provides details on the new surface multipad electrodes that are of interest for neurorehabilitation of stroke patients.

Review of electrical stimulation in cerebral palsy and recommendations for future directions

Electrical stimulation (ES) for treatment of neuromuscular disorders is introduced. Various forms of ES are defined. Characteristics of cerebral palsy (CP) and treatment options are given. The clinical objectives of ES for CP treatment are stated. A review of the literature for treatment in CP is given. Several common themes within the literature and limitations in prior studies are explored. The majority of studies have used surface stimulation, which has several inherent limitations. To address these limitations, implanted devices may be used. Implanted device systems include percutaneous stimulation systems, and fully implantable leaded systems. While both of these technologies have advantages over surface stimulation, they also have their own limitations. To further address the limitations of percutaneous and fully implantable leaded systems, the Alfred Mann Foundation has developed a completely implantable, telemetered device known as the Radio Frequency Microstimulator (RFM). Results from a study using the RFM for arm rehabilitation in poststroke patients are given. A list of desirable design features for an ES system for CP is given. The next generation microstimulator device under development at the Alfred Mann Foundation is presented. This device may well serve the needs for ES in CP.

Motor training of upper extremity with functional electrical stimulation in early stroke rehabilitation

BACKGROUND

Functional electrical stimulation (FES) allows active exercises in stroke patients with upper extremity paralysis.

OBJECTIVE

To investigate the effect of motor training with FES on motor recovery in acute and subacute stroke patients with severe to complete arm and/or hand paralysis.

METHODS

For this pilot study, 23 acute and subacute stroke patients were randomly assigned to the intervention (n = 12) and control group (n = 11). Distributed over 4 weeks, FES training replaced 12 conventional training sessions in the intervention group. An Extended Barthel Index (EBI) subscore assessed the performance of activities of daily living (ADL). The Chedoke McMaster Stroke Assessment (CMSA) measured hand and arm function and shoulder pain. The Modified Ashworth Scale (MAS) assessed resistance to passive movement. Unblinded assessments were performed prior to and following the end of the training period.

RESULTS

The EBI subscore and CMSA arm score improved significantly in both groups. The CMSA hand function improved significantly in the FES group. Resistance to passive movement of finger and wrist flexors increased significantly in the FES group. Shoulder pain did not change significantly. None of the outcome measures, however, demonstrated significant gain differences between the groups.

CONCLUSIONS

We did not find clear evidence for superiority or inferiority of FES. Our findings, and those of similar trials, suggest that the number of sessions should be at least doubled to test for superiority of FES in these highly impaired patients and approximately 50 participants would have to be assigned to each therapeutic intervention to find significant differences.

Intramuscular Electrical Stimulation for Upper Limb Recovery in Chronic Hemiparesis: An Exploratory Randomized Clinical Trial

Background. Surface electrical stimulation (ES) has been shown to improve the motor impairment of stroke survivors. However, surface ES can be painful and motor activation can be inconsistent from session to session. Percutaneous intramuscular ES may be an effective alternative. Objective. Evaluate the effectiveness of percutaneous intramuscular ES in facilitating the recovery of the hemiparetic upper limb of chronic stroke survivors. Methods. A total of 26 chronic stroke survivors were randomly assigned to percutaneous intramuscular ES for hand opening (n = 13) or percutaneous ES for sensory stimulation only (n = 13). The intramuscular ES group received cyclic, electromyography (EMG)-triggered or EMG-controlled ES depending on baseline motor status. All participants received 1 hour of stimulation per day for 6 weeks. After completion of ES, participants received 18 hours of task-specific functional training. The primary outcome measure was the Fugl-Meyer Motor Assessment. Secondary measures included the Arm Motor Ability Test and delay and termination of EMG activity. Outcomes were assessed in a blinded manner at baseline, at the end of ES, at the end of functional training, and at 1, 3, and 6 months follow-up. Results. Repeated measure analysis of variance did not yield any significant treatment, or time by treatment interaction effects for any of the outcome measures. Conclusion. Percutaneous intramuscular ES does not appear to be any more effective than sensory ES in enhancing the recovery of the hemiparetic upper limb among chronic stroke survivors. However, because of the exploratory nature of the study and its inherent limitations, conclusions must be drawn with caution.

Neuromuscular electrical stimulation for motor restoration in hemiplegia

Clinical applications of neuromuscular electrical stimulation (NMES) in stroke rehabilitation provide both therapeutic and functional benefits. Therapeutic applications include upper and lower limb motor relearning and reduction of poststroke shoulder pain. There is growing evidence that NMES, especially those approaches that incorporate task-specific strategies, is effective in facilitating upper and lower limb motor relearning. There is also strong evidence that NMES reduces poststroke shoulder subluxation and pain. Functional applications include upper and lower limb neuroprostheses. Lower limb neuroprostheses in the form of peroneal nerve stimulators is effective in enhancing the gait speed of stroke survivors with foot-drop. The development of hand neuroprostheses is in its infancy and must await additional fundamental and technical advances before reaching clinical viability. The limitations of available systems and future developments are discussed.

Automatic determination of the optimal shape of a surface electrode: selective stimulation

We present a method for automatic determination of the shape and position of the surface electrode for selective control of fingers extension and flexion by means of electrical stimulation. The multi-pad electrodes used in the experiments comprised 24 pads (1cm diameter) distributed over an area (7 cm x 10 cm) positioned over dorsal and volar aspects of the forearm. The four-channel stimulation system for grasping comprised also an oval reference electrode over the carpal tunnel, and two oval electrodes over the thenar and thumb extensor muscles. We measured seven angles: proximal inter-phalangeal and metacarpal phalangeal index and ring finger joint rotations, wrist extension/flexion and ulnar/radial rotation, and pronation/supination of the forearm. The optimal electrode was determined as the combination of pads that led to fingers, wrist and forearm rotations being similar to the trajectories of healthy individuals when grasping. The similarity of trajectories was assessed by analyzing the aggregate error defined as the sum of squares of differences between the angles measured when stimulating the forearm in tetraplegics and the angles measured in healthy individuals. The aggregate errors were determined from measurements during sequential stimulation of each of the 24 pads. The analysis comprised hand opening and closing for palmar and lateral grasps. The time for determining the optimal electrode was about 10 min. The optimal electrodes had different branched shapes in each of the six tetraplegics; however, once determined they remained unchanged when tested on different days.