Whole-body vibration may not affect bone mineral density and bone turnover in persons with chronic spinal cord injury: A preliminary study.

CONTEXT: Spinal-cord injury (SCI) induces bone loss and dramatically increases the risk of fracture. OBJECTIVES: Determine the effects of whole-body vibration (WBV) on areal bone mineral density (aBMD), whole body composition and bone biological parameters in individuals with chronic-state SCI. DESIGN: Randomized study. SETTING: Centre Neurologique PROPARA. PARTICIPANTS: Fourteen subjects were randomly assigned to a WBV or a control group. INTERVENTIONS: WBV (20-45 min, 30-45 Hz, 0.5 g) was performed in verticalized persons twice weekly for 6 months. OUTCOME MEASURES: aBMD was measured by DXA at baseline and 6 months and bone biological parameters at baseline, 1, 3 and 6 months. RESULTS: No significant aBMD change was found in either the WBV or control group after 6 months of follow-up. Similarly, periostin, sclerostin and bone turnover markers remained relatively stable throughout follow-up and no difference in variation was observed within-group and between groups. Except for whole-body fat mass, which showed a significant decrease in the WBV group compared to controls, no difference in changes was observed, whatever the localization for fat and lean body mass. CONCLUSIONS: During the chronic phase, aBMD and bone remodeling reach a new steady state. However, the DXA technique and the bone markers, including sclerostin and periostin, both of which reflect bone cell activity influenced by mechanical strain, showed that the bone tissue of individuals with SCI was insensitive to 6 months of WBV training at the study dose. Nevertheless, results of this preliminary study that was underpowered need to be confirmed and other modalities of WBV may be more effective in improving aBMD of this population. TRIALS REGISTRATION: N°IDRCB:2011-A00224-37.

Alteration of Volumetric Bone Mineral Density Parameters in Men with Spinal Cord Injury.

Spinal cord injury (SCI) induces severe losses of trabecular and cortical volumetric bone mineral density (vBMD), which cannot be discriminated with conventional dual-energy X-ray absorptiometry (DXA) analysis. The objectives were to: (i) determine the effects of SCI on areal BMD (aBMD) and vBMD determined by advanced 3D-DXA-based methods at various femoral regions and (ii) model the profiles of 3D-DXA-derived parameters with the time since injury. Eighty adult males with SCI and 25 age-matched able-bodied (AB) controls were enrolled in this study. Trabecular and cortical vBMD, cortical thickness and derived strength parameters were assessed by 3D-SHAPER® software at various femoral subregions. Individuals with SCI had significantly lower integral vBMD, trabecular vBMD, cortical vBMD, cortical thickness and derived bone strength parameters (p < 0.001 for all) in total proximal femur compared with AB controls. These alterations were approximately to the same degree for all three femoral subregions, and the difference between the two groups tended to be greater for cortical vBMD than trabecular vBMD. There were minor differences according to the lesion level (paraplegics vs tetraplegics) for all 3D-DXA-derived parameters. For total proximal femur, the decreasing bone parameters tended to reach a new steady state after 5.1 years for integral vBMD, 7.4 years for trabecular vBMD and 9.2 years for cortical vBMD following SCI. At proximal femur, lower vBMD (integral, cortical and trabecular) and cortical thickness resulted in low estimated bone strength in individuals with SCI. It remains to be demonstrated whether these new parameters are more closely associated with fragility fracture than aBMD.

Activating effective functional hand movements in individuals with complete tetraplegia through neural stimulation.

Individuals with complete cervical spinal cord injury suffer from a permanent paralysis of upper limbs which prevents them from achieving most of the activities of daily living. We developed a neuroprosthetic solution to restore hand motor function. Electrical stimulation of the radial and median nerves by means of two epineural electrodes enabled functional movements of paralyzed hands. We demonstrated in two participants with complete tetraplegia that selective stimulation of nerve fascicles by means of optimized spreading of the current over the active contacts of the multicontact epineural electrodes induced functional and powerful grasping movements which remained stable over the 28 days of implantation. We also showed that participants were able to trigger the activation of movements of their paralyzed limb using an intuitive interface controlled by voluntary actions and that they were able to perform useful functional movements such as holding a can and drinking through a straw.

Influence of the H-reflex on the selectivity of recruitment using multi-contact epineural stimulation of the median nerve in a participant with complete tetraplegia.

Multi-contact epineural electrical stimulation is a technique that can be used to restore grip movements in people with complete tetraplegia. However, neural stimulation can induce undesired H-reflex. This reflex is known to induce a global lower recruitment threshold together with a steepest recruitment curve leading to a degraded selective response. In this study, during stimulation of the median nerve using a multi-contact cuff electrode, a H-reflex response was observed for one muscle (the pronator teres i.e. PT) among the five recorded. As both M-wave and H-wave were separately recorded, we compared the changes of recruitment, recruitment order and se-lectivity with and without the H-reflex and found that blocking the reflex would have enhance the selectivity and increase the range of the intensity amplitude while providing a higher level of gripping force. Thus, blocking H-reflex is an important issue to further enhance epineural multicontact selective stimulation.

OIDA: An optimal interval detection algorithm for automatized determination of stimulation patterns for FES-Cycling in individuals with SCI.

BACKGROUND: FES-Cycling is an exciting recreational activity, which allows certain individuals after spinal cord injury or stroke to exercise their paralyzed muscles. The key for a successful application is to activate the right muscles at the right time. METHODS: While a stimulation pattern is usually determined empirically, we propose an approach using the torque feedback provided by a commercially available crank power-meter installed on a standard trike modified for FES-Cycling. By analysing the difference between active (with stimulation) and passive (without stimulation) torques along a full pedalling cycle, it is possible to differentiate between contributing and resisting phases for a particular muscle group. In this article we present an algorithm for the detection of optimal stimulation intervals and demonstrate its functionality, bilaterally for the quadriceps and hamstring muscles, in one subject with complete SCI on a home trainer. Stimulation patterns were automatically determined for two sensor input modalities: the crank-angle and a normalized thigh-angle (i.e. cycling phase, measured via inertial measurement units). In contrast to previous studies detecting automatic stimulation intervals on motorised ergo-cycles, our approach does not rely on a constant angular velocity provided by a motor, thus being applicable to the domain of mobile FES-Cycling. RESULTS: The algorithm was successfully able to identify stimulation intervals, individually for the subject's left and right quadriceps and hamstring muscles. Smooth cycling was achieved without further adaptation, for both input signals (i.e. crank-angle and normalized thigh-angle). CONCLUSION: The automatic determination of stimulation patterns, on basis of the positive net-torque generated during electrical stimulation, can help to reduce the duration of the initial fitting phase and to improve the quality of pedalling during a FES-Cycling session. In contrast to previous works, the presented algorithm does not rely on a constant angular velocity and thus can be effectively implemented into mobile FES-Cycling systems. As each muscle or muscle group is assessed individually, our algorithm can be used to evaluate the efficiency of novel electrode configurations and thus could promote increased performances during FES-Cycling.

Frequency-Domain sEMG Classification Using a Single Sensor.

Working towards the development of robust motion recognition systems for assistive technology control, the widespread approach has been to use a plethora of, often times, multi-modal sensors. In this paper, we develop single-sensor motion recognition systems. Utilising the peripheral nature of surface electromyography (sEMG) data acquisition, we optimise the information extracted from sEMG sensors. This allows the reduction in sEMG sensors or provision of contingencies in a system with redundancies. In particular, we process the sEMG readings captured at the trapezius descendens and platysma muscles. We demonstrate that sEMG readings captured at one muscle contain distinct information on movements or contractions of other agonists. We used the trapezius and platysma muscle sEMG data captured in able-bodied participants and participants with tetraplegia to classify shoulder movements and platysma contractions using white-box supervised learning algorithms. Using the trapezius sensor, shoulder raise is classified with an accuracy of 99%. Implementing subject-specific multi-class classification, shoulder raise, shoulder forward and shoulder backward are classified with a 94% accuracy amongst object raise and shoulder raise-and-hold data in able bodied adults. A three-way classification of the platysma sensor data captured with participants with tetraplegia achieves a 95% accuracy on platysma contraction and shoulder raise detection.

A Residual Movement Classification Based User Interface for Control of Assistive Devices by Persons With Complete Tetraplegia.

OBJECTIVE: Complete tetraplegia can deprive a person of hand function. Assistive technologies may improve autonomy but needs for ergonomic interfaces for the user to pilot these devices still persist. Despite the paralysis of their arms, people with tetraplegia may retain residual shoulder movements. In this work we explored these movements as a mean to control assistive devices. METHODS: We captured shoulder movement with a single inertial sensor and, by training a support vector machine based classifier, we decode such information into user intent. RESULTS: The setup and training process take only a few minutes and so the classifiers can be user specific. We tested the algorithm with 10 able body and 2 spinal cord injury participants. The average classification accuracy was 80% and 84%, respectively. CONCLUSION: The proposed algorithm is easy to set up, its operation is fully automated, and achieved results are on par with state-of-the-art systems. SIGNIFICANCE: Assistive devices for persons without hand function present limitations in their user interfaces. Our work presents a novel method to overcome some of these limitations by classifying user movement and decoding it into user intent, all with simple setup and training and no need for manual tuning. We demonstrate its feasibility with experiments with end users, including persons with complete tetraplegia without hand function.

Restoring Hand Functions in People with Tetraplegia through Multi-Contact, Fascicular, and Auto-Pilot Stimulation: A Proof-of-Concept Demonstration.

Two multi-contact epineural electrodes were placed around radial and median nerves of two subjects with high tetraplegia C4, American Spinal Injury Association Impairment Scale (AIS) A, group 0 of the International Classification for Surgery of the Hand in Tetraplegia. The purpose was to study the safety and capability of these electrodes to generate synergistic motor activation and functional movements and to test control interfaces that allow subjects to trigger pre-programmed stimulation sequences. The device consists of a pair of neural cuff electrodes and percutaneous cables with two extracorporeal connection cables inserted during a surgical procedure and maintained for 28 days. Continuity tests of the electrodes, selectivity of movements induced, motor capacities for grasping and gripping, conformity of the control order, tolerance, and acceptability were assessed. Neither of the two participants showed general and local comorbidity. Acceptability was optimal. None of the stimulation configurations generated contradictory movements. The success rate in task execution by the electro-stimulated hand exceeded the target of 50% (54% and 51% for patients 1 and 2, respectively). The compliance rate of the control orders in both patients was >90% using motion inertial measurement unit (IMU)-based detection and 100% using electromyography (EMG)-based detection in patient 1. These results support the relevance of neural stimulation of the tetraplegic upper limb with a more selective approach, using multi-contact epineural electrodes with nine and six contact points for the median and radial nerve respectively.

Perspectives on usability and accessibility of an autonomous humanoid robot living with elderly people.

PURPOSE: The aim of this study was to assess how cohabitation with a social robot for seven days night and day is perceived by elderly potential users and to suggest technological improvements for future home integration. METHODS: Fifteen participants were invited to interact with Pepper®, 24 h a day and 7 days a week. Perceived utility assessment was achieved using a dedicated questionnaire. Usability assessment was carried out by measuring satisfaction with the human-robot interaction and listing malfunctions. RESULTS: Seventy-eight tasks out of 115 tasks were reported respectively as very high and high. On day 1, satisfaction was at its higher level with a mean of 6.8. On day 8, it maintained at 6.0 despite technical malfunctions and failures, listed with details in this paper. Acceptability was positive. Pepper was mainly considered as an assistant and a link with family and friends and never as an enemy or intruder. Pepper has proven to be potentially able to meet five needs: making the person's environment safe by alerting contact persons, reminding the user of health-related tasks, enabling "doubt removal", maintaining social relationships and following the user. CONCLUSIONS: Pepper is more than a "demonstration" device classified as level 6 of the nine-point Technology Readiness Level (TRL) scale for the hard and software and level 5 in behavioural terms. Once the technological locks and malfunctions have been overcome, Pepper should be applicable in the home, allowing users to test it in a more familiar environment.Implications for RehabilitationPepper, a humanoid robot, has been perceived as rich in potentialities that can help and secure a fragile person.Following this experience of cohabitation with a humanoid robot, the participants were unanimous in thinking that assistive robotics is the future.To be useful, the robot's people tracking function must inevitably be improved.Pepper, the first humanoid robot ever marketed, is more than just a "demonstration"device, classified at level 6 of Technological Readiness Levels (TRL) for supporting hardware and software and level 5 in terms of behavior.

Sacral Anterior Root Stimulation and Visceral Function Outcomes in Spinal Cord Injury-A Systematic Review of the Literature Over Four Decades.

OBJECTIVE: Sacral anterior root stimulation (SARS) was developed 40 years ago to restore urinary and bowel functions to individuals with spinal cord injury. Mostly used to restore lower urinary tract function, SARS implantation is coupled with sacral deafferentation to counteract the problems of chronic detrusor sphincter dyssynergia and detrusor overactivity. In this article, we systematically review 40 years of SARS implantation and assess the medical added value of this approach in accordance with the PRISMA guidelines. We identified 4 axes of investigation: 1) impact on visceral functions, 2) implantation safety and device reliability, 3) individuals' quality of life, and 4) additional information about the procedure. METHODS: A systematic review was performed. Three databases were consulted: PubMed, EBSCOhost, and Pascal. A total of 219 abstracts were screened and 38 articles were retained for analysis (1147 implantations). RESULTS: The SARS technique showed good clinical results (85.9% of individuals used their implant for micturition and 67.9% to ease bowel movements) and improved individual quality of life. Conversely, several sources of complications were reported after implantation (e.g., surgical complications and failure). CONCLUSIONS: Despite promising results, a decline in implantations was observed. This decline can be linked to the complication rate, as well as to the development of new therapeutics (e.g., botulinum toxin) and directions for research (spinal cord stimulation) that may have an impact on people. Nevertheless, the lack of alternatives in the short-term suggests that the SARS implant is still relevant for the restoration of visceral functions after spinal cord injury.

Weight-bearing shoulder and rotator cuff tear.

Two percent of the general population are wheelchair-dependent. The shoulder takes on the weight-bearing locomotor function, and tends with age to develop degenerative pathologies, notably in the rotator cuff. The association between weight-bearing shoulder and rotator cuff tear raises several questions: what are the mechanisms by which wheelchair propulsion and transfer overload the shoulder, and what specificities do the lesions display? They occur in younger patients than in the rest of the population, after about 15 years' fairly constant wheelchair use. As well as the classical supraspinatus damage, an anterior cuff extension is the most frequent case. Is there a particular clinical presentation of cuff tear in this population? As the shoulder cannot be functionally protected, pain is constant and asymptomatic cuff tear is rare. Any pain after 12 years' wheelchair use requires morphologic exploration. How does treatment strategy differ for the weight-bearing shoulder? More than the classic quest for compensation, in the weight-bearing shoulder, the rotator cuff should be protected against any local aggression by systematic surgical recalibration of the subacromial space, and all lesions should be repaired, to avoid extension. Are functional results to be expected to be poorer in this population? On condition that the suture is protected by postponing any transfer beyond 4 months and that the shoulder is protected on a daily basis, analytic results and healing rates are comparable to those in the general population. However, general complications and skin complications are more frequent and require postoperative care in a specialized center.

Benefits of 1-Yr Home Training With Functional Electrical Stimulation Cycling in Paraplegia During COVID-19 Crisis.

ABSTRACT: The purpose of this observational study was to report the experience of a 1-yr home training with functional electrical stimulation cycling of a person with T4 American Impairment Scale A paraplegia for 9 yrs, homebound due to the COVID-19 health crisis. The 40-yr-old participant had a three-phase training: V1, isometric stimulation; V2, functional electrical stimulation cycling for 3 sessions/wk; and V3, functional electrical stimulation cycling for 2-4 sessions/wk. Data on general and physical tolerance, health impact, and performance were collected. Borg Scale score relating to fatigue was 10.1 before training and 11.8 after training. The average score for satisfaction at the end of sessions was 8.7. Lean leg mass increased more than 29%, although total bone mineral density dropped by 1.6%. The ventilatory thresholds increased from 19.5 to 29% and the maximum ventilatory peak increased by 9.5%. Rosenberg's Self-esteem Scale score returned to its highest level by the end of training. For the only track event on a competition bike, the pilot covered a distance of 1607.8 m in 17 mins 49 secs. When functional electrical stimulation cycling training is based on a clear and structured protocol, it offers the person with paraplegia the opportunity to practice this activity recreationally and athletically. In times of crisis, this training has proven to be very relevant.

A Novel Framework for Quantifying Accuracy and Precision of Event Detection Algorithms in FES-Cycling.

Functional electrical stimulation (FES) is a technique used in rehabilitation, allowing the recreation or facilitation of a movement or function, by electrically inducing the activation of targeted muscles. FES during cycling often uses activation patterns which are based on the crank angle of the pedals. Dynamic changes in their underlying predefined geometrical models (e.g., change in seating position) can lead to desynchronised contractions. Adaptive algorithms with a real-time interpretation of anatomical segments can avoid this and open new possibilities for the automatic design of stimulation patterns. However, their ability to accurately and precisely detect stimulation triggering events has to be evaluated in order to ensure their adaptability to real-case applications in various conditions. In this study, three algorithms (Hilbert, BSgonio, and Gait Cycle Index (GCI) Observer) were evaluated on passive cycling inertial data of six participants with spinal cord injury (SCI). For standardised comparison, a linear phase reference baseline was used to define target events (i.e., 10%, 40%, 60%, and 90% of the cycle's progress). Limits of agreement (LoA) of ±10% of the cycle's duration and Lin's concordance correlation coefficient (CCC) were used to evaluate the accuracy and precision of the algorithm's event detections. The delays in the detection were determined for each algorithm over 780 events. Analysis showed that the Hilbert and BSgonio algorithms validated the selected criteria (LoA: +5.17/-6.34% and +2.25/-2.51%, respectively), while the GCI Observer did not (LoA: +8.59/-27.89%). When evaluating control algorithms, it is paramount to define appropriate criteria in the context of the targeted practical application. To this end, normalising delays in event detection to the cycle's duration enables the use of a criterion that stays invariable to changes in cadence. Lin's CCC, comparing both linear correlation and strength of agreement between methods, also provides a reliable way of confirming comparisons between new control methods and an existing reference.

A Sensor-Based Multichannel FES System to Control Knee Joint and Reduce Stance Phase Asymmetry in Post-Stroke Gait.

Most of the studies using functional electrical stimulation (FES) in gait rehabilitation have been focused on correcting the drop foot syndrome. Using FES to control the knee joint in individuals with central nervous system (CNS) disorders could also play a key role in gait recovery: spasticity decrease, higher range of motion, positive effect on balance, limiting hyperextension and flexion in stance phase, reducing joint overload, etc. In stance phase, an accurate timing and a fine tuning of stimulation parameters are however required to provide a proper control of the knee stimulation while ensuring a safe and efficient support. In this study, 11 participants were equipped with inertial measurements units (IMU) and foot pressure insoles after supratentorial ischemic or hemorrhagic stroke, informing on knee angle and gait events used to online adapt FES during a 10 m walking protocol. Asymmetry of stance time and weight bearing were monitored as well as gait quality and physiological cost through a series of relevant markers. Vertical trunk motion has been significantly reduced during gait with FES (p-value = 0.038). Despite no significant improvement of stance phase asymmetry has been found, this preliminary work shows evidence of promising technical and rehabilitative potentials of a sensor-based multichannel FES system to control knee joint in post-stroke gait.

Standardizing fatigue-resistance testing during electrical stimulation of paralysed human quadriceps muscles, a practical approach.

BACKGROUND: Rapid onset of muscular fatigue is still one of the main issues of functional electrical stimulation (FES). A promising technique, known as distributed stimulation, aims to activate sub-units of a muscle at a lower stimulation frequency to increase fatigue-resistance. Besides a general agreement on the beneficial effects, the great heterogeneity of evaluation techniques, raises the demand for a standardized method to better reflect the requirements of a practical application. METHODS: This study investigated the fatigue-development of 6 paralysed quadriceps muscles over the course of 180 dynamic contractions, evaluating different electrode-configurations (conventional and distributed stimulation). For a standardized comparison, fatigue-testing was performed at 40% of the peak-torque during a maximal evoked contraction (MEC). Further, we assessed the isometric torque for each electrode-configuration at different knee-extension-angles (70°-170°, 10° steps). RESULTS: Our results showed no significant difference in the fatigue-index for any of the tested electrode-configurations, compared to conventional-stimulation. We conjecture that the positive effects of distributed stimulation become less pronounced at higher stimulation amplitudes. The isometric torque produced at different knee-extension angles was similar for most electrode-configurations. Maximal torque-production was found at 130°-140° knee-extension-angle, which correlates with the maximal knee-flexion-angles during running. CONCLUSION: In most practical applications, FES is intended to initiate dynamic movements. Therefore, it is crucial to assess fatigue-resistance by using dynamic contractions. Reporting the relationship between produced torque and knee-extension-angle can help to observe the stability of a chosen electrode-configuration for a targeted range-of-motion. Additionally, we suggest to perform fatigue testing at higher forces (e.g. 40% of the maximal evoked torque) in pre-trained subjects with SCI to better reflect the practical demands of FES-applications.

Selective neural electrical stimulation restores hand and forearm movements in individuals with complete tetraplegia.

BACKGROUND: We hypothesized that a selective neural electrical stimulation of radial and median nerves enables the activation of functional movements in the paralyzed hand of individuals with tetraplegia. Compared to previous approaches for which up to 12 muscles were targeted through individual muscular stimulations, we focused on minimizing the number of implanted electrodes however providing almost all the needed and useful hand movements for subjects with complete tetraplegia. METHODS: We performed acute experiments during scheduled surgeries of the upper limb with eligible subjects. We scanned a set of multicontact neural stimulation cuff electrode configurations, pre-computed through modeling simulations. We reported the obtained isolated and functional movements that were considered useful for the subject (different grasping movements). RESULTS: In eight subjects, we demonstrated that selective stimulation based on multicontact cuff electrodes and optimized current spreading over the active contacts provided isolated, compound, functional and strong movements; most importantly 3 out of 4 had isolated fingers or thumb flexion, one patient performed a Key Grip, another one the Power and Hook Grips, and the 2 last all the 3 Grips. Several configurations were needed to target different areas within the nerve to obtain all the envisioned movements. We further confirmed that the upper limb nerves have muscle specific fascicles, which makes it possible to activate isolated movements. CONCLUSIONS: The future goal is to provide patients with functional restoration of object grasping and releasing with a minimally invasive solution: only two cuff electrodes above the elbow. Ethics Committee / ANSM clearance prior to the beginning of the study (inclusion period 2016-2018): CPP Sud Méditerranée, #ID-RCB:2014-A01752-45, first acceptance 10th of February 2015, amended 12th of January 2016. TRIAL REGISTRATION: (www.clinicaltrials.gov): #NCT03721861, Retrospectively registered on 26th of October 2018.

Responsiveness of the Motor Capacities Scale to upper limb reconstructive surgery in persons with tetraplegia due to cervical spinal cord injury.

STUDY DESIGN: Psychometric Study. OBJECTIVES: To assess responsiveness of the Motor Capacities Scale (MCS) in people with tetraplegia who have undergone upper limb reconstructive surgery. SETTINGS: Rehabilitation clinics in France. METHODS: The MCS is an arm/hand function test with 31 basic tasks, subdivided into four sub-categories (MCS A, MCS B, MCS C, and MCS D). Data were recorded preoperatively and following full completion of the surgical program. The Functional Independence Measure (FIM) and a ten-point numeric scale related to patients' satisfaction with the overall surgical result were included. Data were analyzed using responsiveness measures-the effect size (ES), the standardized response mean (SRM), and the minimal clinically important difference (MCID). RESULTS: Twenty-seven participants were included. Fourteen patients underwent unilateral surgery and 13 bilateral surgery. ES and SRM were moderate or good (ES/SRM of MCS B = 0.76/0.81, ES/SRM MCS C = 0.68/0.77, and ES/SRM MCS D = 0.77/0.88). For MCS A and FIM, both SRM and ES showed a small degree of responsiveness. For the MCS total score, the ES value indicated a moderate degree of responsiveness while SRM was excellent. Total MCS score, MCS C subscore and MCS D subscore showed significantly higher ES values in the "bilateral surgery" group than in the "unilateral group". The estimation of MCIDs showed low threshold values of MCS scores changes (total score and subscores) beyond which the satisfaction rate is >6. CONCLUSIONS: This study provides evidence of acceptable responsiveness of the MCS to changes using the SRM following upper limb reconstruction in patients with tetraplegia.

Wireless Electrical Stimulators and Sensors Network for Closed Loop Control in Rehabilitation.

This paper presents a wireless distributed Functional Electrical Stimulation (FES) architecture. It is based on a set of, potentially heterogeneous, distributed stimulation and measurement units managed by a wearable controller. Through a proof-of-concept application, the characterization of the wireless network performances was assessed to check the adequacy of this solution with open-loop and closed-loop control requirements. We show the guaranteed time performances over the network through the control of quadriceps and hamstrings stimulation parameters based on the monitoring of the knee joint angle. Our solution intends to be a tool for researchers and therapists to develop closed-loop control algorithms and strategies for rehabilitation, allowing the design of wearable systems for a daily use context.

Training with FES-assisted cycling in a subject with spinal cord injury: Psychological, physical and physiological considerations.

CONTEXT: People with spinal cord injury (SCI) experience the effects of a sedentary lifestyle very early on. Literature data suggest that programs using FES-assisted cycling would contribute to reduce the consequences of physical inactivity. The objective was to assess the feasibility of 12-month training on a FES-assisted bike of a subject with paraplegia for 21 years, T3, Asia Impairment Scale (AIS) A. An evaluation of morbidity, self-esteem, satisfaction, quality of life and duration of pedaling was performed. The impact on pain, cardiorespiratory function, body composition and bone metabolism were also assessed. FINDINGS: The acceptability score of the training constraints increased from 51 to 59/65 and satisfaction was high around 8/10. The pedaling duration increased from 1' to 26' on the recumbent bike and from 1' to 15' on open terrain. No significant changes were found with BMD and cardiorespiratory measures during exercise tests. SF 36 showed significant improvement of more than 10% and the Rosenberg Self Esteem score rapidly improved from 36 to 39/40. At the end of the training, the patient reached the objective of the Cybathlon 2016 by covering 750 m in less than 8 minutes, at an average speed of 5.80 km/hr. CONCLUSION/CLINICAL RELEVANCE: A person with high and complete level of SCI for more than 20 years can undertake this type of challenge if the prerequisites are met; this training is without danger if the safety precautions are respected; the challenge of participating in a competition had a powerful impact on JP's self-esteem and perceived quality of life.

FES-Induced Cycling in Complete SCI: A Simpler Control Method Based on Inertial Sensors.

This article introduces a novel approach for a functional electrical stimulation (FES) controller intended for FES-induced cycling based on inertial measurement units (IMUs). This study aims at simplifying the design of electrical stimulation timing patterns while providing a method that can be adapted to different users and devices. In most of studies and commercial devices, the crank angle is used as an input to trigger stimulation onset. We propose instead to use thigh inclination as the reference information to build stimulation timing patterns. The tilting angles of both thighs are estimated from one inertial sensor located above each knee. An IF-THEN rule algorithm detects, online and automatically, the thigh peak angles in order to start and stop the stimulation of quadriceps muscles, depending on these events. One participant with complete paraplegia was included and was able to propel a recumbent trike using the proposed approach after a very short setting time. This new modality opens the way for a simpler and user-friendly method to automatically design FES-induced cycling stimulation patterns, adapted to clinical use, for multiple bike geometries and user morphologies.