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

International audienceBackground: 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

Can the Voluntary Drive to a Paretic Muscle be Estimated from the Myoelectric Signal during Stimulation?

Patients with SCI sometimes recover lost function after using FES. This phenomenon, known as the carry-over effect, is not fully understood. One theory used to explain this mechanism is that electrical stimulation of the peripheral nerve causes antidromic action potentials to reach the anterior horn cells in time with the patient’s voluntary effort. This may reinforce the motor pathways and consequently restore voluntary control. However, the theory has never been properly tested and testing requires a method of measuring the voluntary drive. This project aims to find out whether it is possible to estimate the voluntary drive from measured myoelectric signals. The project is based on an FES cycling system with the ability to adjust the stimulation intensity relating to the corresponding voluntary drive. In paretic muscles, the weak voluntary contraction produces an EMG response. The EMG signal cannot be used directly as an indication of the voluntary drive because of the presence of stimulus artefact and reflexes. Two methods were investigated to estimate the voluntary drive. A time domain method was tested using RMS EMG extracted from a range of time windows following the stimulation pulse. This approach was unsatisfactory because the large variations seen in the RMS EMG amplitudes for the same power output as well as the low sensitivity of it to the change of power output. A frequency domain approach was then tested using coherence between co-contracting muscles. It was encouraging to see that the area under the coherence curve in the β band reflected changes in the power output level. However, further tests showed that this area was also greatly influenced by exercise time, becoming unpredictable after 3 minutes. In conclusion, neither of the two methods of using the myoelectric signal from muscles under stimulation is practical for the estimation of voluntary drive

Bionikai megoldások gerincvelősérültek mozgás-rehabilitációjában és sportjában : Funkcionális Elektromos Izomingerléssel végzett kerékpározás

A gerincvelősérülés egy olyan nagyon súlyos sérülés, ami többnyire fiatalokat érint, és aminek következménye a motoros és a szenzoros funkciók, illetve képességek elvesztése. A sérülés után ezek a fiatalok általában mozgásszegény életmódot élnek, hiszen bénult végtagjaikat nem tudják akaratlagosan, aktív izomerő kifejtésével mozgatni. A mozgásszegény életmód elsősorban abból adódik, hogy a bénulás következtében például kerekesszékbe kényszerülnek, amely a fizikai aktivitás lehetőségét jelentősen beszűkíti, és a mindennapi élet megkövetelte mozgás is igen nagy erőfeszítésbe kerül. A mozgásszegény életmódnak számos káros következménye van a sérültek általános egészségi állapotára nézve. Ezért rendkívül fontos, hogy lehetővé tegyük az aktív izomerő kifejtését a bénult végtagokban. Az idegrendszeri sérülés következtében mozgási képességeiket részben elvesztett emberek számára történő korszerű rehabilitációs kezelések olyan szabályozott gyakorlatokon alapulnak, amelyeket robotikai, bionikai módszerek és funkcionális elektromos izomingerlés (FES) tesz lehetővé. A gerincvelősérült emberek számára a mozgás, a sport rendkívüli fontosságú, annak érdekében, hogy általános fiziológiai állapotukat megőrizzék, javítsák és hosszú ideig megőrizzék. Paraplég emberek nem képesek alsó végtagjaikban aktív, akaratlagos erő kifejtésére, ezért az aktív izomerőt és ezáltal az alsó végtagjaikkal végzett sporttevékenységet csak funkcionális elektromos izomingerléssel érhetik el. A FES nem csak az izmok erősítését, hanem konkrét hasznos mozgási feladatok végrehajtását szolgálja. Ebben a közleményben a funkcionális elektromos ingerlés segítségével létrehozott kerékpározó mozgásról írunk. Ezt kerékpár ergométeren is végezhetik a gerincvelősérültek, valamint arra alkalmas triciklin is. A kerékpározó mozgás elősegítésére multidiszciplináris tudományos kutatások szükségesek. A triciklin végzett FES kerékpározásban már nemzetközi versenyeket is rendeznek

Functional electrical stimulation cycling exercise after spinal cord injury: a systematic review of health and fitness-related outcomes.

ObjectivesThe objective of this review was to summarize and appraise evidence on functional electrical stimulation (FES) cycling exercise after spinal cord injury (SCI), in order to inform the development of evidence-based clinical practice guidelines.MethodsPubMed, the Cochrane Central Register of Controlled Trials, EMBASE, SPORTDiscus, and CINAHL were searched up to April 2021 to identify FES cycling exercise intervention studies including adults with SCI. In order to capture the widest array of evidence available, any outcome measure employed in such studies was considered eligible. Two independent reviewers conducted study eligibility screening, data extraction, and quality appraisal using Cochranes' Risk of Bias or Downs and Black tools. Each study was designated as a Level 1, 2, 3 or 4 study, dependent on study design and quality appraisal scores. The certainty of the evidence for each outcome was assessed using GRADE ratings ('High', 'Moderate', 'Low', or 'Very low').ResultsNinety-two studies met the eligibility criteria, comprising 999 adults with SCI representing all age, sex, time since injury, lesion level and lesion completeness strata. For muscle health (e.g., muscle mass, fiber type composition), significant improvements were found in 3 out of 4 Level 1-2 studies, and 27 out of 32 Level 3-4 studies (GRADE rating: 'High'). Although lacking Level 1-2 studies, significant improvements were also found in nearly all of 35 Level 3-4 studies on power output and aerobic fitness (e.g., peak power and oxygen uptake during an FES cycling test) (GRADE ratings: 'Low').ConclusionCurrent evidence indicates that FES cycling exercise improves lower-body muscle health of adults with SCI, and may increase power output and aerobic fitness. The evidence summarized and appraised in this review can inform the development of the first international, evidence-based clinical practice guidelines for the use of FES cycling exercise in clinical and community settings of adults with SCI. Registration review protocol: CRD42018108940 (PROSPERO)

Eletrodiagnóstico de estímulo na definição dos parâmetros para prática do ciclismo assistido por eletroestimulação em pessoas com lesão medular

Dissertação (mestrado)—Universidade de Brasília, Faculdade de Ceilândia, Programa de Pós-Graduação em Ciências e Tecnologias em Saúde, 2020.Introdução: A Estimulação Elétrica Funcional (FES, do inglês, Functional Electrical Stimulation) representa estratégia no processo de reabilitação cuja meta inclui acionar músculos paralisados ou enfraquecidos pela Lesão Medular em tarefas específicas. Dentre as tarefas recentemente exploradas, o ciclismo assistido por eletroestimulação ganhou notoriedade mundial e o refinamento dos requisitos para a prática, bem como a dosimetria para eletroestimulação dependem da responsividade do músculo paralisado cuja inervação periférica continua preservada, o que supomos poder ser mais bem definidos por informações fornecidas pelo teste de eletrodiagnóstico por estímulo não-invasivo. Objetivo: Verificar o comportamento dos parâmetros de responsividade à eletroestimulação fornecidos pelo eletrodiagnóstico por estímulo não-invasivo em uma série de casos de pessoas com lesão medular candidatas à iniciar treinamento para a prática do ciclismo assistido por eletroestimulação, buscando associações e indícios que permitam se formular hipóteses acerca da dosimetria ideal para estimulação, bem como estabelecer critérios apropriados para eleger praticantes. Métodos: Delineamos um estudo observacional do tipo transversal em série de casos que aconteceu subsequente ao recrutamento de 14 indivíduos com lesão medular traumática, candidatos a participar de programa de ciclismo assistido por eletroestimulação. Ao final, uma amostra representativa de 7 casos foi testada para se obter valores de reobase, cronaxia, acomodação e índice de acomodação, explorados em modelo preditivo do nível de força muscular avaliado conforme recomendação da Medical Research Council e caracterizado por outras variáveis independentes e de interesse para se estabelecer requisitos para prática (condição e estado de saúde) bem como para a dosimetria (características da contração resultante da estimulação). Estatística descritiva e analítica paramétrica e não-paramétrica, bem como poder estatístico foram o processamento de base para inferências dada a natureza do delineamento em série de casos. Resultados: A acomodação apresentou tendência a se correlacionar com a intensidade de corrente nos níveis 1 (Reto femoral esquerdo e vasto lateral direito), 2 (reto femoral esquerdo) e 3 (reto femoral esquerdo e vasto lateral esquerdo) e mostrou correlação significativa com os níveis 1 (vasto medial direito) e 2 (reto femoral direito e vasto lateral esquerdo). A reobase apresentou tendência a se correlacionar com a intensidade de corrente nos níveis 2 (vasto lateral esquerdo e vasto medial esquerdo) e 3 (vasto medial esquerdo), revelando uma prevalência de correlação no músculo quadríceps esquerdo (63,63%). Conclusão: A acomodação mostrou ser um candidato a fator preditivo de intensidade de corrente para promover contração muscular de quadríceps femoral em pessoas com lesão medular traumática responsivas ao eletrodiagnóstico de estímulo e elemento formador da dosimetria inicial a prática do ciclismo assistido por eletroestimulação.CAPES, CNPq, FAPDF, INRIA (França) e MCTIC.Introduction: Functional Electrical Stimulation (FES) represents a rehabilitation process strategy whose goal includes triggering muscles paralyzed or weakened by spinal cord injury in specific tasks. Among the tasks recently explored, electrostimulation-assisted cycling has gained worldwide notoriety and the refinement of the requirements for practice, as well as dosimetry for electrostimulation depends on the paralyzed muscle’s responsiveness whose peripheral innervation remains preserved, which we assume may be better defined by information provided by the noninvasive stimulus electrodiagnosis test. Objective: To monitor the electrostimulation responsiveness parameters behavior provided by electrodiagnosis with spinal cord injury people in series of cases which are candidates to start the practice of electrostimulation-assisted cycling, seeking associations and indications that allow to formulate eligibility and dosimetry hypotheses. Methods: We designed an observational cross-sectional study in a series of cases that occurred following the recruitment of 14 individuals with traumatic spinal cord injury, candidates to participate in an assisted electrostimulation cycling program. At the end, a representative sample of 7 cases was tested to obtain rheobase, chronaxie, accommodation and accommodation index values, explored in a predictive assessed muscle strength level model, as recommended by the Medical Research Council and characterized by other independent variables of interest to establish requirements for practice (condition and health status) as well as for dosimetry (stimulation resulting contraction characteristics). Descriptive and parametric and non-parametric analytical statistics, as well as statistical power were the basic processing for inferences given the case series design nature. Results: The accommodation tended to correlate with current intensity at levels 1 (left rectus femoris and right vastus lateralis), 2 (left rectus femoris) and 3 (left rectus femoris and left vastus lateralis) and showed correlation levels 1 (right vastus medialis) and 2 (right rectus femoris and left vastus lateralis). The rheobase tended to correlate with current intensity at levels 2 (left vastus lateralis and left vastus medialis) and 3 (left vastus medialis), revealing a prevalence of correlation in the left quadriceps muscle (63.63%). Furthermore, the evaluation of the lesion’s level, associated with the noninvasive electrodiagnosis stimulus test, can infer about electrostimulation neuromuscular responsiveness. Conclusion: The accommodation proved to be a predictive factor candidate of current intensity to promote femoral quadriceps muscle contraction in people with traumatic spinal cord injury responsive to the electrodiagnosis stimulus and the formative element of initial dosimetry to the electrostimulation assisted cycling practice