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Acquiring biopotentials with fidelity using low-cost circuits is a significant challenge in biomedical instrumentation. In this perspective, our goal is to investigate the characteristics of the widely applied AD8232®, an analog front-end for biopotential acquisition. We designed and evaluated circuits to acquire the most common biosignals: electrocardiogram (ECG), electromyogram (EMG), and electroencephalogram (EEG). Our findings show that the circuit is suitable for ECG and EMG instrumentation, although it has limitations for EEG signals, particularly concerning the gain. The entire project of the boards is also a contribution of this work as we intend to corroborate open-source do-it-yourself biomedical instrumentation.

Spasticity is a motor condition present in 75 to 88% of children with Cerebral Palsy (CP). One form of treatment is called punctual mechanical oscillation (PO). The current study aimed to study different protocols for the application of PO and the magnitude of their effects. In total, 7children with medical diagnosis of CP and ICD (International Classification of Diseases) were included. The first intervention protocol (Int1) consisted of the application of PO to the spastic muscle tendon and the second intervention protocol (Int2) to the muscle belly ofthe spastic antagonist muscle. For evaluation, the Modified Ashworth Scale (MAS) was used, while simultaneously capturing the mechanomyography (MMG) signals. Data were collected pre-intervention and 1 (Post1), 15 (Post15), 30 (Post30), 45 (Post45), and60 (Post60) minutes after the interventions. The MAS values (median ± interquartile range) post intervention were statistically lower when compared to the pre values in the 2 protocols studied; in Int1between Pre (2 ± 0) andPost15 (0 ± 1.75), Post30 (0 ± 1), Post45 (1 ± 1),and Post60 (1 ± 1), and in Int2only between Pre (2 ± 1) and Post1 (0 ± 1).The values found in the MMG in both its temporal and spectral domains did not follow a pattern (p>0.05). The comparison between the protocols did not demonstrate statistical differences in any characteristics (MAS, MMGMF, and MMGRMS). However, PO was shown to be a therapeutic resource that modulated spasticity for up to 60 minutes after its application, and PO could contribute as a tool to aid the treatment of spasticity. Introdução: A espasticidade é uma condição motora presente em 75 a 88 % das crianças com Paralisia Cerebral (PC). Uma forma de tratamento é a chamada oscilação mecânica pontual (OP). Este trabalho teve por objetivo estudar diferentes protocolos de aplicação da OP e a magnitude de seus efeitos. Métodos: Foram incluídas 7 crianças com diagnóstico médico de PC e CID (Classificação Internacional de Doenças). O primeiro protocolo de intervenção (Int1) consistiu na aplicação de OP no tendão do músculo espástico e o segundo protocolo de intervenção (Int2) no ventre muscular do músculo antagonista espástico. Para avaliação, foi utilizada a Escala Modificada de Ashworth (EMA), capturando simultaneamente os sinais da mecanomiografia (MMG). Os dados foram coletados antes da intervenção e 1 (Pós1), 15 (Pós15), 30 (Pós30), 45 (Pós45) e 60 (Pós60) minutos após as intervenções. Resultados: Os valores do MAS (mediana ± intervalo interquartil) pós-intervenção foram estatisticamente menores quando comparados aos pré-valores nos 2 protocolos estudados; no Int1 entre Pré (2 ± 0) e Pós15 (0 ± 1,75), Pós30 (0 ± 1), Pós45 (1 ± 1) e Pós60 (1 ± 1) e no Int2 apenas entre Pré (2 ± 1) e Pós1 (0 ± 1). Os valores encontrados no MMG nos domínios temporal e espectral não seguiram um padrão (p> 0,05). Conclusão: A comparação entre os protocolos não demonstrou diferenças estatísticas em nenhuma característica (EMA, MMGMF, and MMGRMS). No entanto, a OP mostrou-se um recurso terapêutico que modulou a espasticidade por até 60 minutos após a sua aplicação, e a OP poderia contribuir como uma ferramenta para auxiliar o tratamento da espasticidade.

Made available in DSpace on 2021-06-25T10:29:02Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-07-01 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) People with spinal cord injury (SCI) may have their paralyzed muscles activated through functional electrical stimulation (FES). This neuromodulation technique has been used frequently to assist in controlling the movement of neuroprostheses. Electroencephalography (EEG) is able to trigger FES from the motor imagery captured through movements intentions. This research presents an isometric neuromuscular control system of the quadriceps muscle activated by EEG. Additionally, the detection of neuromuscular fatigue through the mechanomyography (MMG) technique is proposed, which is used to shut-off the system. A pilot study was performed on a chronic 42-year-old paraplegic (no voluntary contraction below the spinal cord injury level T8) volunteer. To do so, the training procedure for EEG signals was divided into the calibration and feedback phases. In the first one, four EEG channels and the Linear Discriminant Analysis (LDA) classifier were used to classify between motor imagery of the right leg and remain at rest. The maximum accuracy obtained during this stage was 77%. In the feedback phase, the volunteer was able to activate FES through brain–computer interface (BCI) in two tests (defined as Test 1 and Test 2) with the same procedure in different days. The closed-loop force control was tested with the setpoint of 2 kgf and 2.5 kgf and proved to be stable on both tests, successfully turning off the FES using the fatigue threshold from the MMG signal, being the main contribution of this work. Universidade Estadual Paulista Júlio Mesquita Filho (UNESP) Faculdade de Engenharia Campus Ilha Solteira, Av. Brasil Sul, 56 Universidade Tecnológica Federal do Paraná (UTFPR), Marcílio Dias, 635 Universidade Tecnológica Federal do Paraná (UTFPR), Avenida Sete de Setembro 3165 Universidade Estadual de Londrina (UEL) – Departamento de Anatomia Laboratório de Engenharia Neural e de Reabilitação, Rodovia Celso Garcia Cid – Pr 445, Km 380 Instituto Senai de Tecnologia da Informação e Comunicação (ISTIC) Laboratório de Sistemas Eletrônicos - Embarcados e de Potência IoT e Manufatura 4.0, Rua Belém 844 Universidade Estadual Paulista Júlio Mesquita Filho (UNESP) Faculdade de Engenharia Campus Ilha Solteira, Av. Brasil Sul, 56

Functional electrical stimulation (FES) is a method of activating paralyzed muscles. During FES application, fast muscle fatigue can occur (the inability of stimulated muscles to generate force). Therefore, it is beneficial to estimate the muscle fatigue for FES closed-loop control for walking to prevent unexpected muscle collapse and adapt the FES strategy in real time. Mechanomyography (MMG) is a noninvasive technique for registering myofiber vibrations, representing an ideal candidate for the provision of feedback. The hypothesis was that MMG signals could effectively detect muscle fatigue and, thus, provide feedback. We tested this hypothesis by analyzing the wavelet transform of signals from an MMG sensor positioned over the rectus femoris muscle during electrically evoked contractions in subjects with spinal cord injury (SCI). The signals were collected from a total of 24 lower limb muscles. We investigated both legs of 15 participants with spinal cord injury (male, YOA = 27.13 ± 5.05, M = 75.8 ± 10.35 kg, and H = 1.78 ± 0.07 m, American Spinal Injury Impairment Scale (AIS) A and B). All MMG signals were analyzed in 12 frequency bands from 5 to 53 Hz. We found different trends in the magnitudes in different frequency bands. The magnitude decreased in 13, 16, 20, 25, and 35 Hz bands in correlation with fatigue. The greatest statistical difference was found at 20 Hz and 25 Hz. This result suggests that processed MMG signals indicate muscle fatigue and can, thus, be used as the feedback in FES systems.

Aims: This study tested whether performing exergames with and without additional external load could induce to different internal load demand for young adults. Methods: Fifteen young women (24.4 ± 4.06 years) participated in the study. Electromyography (EMG) activity, heart rate (HR) and overall and local rating of perceived exertion (RPE) were determined in “Just Dance” and “Ski” exergames without additional external load and with additional external load of 5% of body mass attached bilaterally to the ankles in “Just Dance” and using a weight vest in “Ski”. Results: EMG, HR and overall RPE presented similar responses between loads in both exergames (p>.05). However, local RPE differentiate internal load only in “Just Dance”, with higher values with additional load (with additional load: 11.2 ± 2.1 RPE; without additional load: 10.3 ± 1.4 RPE; p = .037). Conclusion: Therefore, performing exergames with an additional external load of 5% of young women body mass did not induce different internal load demand in “Just Dance” and “Ski” exergames compared to performing such games without external load. However, the greater local RPE in “Just Dance” exergame after adding the external load suggests that a higher amount of load (i.e., > 5% of body mass) to this population may generate different internal load demand.

Introduction: Functional Electrical Stimulation (FES) is a technique used in the restoration and generation of movements performed by subjects with neuromuscular disorders such as spinal cord injury (SCI). The purpose of this article is to outline the state of the art and perspectives of the use of FES in artificial motor control of the upper limbs in paretic or plegic people. Methods The databases used in papers selection were Google Scholar and Capes’ Portals as well as proceedings of the Annual Conference of the International Functional Electrical Stimulation Society (IFESS). Results Approximately 85% of the reviewed studies showed FES profile with pulse duration ranging from 1 to 300 μs and modulating (burst) frequency between 10 and 40 Hz. Regarding the type of electrodes, 88% of the studies employed transcutaneous electrodes. Conclusion We concluded that FES with closed-loop feedback and feedforward are the most used and most viable systems for upper limbs motor control, because they perform self-corrections slowing neuromuscular adaptation, allowing different planes and more range of movement and sensory-motor integration. One of the difficulties found in neuroprosthesis systems are electrical wires attached to the user, becoming uninteresting in relation to aesthetics and break. The future perspectives lead to a trend to miniaturization of the stimulation equipment and the availability of wireless networks, which allow the attachment of modules to other components without physical contact, and will become more attractive for daily use.

Introduction: Signal analysis involves time and/or frequency domains, and correlations are described in the literature for voluntary contractions. However, there are few studies about those correlations using mechanomyography (MMG) response during functional electrical stimulation (FES) elicited contractions in spinal cord injured subjects. This study aimed to determine the correlation between spectral and temporal MMG features during FES application to healthy (HV) and spinal cord injured volunteers (SCIV). Methods: Twenty volunteers participated in the research divided in two groups: HV (N=10) and SCIV (N=10). The protocol consisted of four FES profiles transcutaneously applied to quadriceps femoris muscle via femoral nerve. Each application produced a sustained knee extension greater than 65º up to 2 min without adjusting FES intensity. The investigation involved the correlation between MMG signal root mean square (RMS) and mean frequency (MF). Results: HV and SCIV indicated that MMGRMS and MMGMF variations were inversely related with -0.12 ≥ r ≥ -0.82. The dispersion between MMGMF and MMGRMS reached 0.50 ≤ r2 ≤ 0.64. Conclusion The increase in MMGRMS and the decrease in MMGMF may be explained by the motor units coherence during fatigue state or by motor neuron adaptation (habituation) along FES application (without modification on parameters).

Introduction Iontophoresis is a noninvasive technique used to increase transdermal penetration of substances through the skin layer (epidermis, dermis and hypodermis) in a controlled manner. Technological advance in recent decades have provided reduced cost of equipment needed for implementation, which allowed for the expansion of this technique. Objective The aim of this paper is to present the state of the art on iontophoresis, ranging from the atomic characteristics of the ion formation to the current applications of the technique. Methods Were researched papers from databases: IOP publishing, ScienceDirect, Pubmed, Springer, IEEE Xplore, Google Scholar and books with keywords iontophoresis, ions, topical applications between 1967 and 2010. Results Were selected (number of papers and database) 1 IOP Publishing, 1 from ScienceDirect, Central, 1 from Springer, 2 from PubMed, 11 from IEEE Xplore, 35 from Google Scholar, and 15 books, totaling 66 references and websites with nationally marketed electrotherapy products. Conclusion Iontophoresis is suitable for applications such as acetic acid (calcific tendinitis and myositis ossificans), calcium chloride and magnesium sulfate (control of musculoskeletal spasms), dexamethasone (inflammation), lidocaine (inflammation of soft tissues), zinc oxide (rheumatoid arthritis). It is also used in cosmetic applications with devices attached to the skin and for eye treatment aimed at specific tissues of the eye, providing a treatment option for various eye diseases, reducing the complications secondary to traditional methods of treatment. The advantages are the significant increase in the release and control of therapeutic agents, including drugs with high molecular weight. The disadvantages of iontophoresis are the complexity of the drug release system and prolonged exposure of the skin to an electrical current. Introdução A iontoforese é uma técnica não invasiva utilizada para aumentar, de forma controlada, a penetração transdermal de substâncias através das camadas da pele (epiderme, derme e hipoderme). O avanço tecnológico nas últimas décadas proporcionou uma redução no custo dos equipamentos necessários à sua aplicação, o que possibilitou a expansão dessa técnica. Objetivo Apresentar o estado da arte sobre iontoforese, abrangendo desde as características atômicas da formação do íon até as atuais aplicações da técnica. Métodos Foram pesquisados artigos das bases de pesquisa: IOP publishing, ScienceDirect, Pubmed, Springer, IEEE Xplore, Google Scholar e livros com os unitermos: iontophoresis, ions, topical applications entre os anos de 1967 e 2010. Resultados Foram selecionados (número de artigos e base de pesquisa) 1 da IOP Publishing, 1 da ScienceDirect, 1 da Springer, 2 da PubMed, 11 da IEEE Xplore, 35 do Google Scholar e 15 livros, totalizando 66 referências, além de websites com produtos comerciais nacionais de eletroterapia. Conclusão A iontoforese é indicada para aplicações como de ácido acético (tendinite calcificante e miosite ossificante), cloreto de cálcio e sulfato de magnésio (controle de espasmos musculoesqueléticos), dexametasona (inflamação), lidocaína (inflamação de tecidos moles), óxido de zinco (artrite reumatóide). Também é utilizada em aplicações cosméticas com dispositivos aderidos à pele e em tratamento ocular visando tecidos específicos do olho, oferecendo uma forma de tratamento para diversas doenças oculares, diminuindo as complicações apresentadas em métodos clássicos de tratamento. As vantagens são o significativo aumento na liberação e controle de agentes terapêuticos, incluindo fármacos com alto peso molecular. As desvantagens encontradas na iontoforese são a complexidade do sistema de liberação do fármaco e exposição prolongada da pele a uma corrente elétrica.

INTRODUÇÃO: O potencial de ação (PA) origina-se graças a uma perturbação do estado de repouso da membrana celular, com consequente fluxo de íons, por meio da membrana e alteração da concentração iônica nos meios intra e extracelular. OBJETIVOS: Sintetizar o conhecimento científico acumulado até o presente sobre o potencial de ação neural e o seu processo de adaptação sob aplicação de um estímulo constante. MATERIAIS E MÉTODOS: Busca realizada nas bases Springer, ScienceDirect, PubMed, IEEE Xplore, Google Acadêmico, Portal de Periódicos da Capes, além de livros referentes ao assunto. O idioma de preferência selecionado foi o inglês, com as keywords: action potential; adaptation; accommodation; rheobase; chronaxy; nerve impulse. Efetuou-se a procura de artigos com uma janela de tempo de 1931 a 2010 e livros de 1791 a 2007. RESULTADOS: Dos trabalhos selecionados, foram extraídas informações a respeito dos seguintes tópicos: potencial de ação e suas fases; condução nervosa; reobase; cronaxia; acomodação; e adaptação neuronal. CONCLUSÃO: Um estímulo que crie PA, se aplicado de maneira constante, pode reduzir a frequência de despolarizações em função do tempo e, consequentemente, adaptar a célula. O tempo que a célula demora, na ausência de estímulos, para recuperar sua frequência original é definido como desadaptação. INTRODUCTION: The action potential (AP) arises due to a disturbance of the resting state of the cell membrane with consequent flow of ions across the membrane and ion concentration changes in intra and extra cellular space. OBJECTIVES: This article aims to summarize the scientific knowledge accumulated to date on the action potential and neural adaptation in the process of applying a constant stimulus. MATERIALS AND METHODS: This is a literature review on the bases Springer, ScienceDirect, PubMed, IEEE Xplore, Google Scholar, Capes Periodicals Portal as well as books on the topic. The selected preferred language was English with the keywords: action potential; adaptation, accommodation; rheobase; chronaxy; nerve impulse. We conducted a search of articles with a wide time window from 1931 to 2010 and books from 1791 to 2007. RESULTS: In the selected studies was extracted information about the following topics: action potential and its stages; nerve conduction; rheobase; chronaxie, accommodation, and adaptation. CONCLUSION: A stimulus that creates AP, if applied consistently, can reduce the frequency of depolarization as a function of time and, consequently, to adapt the cell. The time it takes the cell in the absence of stimuli, to recover its original frequency, is defined as a disadaptation.