Abstract 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: The evaluation of muscular tissue condition can be accomplished with mechanomyography (MMG), a technique that registers intramuscular mechanical waves produced during a fiber's contraction and stretching that are sensed or interfaced on the skin surface. OBJECTIVE: Considering the scope of MMG measurements and recent advances involving the technique, the goal of this paper is to discuss mechanomyography updates and discuss its applications and potential future applications. METHODS: Forty-three MMG studies were published between the years of 1987 and 2013. RESULTS: MMG sensors are developed with different technologies such as condenser microphones, accelerometers, laser-based instruments, etc. Experimental protocols that are described in scientific publications typically investigated the condition of the vastus lateralis muscle and used sensors built with accelerometers, third and fourth order Butterworth filters, 5-100Hz frequency bandpass, signal analysis using Root Mean Square (RMS) (temporal), Median Frequency (MDF) and Mean Power Frequency (MPF) (spectral) features, with epochs of 1 s. CONCLUSION: Mechanomyographic responses obtained in isometric contractions differ from those observed during dynamic contractions in both passive and functional electrical stimulation evoked movements. In the near future, MMG features applied to biofeedback closed-loop systems will help people with disabilities, such as spinal cord injury or limb amputation because they may improve both neural and myoelectric prosthetic control. Muscular tissue assessment is a new application area enabled by MMG; it can be useful in evaluating the muscular tonus in anesthetic blockade or in pathologies such as myotonic dystrophy, chronic obstructive pulmonary disease, and disorders including dysphagia, myalgia and spastic hypertonia. New research becomes necessary to improve the efficiency of MMG systems and increase their application in rehabilitation, clinical and other health areas.

INTRODUCTION: Functional electrical stimulation (FES) may evoke movements in people with movement impairments due to neurological lesion. The mean value of electrical current or voltage during FES depends on the stimulatory profile parameters. To investigate the relationship between peak and mean amplitudes of the stimulator output voltage while causing a knee extension angle change from 90º to 40º to choose the best and safest profile to be applied in people who have suffered a spinal cord injury. METHODS: Healthy (N = 10) volunteers and those with spinal cord injuries (N = 10) participated in this study. Each FES profile (P1, P2, P3 and P4) had 1-kHz pulses (100 µs or 200 µs on and 900 µs or 800 µs off) with burst frequencies of 50 Hz (3 ms on and 17 ms off) or 70 Hz (3 ms on and 11 ms off) and peak amplitudes set between 53-125V for healthy volunteers and 68-198 V for volunteers with spinal cord injury. RESULTS: The highest mean amplitude were obtained using a FES profile with active/total pulse period of 200 us/1000 us and burst frequency of 3ms/14ms. The best results of mean amplitude were observed using a FES profile duty cycle of 10% for pulses (100 µs/1000 µs) and 15% for bursts (3 ms/20 ms). CONCLUSION: The FES profile (100 µs - 50 Hz) seems to be the most suitable for both groups, inasmuch as it presents smaller mean amplitudes and peak amplitudes similar to other FES profiles.

O presente trabalho apresenta a proposta de um Programa para o desenvolvimento do Sistema Nacional de Inovação de Produtos Médicos - SNIPM no âmbito do Sistema Único de Saúde - SUS, de forma integrada e alinhada com as ações do Ministério da Saúde. Os conhecimentos e as ferramentas em engenharia clínica permitiram realizar uma análise diferenciada do contexto socioeconômico do setor, a sistematização e a percepção dos fatores e atores que induzem ou retardam o crescimento tecnológico do setor. Neste artigo, buscou-se contextualizar o setor de produtos médicos no Brasil à luz da atual conjuntura socioeconômica nacional e mundial, caracterizando-o como de grande indutor de atividades inovadoras. Posteriormente, são abordadas as definições e teorias sobre os Sistemas Nacionais de Inovação e as especificidades do SNIPM no Brasil, apresentando seus atores incluindo suas atribuições e competências. A metodologia utilizada para a coleta e análises de dados econômicos é apresentada, de modo a caracterizar a importância deste segmento para a economia nacional e suas potencialidades na indução do surgimento de tecnologias inovadoras no SNIPM. A análise dos dados setoriais coletados durante a pesquisa é apresentada, como o objetivo de quantificar e apresentar os números socioeconômicos do setor de produtos. Por fim, é apresentado o delineamento de um Programa destinado acatalisar o desenvolvimento do SNIPM considerando as demandas tecnológicas e prioridades do SUS e as dos mercados-alvo do setor produtivo. A proposta, que foi desenvolvida e implementada no Ministério da Saúde, pode se constituir como uma das ferramentas no âmbito do SUS destinadas a fortalecer e modernizar o setor de equipamentos e materiais de uso em saúde, visando à ampliação da capacidade inovadora das empresas e mudança do seu patamar competitivo.

This paper presents a proposal of a program for the development of the Brazilian National Innovation System for Medical Products (SNIPM) under the National Health System (SUS) integrated and aligned with the actions of the Brazilian Ministry of Health. Clinical engineering knowledge and tools allowed performing a differentiated socio-economic analysis of the sector, the systematization and the perception of actors and factors that induce or retard the growth of the technology sector. In this article, the medical devices sector in Brazil was first contextualized to in the light of current national and global socio-economic conjuncture, in order to characterize it as a major inducer of innovative activities. The definitions and theories about the National Innovation Systems are described, followed by a discussion of the specifics of SNIPM in Brazil, with its actors, including their duties and responsibilities. The methodology for the collection and analysis of economic data, were shown, in order to characterize the importance of this sector to the national economy and its potential to induce the rising of innovative technologies whithin the SNIPM. The analysis of industry data is presented, which attempts to present and comment on some industry data collected during a survey. In the Results section, it is presented the design of a program used to to catalyze the development of the SNIPM considering the technological demands and priorities of the SUS and the target markets of the productive sector. The proposed program, which was developed and implemented within the Brazilian Ministry of Health, can become one of the tools within the SUS to strengthen and modernize the sector of medical equipments and materials, aiming to increase the innovative capacity of firms and change its competitive standing.

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.