Orientador: Fausto Viterbo / Resumo: INTRODUÇÃO: Os nervos periféricos, assim como os demais tecidos do organismo, estão sujeitos a doenças inflamatórias, traumáticas, metabólicas, tóxicas, genéticas e neoplásicas. Estas doenças levam a diferentes tipos e graus de lesões. As lesões nervosas são bem conhecidas pela redução da capacidade funcional e diminuição da qualidade de vida dos pacientes, essas lesões induzem altos gastos socioeconômicos devido à reabilitação prolongada e absenteísmo dos jovens vítimas de trauma. Questiona-se se a Estimulação Elétrica (EE) e a terapia por Laser de Baixa Potência (LBP) teriam capacidade de melhorar a recuperação muscular e nervosa pós - neurorrafia látero - terminal (NLT). OBJETIVO: Analisar a eficiência da EE e da terapia por LBP na manutenção do músculo tibial cranial (MTC) e regeneração do nervo fibular comum pós NLT. MÉTODO: Trabalho aprovado pelo CEUA FMB - UNESP Nº 1154/2015. Foram utilizados 100 ratos da linhagem Wistar, machos, com massa média de 384,33 g e aproximadamente 9 semanas de vida. Os animais foram divididos em seis grupos experimentais. Grupo Controle, Grupo Desnervado, Grupo com Neurorrafia Látero -Terminal (NLT), Grupo com NLT e Estimulação Elétrica (EE), Grupo com NLT e LASER de baixa potência (LBP) e Grupo com NLT e combinação de EE e LBP (LBP+EE). O tratamento foi realizado durante 180 dias. Foram realizados testes funcionais e histológicos. Análise Estatística: Quando comparados os grupos, foi utilizado predominantemente teste Kruskal Wallis e método... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: INTRODUCTION: Peripheral nerves, as well as other tissues of the body, are subject to inflammatory, traumatic, metabolic, toxic, genetic and neoplastic diseases. These diseases lead to different types and degrees of injury. Nerve injuries are well known for reducing functional capacity and decreasing patients' quality of life. These injuries induce high socioeconomic costs due to prolonged rehabilitation and absenteeism of young trauma victims.It is questioned whether Electric Stimulation (ES) and Low Power Laser Therapy (LPLT) would have the capacity to improve muscle and nerve recovery after end to side neurorrhaphy (SEN). OBJECTIVE: To analyze the efficiency of ES and LPLT in the maintenance of cranial tibial muscle (CTM) and regeneration of the common fibular nerve post SEN. METHOD: Work approved by certificate No. 1154/2015 CEUA FMB - UNESP. One hundred Wistar rats, male, with a mean mass of 384.33 g and approximately 9 weeks of life, were used. The animals were divided into six experimental groups. Control group, denervated group, group with neurorrhaphy. Grupo Controle, Grupo Desnervado, Group with SEN, Group with SEN and Electrical Stimulation (ES), Group with SEN and low power LASER (LPL) and Group with SEN and combination of ES and LPL (LPL + ES). The treatment was performed for 180 days. Functional and histological tests were performed. Statistical analysis: When comparing the groups, were used predominantly, the Kruskal Wallis test followed by Dunn´s method and AN... (Complete abstract click electronic access below) / Doutor

O barorreflexo arterial é o principal mecanismo de regulação a curto prazo da pressão arterial (PA), mantendo-a dentro de um estreito limite de variação. A elevação da PA estimula sensores mecânicos (barorreceptores), que levam a uma inibição simpática e aumento da atividade vagal cardíaca, provocando queda (normalização) da PA. A estimulação elétrica de aferências dos barorreceptores é uma técnica que surgiu na década de 60 e, atualmente, vem sendo utilizada em pacientes com hipertensão refratária. Hipotetizamos que a estimulação elétrica do SC seria capaz de promover alterações hemodinâmicas e na modulação autonômica cardiovascular de ratos normotensos e SHR. Sendo assim, o objetivo deste estudo foi caracterizar respostas hemodinâmicas, variabilidade da frequência cardíaca (FC) e PA, e avaliar alterações vasculares à estimulação elétrica do seio carotídeo (SC) em ratos normotensos ou espontaneamente hipertensos (SHR). Ratos Wistar ou SHR, com 300g (15 a 18 semanas) foram anestesiados (ketamina e xilazina) e implantados com eletrodos ao redor do SC e cânula na artéria femoral. No dia seguinte, após registro basal da PA, o SC dos ratos foi estimulado com pulsos de 1 mA, 1 ms e 15, 30, 45 ou 60 Hz durante 20 s. A seguir, um estímulo prolongado (60 min) com pulsos de 1 mA, 1 ms e 30 Hz foi aplicado ao SC dos ratos de forma contínua ou intermitente (20/20s ON/OFF). Um grupo distinto de SHR foi implantado (SC) com um estimulador miniaturizado capaz de gerar, ininterruptamente, pulsos de 3 V, 1 ms, e 30 Hz, de modo intermitente (20/20s ON/OFF). Nesses animais, no dia seguinte ao implante dos eletrodos, foi realizado um registro basal da PA e o estimulador foi ligado, estimulado o SC durante 48 h. Após o termino da estimulação, um novo registro da PA foi realizado e, ao final, o leito mesentérico dos ratos foi removido para análise de reatividade vascular. A estimulação elétrica de curta duração (20 s) provocou uma resposta hipotensora, que foi maior em SHR (?= -16 a -48 mmHg, n=14) do que em ratos normotensos (?= -19 a -28 mmHg, n=10). A hipotensão causada pela estimulação do SC foi frequência dependente apenas nos SHR. Uma bradicardia, semelhante em ambos os grupos (Wistar e SHR), e não dependente da frequência de estimulação, também foi observada com a estimulação do SC. Na estimulação prolongada (60 min), realizada de forma contínua ou intermitente, também houve hipotensão e bradicardia que se mantiveram durante todo o período de estímulo. A hipotensão durante o estímulo de 60 min do SC também foi maior em SHR (?-38 ± 9 mmHg) do que em ratos Wistar (-15 ± 5 mmHg). A análise simbólica, antes e durante a estimulação do SC, no grupo que recebeu estimulação contínua, revelou um aumento na porcentagem de sequências tipo 2UV da FC (relacionadas à modulação vagal cardíaca) de 37 ± 3 para 45 ± 4 %. A análise espectral mostrou diminuição na potência do espectro da PA na banda de LF (relacionada à modulação simpática cardíaca e vascular) de 3.6 ± 0.3 para 0.7 ± 0.1 mmHg2 apenas em animais normotensos. Os SHR estimulados cronicamente (48 h) tiveram uma PA menor após o final do estímulo (173 ± 5 vs 150 ± 5 mmHg). Entretanto, a variabilidade da FC e da PA não foi alterada pela estimulação crônica do SC. Adicionalmente, o estímulo elétrico crônico do SC promoveu aumento na reatividade das artérias mesentéricas à Acetilcolina, e à fenilefrina, tanto na presença como na ausência do endotélio. A resposta hipotensora perdurou até 60 minutos após o desligamento do dispositivo de estimulação. Concluindo, a estimulação elétrica do SC de ratos acordados, normotensos ou SHR é efetiva em diminuir a PA e FC além de promover alterações na variabilidade da FC e da PA condizentes à redução da modulação simpática em animais normotensos. Adicionalmente, a estimulação crônica do SC promoveu alterações em vasos de resistência. / Arterial baroreflex is the main short-term regulation mechanism of blood pressure (BP), keeping it under narrow limits of variation. The increasing of BP stimulates mechanical sensors (baroreceptors), which lead to inhibition of sympathetic drive and increasing cardiac activity of vagus nerve, resulting in decrease (normalization) of the BP. Electrical stimulation of afferent baroreceptor is an approach that emerged in the 60s and is now being used in patients with resistant hypertension. We hypothesized that electrical stimulation of CS promote hemodynamic and autonomic responses in normotensive and SHR. The aim of this study was to characterize hemodynamic responses, heart rate (HR) and BP variability, and evaluate vascular changes to electrical stimulation of the carotid sinus (CS) in normotensive or spontaneously hypertensive rats (SHR). SHR and Wistar rats with 300g (15 to 18 wk) were anesthetized (ketamine and xylazine) and implanted with electrodes in CS and a catheter into femoral artery. On the next day, after baseline recording of the BP, animals were subjected to electrical stimulation of CS with pulses of 1 mA, 1 ms and 15, 30, 45 or 60 Hz during 20 s. Following, a continuously or intermittently (20 / 20s ON / OFF) prolonged stimulation (60 min) with pulses of 1 mA, 1 ms and 30 Hz was applied to CS of rats. Another SHR group was implanted with a miniaturized stimulator connected to CS electrodes, capable of generating uninterruptedly pulses of 3 V, 1 ms, and 30 Hz, intermittently (20/20s ON/OFF). On the next day, after baseline recording of BP, the stimulator was turned on, and CS was stimulated during 48 h. After the end of stimulation, another BP recording was performed and the mesenteric bed of rats was removed for analysis of vascular reactivity. Short-term (20 s) electrical stimulation of CS induced a hypotensive response that was greater in SHR (??= -16 to -48 mmHg, n = 14) than in normotensive rats (? = -19 to -28 mmHg, n = 10). Hypotensive response was dependent on stimulation frequency only in SHR. A bradycardic response, similar in both groups (Wistar and SHR) and not dependent of the frequency of stimulation was also observed. In prolonged stimulation (60 min), performed continuously or intermittently, hypotension and bradycardia were observed during whole stimulation period. Hypotensive effect observed during 60 min stimulation of the CS was greater in SHR (-38 ± 9 mmHg) than in Wistar rats (-15 ± 5 mmHg). The symbolic analysis, before and during the stimulation of the CS revealed an increase in the percentage of 2UV type sequences of HR (related to cardiac vagal modulation) from 37 ± 3 to 45 ± 4 %. Spectral analysis showed in the decrease power of BP spectrum in LF band (related to heart and vascular sympathetic modulation) from 3.6 ± 0.3 to 0.7 ± 0.1 mmHg2 only in normotensive animals. SHR chronically stimulated group (48 h) showed lower BP after the end of the stimulus (173 ± 5 vs 150 ± 5 mmHg). However, the variability of HR and BP was not changed by chronic stimulation of the CS. Moreover, chronic electrical stimulation of the CS increased the reactivity of mesenteric arteries to acetylcholine and phenylephrine, both in the presence or absence of the endothelium. The hypotensive response lasted after 60 minutes after the shutdown of the stimulation device. In conclusion, the electrical stimulation of CS in normotensive or SHR conscious rats is effective in decreasing BP and HR and promotes changes in the variability of HR and BP, consistent with reduction of sympathetic modulation in normotensive animals. Additionally, the chronic stimulation of the CS induced changes in resistance vessels.

A estimulação elétrica neuromuscular é um recurso reabilitacional funcional que tem como propósito a recuperação dos movimentos dos membros superiores ou inferiores. Com este recurso, é possível a pessoas que possuem uma lesão medular e que vêem suas vidas modificadas pelo advento da lesão, executarem ações que possam facilitar a sua independência nas habilidades diárias, uma vez que mudanças em seu esquema corporal e limitações reais às suas atividades cotidianas são observadas nestes casos. Acredita-se que seja comum a presença de reações psicológicas a este tratamento, porém, poucos estudos foram registrados até o momento. Considerando-se que uma intervenção que aborde aspectos físicos, psicológicos e sociais destas pessoas é indispensável a qualquer processo reabilitacional, esta pesquisa teve como objetivos identificar e analisar características psicossociais de usuários do programa de estimulação elétrica neuromuscular realizado no Hospital das Clínicas da Universidade Estadual de Campinas, Departamento de Ortopedia e Traumatologia da Faculdade de Ciências Médicas, Laboratório de Biomecânica e Reabilitação do Aparelho Locomotor. Suas concepções, reações e expectativas frente a este tipo de reabilitação também foram investigados, além da identificação das principais necessidades destas pessoas, oferecendo subsídios para a condução de um tratamento psicoterápico adequado ao quadro caracterológico das pessoas com lesão medular submetidas à estimulação elétrica neuromuscular, de forma a favorecer a realização de um processo reabilitacional que os contemplem em sua dinâmica biopsicossocial. Para isso, os participantes desta pesquisa foram divididos em dois grupos distintos. Os que se encontravam no primeiro ano de tratamento e os que o realizavam há mais de um ano. Foi utilizado um roteiro de entrevista semi estruturada que teve como propósito conhecer aspectos, tais como, a visão da pessoa com lesão medular sobre sua própria deficiência, formas de enfrentamento, vida social e familiar, bem como, suas concepções e expectativas no que diz respeito à reabilitação por meio da estimulação elétrica neuromuscular. Os entrevistados consideraram como uma de suas metas, a recuperação total ou parcial das funções que lhes foram subtraídas com a lesão medular, considerando efeitos positivos com a utilização deste tratamento, no alcance de melhorias físicas e psicossociais. Não obstante, eles procuram investir em vários outros aspectos de suas vidas, que não somente o reabilitacional, como por exemplo, os profissionais, familiares, sociais e afetivos / Neuromuscular electrical stimulation is a functional resource for rehabilitation, which aims recover the motions of inferior and superior limbs. With this resource, it is possible for spinal cord injury patients, who had their lives changed due to this injury, to execute actions that can make their independency to every day abilities easier, once changes in their body structure and real limitations to daily activities were noticed in this case. It is believed that the remark of psychological reactions are usual for this treatment, however, a few studies were registrated until the moment. In regarding to an intervention that deals with this patients’ physical and social aspects is essential to any rehabilitation process, this research aims to identify and analyze users’ psycho-social characteristics of neuromuscular electrical stimulation program made at Campinas State University hospital, Orthopedic and Traumatology Department of Medical Science School, Laboratory of Biomechanics and Rehabilitation of Inferior Limbs. Its concepts, reactions and expectations toward this kind of rehabilitation were also investigated, as well as the identification for the leading of a psychotherapeutic treatment appropriate to the characterization of the process of spinal cord injury patients who were subjected to neuromuscular electrical stimulation in order to be biased toward the achievement of a rehabilitational process, which gives to the spinal cord injured person in his/her biopsycho social dynamic. For this, subjects of this research were divided in two different groups. The first group, people who were in the first year of treatment and the second group, people who had been in treatment for more than one year. A schedule of a half-standard interview was used and aimed to know aspects such as spinal cord injured person´s point of view about his/her own disability, how he/she faces it, social and family life as well as his/her concepts and expectations regarding to rehabilitation through neuromuscular electrical stimulation. The total or partial recovering of the functions that were taken by the spinal cord injury was had as one of the patients´ goals, which were worried about the positive effects by using this treatment, within reach physical and psychosocial improvement. They tried to invest in many other aspects of life, such as professional, family, social and affective aspects

La stimulation électrique des tissus neuronaux est une technique largement utilisée dans la recherche en neuroscience et à des fins thérapeutiques. Ce travail est une contribution à la conception des circuits et systèmes électroniques de stimulation. De tels circuits sont requis dans quatre projets multi-disciplinaires en cours dans l’équipe Elibio de l’IMS, présentés dans ce document : STN-Oscillations (ANR 08-MNPS-036) concernant l’étude de la Stimulation Cérébrale Profonde(SCP), HYRENE (ANR 2010-Blan-031601), ayant pour but le développement d’un systèmehybride de restauration de l’activité motrice dans le cas d’une lésion de la moelle épinière, BRAINBOW (European project FP7-ICT-2011-C), ayant pour objectif l’élaboration de neuro-prothèses innovantes capables de restaurer la communication autour de lésions cérébrales, CENAVEX (ANR et NSH AN13-NEUIC-0001-01), visant au développement d’un système de stimulation en boucle fermée pour le contrôle de la respiration. Cette thèse propose une approche de conception globale qui aboutira au développement d’un système multi-applications, prenant en compte les spécificités de chaque contexte.Dans un premier temps, afin d’évaluer les contraintes liées à l’expérimentation in vivo et in vitro, deux stimulateurs spécifiques ont été réalisés. Le premier permet la SCP chronique du rat,résout la contrainte énergétique à l’aide d’une gestion dynamique de l’alimentation. Ce dispositif a été fabriqué et implanté in vivo avec succès. Une expérimentation à long terme a été effectuée afin de valider ses propriétés sur l’animal. Dans un second temps, un autre stimulateur a été conçu en utilisant un FPAA (Field Programmable Analog Array). La conception de ce circuit se concentre sur l’équilibrage des charges nécessaire à l’innocuité des sytèmes. L’architecture obtenue permet une stimulation biphasique adaptative résultant en un faible courant équivalent de fuite (moins d’un nano Ampère). Afin d’aboutir à un stimulateur multi-application, un travail préliminaire de modélisation de l’impédance de l’électrode, l’élément de charge du circuit de stimulation, a été mené. Une méthode de mesure et d’identification d’un modèle non-linéaire est détaillée, basée sur une approche par multi-modèles et fractionnaire.L’approche multi-application est ensuite mise en oeuvre, basée sur un effet d’échelle pour le dimensionnement des stimulateurs. Cet effet d’échelle lie la géométrie de l’électrode, le nombre de canaux requis par application et les niveaux de courant mis en jeu : cet effet permet de proposer une architecture de circuit multi-application. Un circuit intégré démontrant la faisabilité d’un tel système a été conçu, fabriqué et testé avec succès. Un système de stimulation multi-application basé sur ce circuit a été conçu, permettant de nouvelles recherches sur les quatre contextes physiopathologiques présentés.Enfin, un critère de mérite dédié à la stimulation est proposé. Ce critère prend en compte l’efficacité énergétique et l’équilibrage des charges afin d’évaluer le degré d’optimisation d’un circuit ou d’un système. Un tel critère de mérite est un concept novateur qui devrait permettre une optimisation rationnelle des architectures de stimulation. / Electrical stimulation of neural tissues is a widely used technique for both neuroscience explorations and innovative medical devices. This work is a contribution to the design of electrical stimulation circuits and systems. Stimulators are part of the experimental setup in several multi-disciplinary projects conducted at IMS (groupElibio), presented in this document : STN-Oscillations(French ANR 08-MNPS-036), studyingDeep Brain Stimulationmecha-nisms (DBS), HYRENE(French ANR 2010-Blan-031601), aimed at developing a hybrid system couplingartificial and biological neural networks to restore locomotion after spinal cord lesion, BRAINBOW(European Project FP7-ICT-2011-C), working on designing a neuro-prosthesis capable of restoring lost communication between neuronal circuits, CENAVEX(French ANR and American NSH AN13-NEUIC-0001-01), proposing a noveldesign for a closed-loop system for respiration control. This thesis integrates the specificities of each context and considers global therapeuticapplication issues, with the aim of proposing an original, global approach to designing thearchitecture of a multi-application stimulator.First, in order to evaluate the constraints related to ourin vivoandin vitrocontexts, anembedded stimulator for chronic DBS experiments in rodents was developed and successfullyimplantedin vivo. This design was optimized for power management during long-term experi-ments. The stimulator characteristics were assessed with behavioural tests on a rat population.Then a second, specific stimulator was designed usingField Programmable Analog Arraysforaccurate charge balancing, as well as to fulfil strong constraints to ensure tissue integrity. Theproposed charge-sensing architecture produced adaptive biphasic stimulation with sub-nanoampere DC-equivalent current.With a view to a global approach to stimulator design, an accurate model of the electrodeimpedance was built, to represent the concrete load of a stimulator. A measurement protocolbased on biphasic current-controlled solicitations and a modelling procedure relying on anoriginal fractional multi-model are described.The first step in this multi-application design approach was to investigate an electrical sizingscale effect. This involves electrode geometry, the number of channels per application, and theimplied current levels. A proof-of-concept ASIC was designed and successfully tested. A boardfor adaptive stimulation was then able to be deployed in the ongoing research projects.Finally, a dedicated Figure of Merit is proposed for stimulation. This criterion takes energyefficiency and charge balancing into account to quantify the degree of optimization of a circuitor system. This Figure of Merit is a novel concept that facilitates rational optimization ofstimulation architectures.

Selective stimulation and conduction block of specific nerve fibers has been a major area of research in neuroscience. The potential clinical and neurophysiological applications have warranted reliable techniques for transiently blocking conduction through nerves. High Frequency Alternating Current (HFAC) waveforms have been found to induce a reversible and repeatable block in peripheral nerves; however the effect of these waveforms on the neural activity of individual fiber types is currently unknown. Understanding this effect is critical if clinical applications are to be pursued. This dissertation work utilized extracellular electrophysiological techniques to characterize the activity of different fiber type populations in peripheral nerves during application of HFAC waveforms. First, we investigated the phenomenon in the homogeneous unmyelinated nerves of the sea-slug, Aplysia californica. Although complete reversible block was demonstrated in these nerves, a non-monotonic relationship of block threshold to frequency was found which differed from previously published work in the field. We then investigated the effect of HFAC waveforms on amphibian mixed nerves and studied the response of specific fiber types by isolating different components of the compound action potential. We validated our results from the Aplysia nerves by determining the block thresholds of the larger diameter, myelinated A-fibers and comparing them with those of the smaller diameter, unmyelinated C-fibers. We also showed that block threshold behavior during application of the HFAC waveform depends on the nerve fiber type, and this property can be used to selectively block specific fiber types. Finally, we examined the recovery time after block induction in unmyelinated nerves and found that recovery from block was dependent on the duration of application of the HFAC waveform. The time-dependent distribution of the recovery time and the non-monotonic threshold behavior in the smaller diameter unmyelinated nerves indicate that multiple mechanisms are involved in block induction using HFAC waveforms, and these mechanisms are dependent not only on the blocking stimulus but also on the characteristics of the nerve fiber. Overall, this work demonstrates that HFAC waveforms may enable inherent peripheral nerve properties to be exploited for potential clinical applications related to the treatment of unwanted neural activity.

Spinal cord injuries (SCI) sever communication between supraspinal centers and the central pattern generator (CPG) responsible for locomotion. Because the CPG is intact and retains the ability to initiate locomotor activity, it can be accessed electrically and pharmacologically. The goal of this thesis was to identify and characterize a novel spinal cord surface site along the sacral dorsal column (sDC) for electrically evoking locomotor-like activity in the neonatal rat spinal cord. Stimulation of the sDC robustly activated rhythmic left-right alternation in flexor-related ventral roots that was dependent on the activation of high-threshold C fiber afferents. The C fibers synapsed onto spinal neurons, which project to the lumbar segments as part of a pathway dependent on purinergic, adrenergic, and cholinergic receptor activation. In ventral roots containing only somatic efferents, rhythmic activity was rarely recruited. However, in ventral roots containing both autonomic and somatic efferents, sacral dorsal column stimulation recruited autonomic efferent rhythms, which subsequently recruited somatic efferent motor rhythms. The efferent rhythms revealed a half-center organization with very low stimulation frequencies, and the evoked alternating bursts entrained to the stimuli. Similar entrainment was seen when sDC stimuli were applied during ongoing neurochemically-induced locomotor rhythms. The rhythmic patterns evoked by sDC stimulation operated over a limited frequency range, with a discrete burst structure of fast-onset, frequency-independent peaks. In comparison, neurochemically-induced locomotor bursts operated over a wide frequency range and had slower time to peaks that varied with burst frequency. The overall findings support the discovery of an autonomic efferent pattern generator that is recruited by sacral visceral C fiber afferents. It is hoped that this research will advance the understanding of afferent activation of the lumbar central pattern generator and potentially provide insight useful for future development and design of neuroprosthetic devices.

Functional electrical stimulation (FES) devices have direct applications in the realm of rehabilitation engineering, physiotherapy, occupational therapy and medicine for research, diagnostic and therapeutic purposes. This thesis presents a novel electrical stimulator for use in a FES system. The stimulator produces regulated current pulses using two switched mode power supplies (SMPS) in series. The first power stage - a flyback converter - steps up the supply voltage using primary side digital control. The second power stage is a buck converter with output current hysteretic control. An output switched capacitor circuit shapes the current pulses. All pulse variables are programmable and various pulses can be formed for virtually any FES application. Compared to previous FES devices, the pulses generated here are sharper, have faster rise time and the amplitude and temporal characteristics are more tightly regulated. A single channel prototype system is implemented and experimental results are shown.

Functional electrical stimulation (FES) devices have direct applications in the realm of rehabilitation engineering, physiotherapy, occupational therapy and medicine for research, diagnostic and therapeutic purposes. This thesis presents a novel electrical stimulator for use in a FES system. The stimulator produces regulated current pulses using two switched mode power supplies (SMPS) in series. The first power stage - a flyback converter - steps up the supply voltage using primary side digital control. The second power stage is a buck converter with output current hysteretic control. An output switched capacitor circuit shapes the current pulses. All pulse variables are programmable and various pulses can be formed for virtually any FES application. Compared to previous FES devices, the pulses generated here are sharper, have faster rise time and the amplitude and temporal characteristics are more tightly regulated. A single channel prototype system is implemented and experimental results are shown.

The level and completeness of spinal cord injury (SCI) above the first lumbar vertebra determine the degree of multi-system impairments including altered respiratory function and decreased capacity to maintain upright posture and seated postural stability in humans. Both systems were studied in able-bodied (AB) subjects and individuals with tetraplegia to explore the potential of functional electrical stimulation (FES) as a neuroprosthesis for seated postural control without compromising respiratory function. Data for AB participants (n=10) indicated higher tidal volumes, greater trunk extensor muscle activity, and different values of seated postural stability in upright sitting compared to slouch sitting. In three case studies of individuals with tetraplegia, surface FES was applied to trunk muscles. Changes in tidal volume, respiratory rate, and seated postural stability were case specific. These studies inform the development of a strategy for non-invasive FES as a neuroprosthesis for sitting balance while preserving respiratory function in individuals with SCI.

The level and completeness of spinal cord injury (SCI) above the first lumbar vertebra determine the degree of multi-system impairments including altered respiratory function and decreased capacity to maintain upright posture and seated postural stability in humans. Both systems were studied in able-bodied (AB) subjects and individuals with tetraplegia to explore the potential of functional electrical stimulation (FES) as a neuroprosthesis for seated postural control without compromising respiratory function. Data for AB participants (n=10) indicated higher tidal volumes, greater trunk extensor muscle activity, and different values of seated postural stability in upright sitting compared to slouch sitting. In three case studies of individuals with tetraplegia, surface FES was applied to trunk muscles. Changes in tidal volume, respiratory rate, and seated postural stability were case specific. These studies inform the development of a strategy for non-invasive FES as a neuroprosthesis for sitting balance while preserving respiratory function in individuals with SCI.