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A perda do controle motor é uma das mais debilitantes consequências da lesão medular espinhal. A interrupção parcial ou completa das vias ascendentes sensoriais e vias descendentes motoras tornam o indivíduo incapaz de caminhar e realizar atividades de maneira funcional. A ocorrência da reorganização cortical sensório-motora espontânea imediatamente após a lesão e continuamente ao longo do tempo pode ocorrer em áreas específicas, bem como em todo córtex cerebral, evidenciado em estudos prévios com uso de exames de imagem. Entender a complexa interação entre alterações anatômicas, funcionalidade e reorganização cortical induzidas pela lesão medular, bem como definir seus efeitos, é crucial para avaliação das terapias de reabilitação e consequente melhora na qualidade de vida do sujeito. Neste estudo, imagens de Ressonância Magnética foram obtidas para explorar alterações morfológicas na Substância Cinzenta (SC) e Substância Branca (SB) no córtex cerebral de indivíduos com lesão medular torácica. Dois grupos de voluntários foram recrutados para esta pesquisa (portadores de lesão medular - Grupo Experimental; e não-lesionados – Grupo Controle). A comparação intergrupos foi realizada considerando ainda o tempo pós-lesão. A avaliação global do encéfalo não detectou alteração no volume da SC total. Diferenças volumétricas na SC cortical foram verificadas no giro pré-central e no sulco pré-central inferior. A alteração observada no giro pré-central ocorreu no hemisfério esquerdo, responsável pelo controle motor do membro inferior direito, compatível com a dominância dos voluntários de ambos os grupos (destros). Os achados fornecem evidências de que o tempo pós-lesão não influenciou em maior perda volumétrica global significativa. No entanto, alterações em regiões específicas, associadas ao controle motor de regiões abaixo da lesão, foram evidenciadas neste estudo.

Amputation is a traumatic process where the person needs to start rehabilitation immediately to regain physical independence. Traditionally, rehabilitation periods last up to 12 months and have dropout rates above 35%. Initiatives to train amputees through Augmented Reality (AR) can provide more realistic and immersive experiences. This project presents a Markerless RA application for the rehabilitation of upper limb amputees. The Cylindrical Socket tracking happens in real-time through the VIVE Tracker. The application is evolving excitingly.

Moving a finger around the boundary edge is one of the important strategies followed by humans for ascertaining the shape and size of an object by touch. Tactile response from thousands of mechanoreceptors in the human hand offers a high spatiotemporal resolution to perceive the edge orientation quickly ( 50 ms) and accurately (acuity of 3 ° ). Inspired by the computational efficiency of biological tactile system, we present a neuromorphic approach to artificial tactile sensing that mimics the spike-based spatiotemporal tactile response of Fast Adapting type I (FA-I) mechanoreceptors. We propose a novel, model-based spatiotemporal correlation matching method to estimate the orientation of the boundary edge while a piezoresistive tactile sensor array attached to robotic arm palpates over the object. Results highlight the ability of the proposed method to efficiently leverage spatial and temporal information, by obtaining very precise orientation estimates ( ± 1.67° error for edges oriented from 10° to 90°, with a step of 5°) in spite of a low-resolution sensor (169 mm2, 4 × 4 resolution). A comparison with both spatial and spatiotemporal based classifiers indicates that the proposed method achieves 20 % lower mean absolute error (MAE) than its closest counterparts, all of which required supervised training. Furthermore, we show that even with a ten-fold loss of spike time precision (1 ms–10 ms), MAE is maintained at 2°. This work highlights that even with a modest sensor size and resolution, spatiotemporal similarity metrics can be used to obtain very precise estimates of orientation. Such an approach has potential applications towards improving the tactile sensing capability in robotic/prosthetic hands where knowledge of spatial edge orientation information is paramount for object manipulation, and sensor contact area is often sparse and small.

Spinal cord injury (SCI) leads to a general lack of sensory and motor functions below the level of injury and may promote deafferentation-induced brain reorganization. Functional magnetic resonance imaging (fMRI) has been established as an essential tool in neuroscience research and can precisely map the spatiotemporal distribution of brain activity. Task-based fMRI experiments associated with the tongue, upper limbs, or lower limbs have been used as the primary paradigms to study brain reorganization following SCI. A review of the current literature on the subject shows one common trait: while most articles agree that brain networks are usually preserved after SCI, and that is not the case as some articles describe possible alterations in brain activation after the lesion. There is no consensus if those alterations indeed occur. In articles that show alterations, there is no agreement if they are transient or permanent. Besides, there is no consensus on which areas are most prone to activation changes, or on the intensity and direction (increase vs. decrease) of those possible changes. In this article, we present a critical review of the literature and trace possible reasons for those contradictory findings on brain reorganization following SCI. fMRI studies based on the ankle dorsiflexion, upper-limb, and tongue paradigms are used as case studies for the analyses.

Robotic manipulators face significant challenges when handling objects of different sizes and shapes. Incorporating a sense of touch into these devices has the potential to improve performance and dexterity. In this paper, a bio-inspired approach is presented for slip detection and suppression during object manipulation. The method was inspired by the behavior of FA-I afferents located in the glabrous skin that encode sliding motion of objects over the skin. The proposed slip detection method encodes object motion captured by a slip sensor into spikes, following principles of neuromorphic sensing. The spikes are used as the feedback signal for an event-based closed-loop control system. The controller behaves in a reflex-like manner and actively engages the robotic fingers to increase grip force and suppress slip. A Dynamic Adaptive Threshold method was designed to improve slip detection for different surface properties of grasped objects. The performance of the method was evaluated following situations of dynamic slip caused by a sudden or gradual increase in object weight. The results demonstrated the feasibility of the proposed method. Slip events were suppressed before complete object slippage in 80% of all experimental trials. The response time ( Delta {\text {t}} < 85$ ms) was compatible with the time for grip force adjustments in humans. This paper explored event-based touch applicable to the problem of manipulation, which is less explored than event-based tactile perception and shows promising prospects for both robotics and prosthetics. - 2001-2012 IEEE. Scopus

Amputation is a lasting life experience. Furthermore, prosthesis fitting and training are usually long and sometimes frustrating experiences. Few approaches explore the problem of controlling virtual myoelectric prostheses, since integration with current VR devices is not a trivial issue. Besides, the lack of proper sensory feedback often leads to an experience far too ‘artificial’ for most users. In this work, we propose a system that uses Immersive Virtual Reality (IVR) and EMG signal processing to provide a training environment for amputees who are supposed to use myoelectric prostheses. Here, we also investigate the efficiency of learning how to control a virtual prosthesis with and without sensory feedback. The system runs on a Vive Pro System using a Vive Tracker to track the user’s arm position and orientation and mirror the movement into a virtual prosthesis. EMG signals control the opening and closing of a virtual prosthesis. Vibrational elements placed on the user’s forearm provide sensory feedback.Our results show that virtual training can be significantly improved when proper tactile feedback is provided, especially for myoelectric controlled system. EMG control and tactile feedback have provided an effective control loop, which allows for a better sense of realism for the training protocol.

This work presents a Virtual Reality training environment for upper limb amputees. Based on principles of a serious game, the training environment aims to teach the patient how to control a virtual prosthesis, that lately, will be printed and attached to his forearm. Using a tether with different sensors the patient can interact with the virtual environment. The training protocols were provided by health-care professionals and the interaction technology was developed under their supervision, to ensure high levels of mobility and comfort for the user that are attached to the remaining forearm of the amputee. It was applied a questionnaire that evaluates several points of the game. It was observed that the methods and techniques used for the development of the serious game were shown to be consistent and adequate for the proposed goal.

Stroke is the most common disease that leads to the dexterity impairment of the upper limbs. Serious games have emerged as an advantageous and enjoyable alternative to rehabilitation treatment when compared to traditional therapies. This work presents the development of a customizable serious game, based on Virtual Reality techniques to achieve a more natural and intuitive interface. The game was developed to allow different types of input devices. In so doing, the system consists of a control panel for patient management and customization of the game, a serious game with a realistic environment with levels and adaptive tasks, and a database. The research considered the assistance of physiotherapists to provide protocols that the game followed. Results indicated significant acceptance by the patients, implying the system’s potential use in the post-stroke rehabilitation process of the upper limbs.

The memory reconsolidation hypothesis states that a previously consolidated and stable memory can return to a temporary labile state after retrieved, requiring a new stabilization process. During the labile period, the memory trace is vulnerable to modification, which provides a potential therapeutic opportunity to weaken, updated or strengthen that memory. As such, reconsolidation has been the subject of numerous studies in different domains of human memory that seek strategies to treat post-traumatic disorders and erase or modify pathological memories. A few studies have also investigated the impairment effects of behavioral interferences on motor memory. However, very little has been researched and written about the possibility of using reconsolidation to enhance motor skill learning. Here, we present a critical review of the literature and trace possible applications for human motor memory reconsolidation. We discuss the boundary conditions and the mechanisms to trigger the reconsolidation process, as well as the effects of behavioral interventions in modifying the performance of motor skills.

The most commonly used method for the clinical evaluation of spasticity is the modified Ashworth scale (MAS), which is subjective. In this regard, the spasticity assessment through the tonic stretch reflex threshold, which is an objective method, has emerged as an alternative. It is based on the value of the dynamic stretch reflex threshold, which is measured at different stretch velocities. However, by this definition, it is not possible to define the speed at which passive stretches should be performed during evaluation.This study aimed to evaluate whether the speed-variation sequence used to acquire the dynamic stretch reflex threshold influences the tonic stretch reflex threshold (TSRT) and, consequently, the estimation of spasticity by this method.Three forms of stretching-variation speed were adopted, i.e., increasing, decreasing, and randomised. The study was performed using 10 post-stroke patients.The results showed that the stretch protocols were not all the same and that the method of increasing was most suitable for performing manual passive stretches to evaluate TSRT in these patients. Another analysis was the correlation between MAS and tonic stretch reflex threshold; a weak correlation was observed between the increasing and decreasing methods, and moderate correlation was observed between the random methods. Implications for Rehabilitation We demonstrated that the protocol of execution of passive stretches influences in the measurement of the tonic stretch reflex threshold (TSRT). We recommend the method of increasing velocity for performing manual passive stretches. We also build software with a reliable biological data acquisition system, which makes acquisition and processing of data in real time. In this way, the TSRT is a promising quantitative measure to assess post-stroke spasticity, calculated automatically. We also we provided the use of portable instruments to facilitate the assessment of spasticity in clinical practice.

Several methods have been discussed to assess and quantify proprioceptive deficits. Most clinical assessments are based on categorical or ordinal results which are not sensitive to subtle changes or subtle deficits observed in different patients. In this paper, we propose a quantitative protocol for post-stroke proprioceptive assessment based on three-dimensional inertial tracking. The system is based on a network of five inertial sensors that are attached to the subjects’ upper limbs. Validation of our approach was based on a set of upper-limb experiments performed by thirty healthy subjects and six stroke patients.

Este artigo apresenta uma proposta para desenvolvimento de um sistema sem fio para rastreamento em tempo real da posição dos membros superiores utilizando sensores inerciais. O projeto prevê a utilização de sensores inerciais associados a um microcontrolador de alta performance, que controla os processos de comunicação, aquisição e transmissão de dados. Um transceptor nRF24LE1 é utilizado como link de transmissão sem fio (Rádio Frequência – RF) em alta velocidade. Este projeto tem potencial para aplicação em diversas áreas da engenharia biomédica, provendo mecanismos para uma melhor avaliação biomecânica do movimento humano, bem como pode contribuir para diversas áreas da saúde, como fisioterapia e terapia ocupacional, na avaliação do processo de reabilitação de pacientes pós acidente vascular encefálico., XII SIMPÓSIO DE ENGENHARIA BIOMÉDICA - IX SIMPÓSIO DE INSTRUMENTAÇÃO E IMAGENS MÉDICAS

Prosthesis control through electromyographic signals has been used in many works, but it is still hard to achieve dexterity of a human hand. Current systems rely on the extraction of various features from the EMG signal to further classify user’s intention. In an attempt to contribute to the field, this paper investigates the performance of Multilayer Perceptron and Learning Vector Quantization to classify various classes of movement. Electromyography data were collected from four pairs of electrodes positioned around the forearm of six subjects. Seven classes of movement were classified based on features extracted in the time domain. The results showed that both methods can achieve accuracy above 92%, with a slight advantage for the Multilayer Perceptron - Learning Vector Quantization: 92.69%; Multilayer Perceptron: 94.56%.

Estaapresentação aborda o desenvolvimento de um dispositivo com controle e reabilitação por meio de uma prótese em realidade virtual e aumentada. O indivíduo possuirá a capacidade de controlá-la com sinais eletromiográficos e a partir de dados de localização espacial adquiridos pelo sensor inercial. Assim, o sujeito será capaz de possuir um auto feedback de sua realizações com a possível prótese e gerar menos índices de rejeição com a prótese física.

The spirometry test is usually performed by patients with respiratory diseases, especially chronic patients in hospital environments. Research shows that the difficulty in treatment is due to the distance from patients and specialized health facilities and the delay in care. Therefore, the purpose of this paper is to create an easy-to-use portable spirometer with an intuitive application for conducting examinations with remote monitoring for patients with respiratory diseases, to minimize unnecessary hospitalizations that could have been treated at a distance and try to decrease the lines at hospitals. A portable spirometer and a telemonitoring application were then built and tests were performed to verify the system's operation. The obtained results were satisfactory and the developed system was functional and relevant for the treatment of patients with pulmonary diseases, since there are no similar products in the market that include hardware and software for individual use., XII SIMPÓSIO DE ENGENHARIA BIOMÉDICA - IX SIMPÓSIO DE INSTRUMENTAÇÃO E IMAGENS MÉDICAS

Intensive research in sensors and human-robot interactions has made the social presence of robots safer and more acceptable. In any interaction of the robot with its surroundings, it is important to establish proper contact with the object to ensure complete control over its manipulation. The sense of touch and perception play a vital role to close the feedback loop of contact modulations. This paper discusses the design and development of a novel hybrid sensorized soft-matter structure which has active contact modulation capabilities to ensure better and firm contact in rigid robotic grippers. An integrated multi-taxel piezoresistive tactile sensor which can confer to both rigid and soft surfaces easily was developed as a feedback device. Experimental observations show enhancement in grip and demonstrate a simple slip detection routine under dynamic load condition successfully.

Upper limb amputees lack the valuable tactile sensing that helps provide context about the surrounding environment. Here, we utilize tactile information to provide active touch feedback to a prosthetic hand. First, we developed fingertip tactile sensors for producing biomimetic spiking responses for monitoring contact, release, and slip of an object grasped by a prosthetic hand. We convert the sensor output into pulses, mimicking the rapid and slowly adapting spiking responses of receptor afferents found in the human body. Second, we designed and implemented two neuromimetic event-based algorithms, Compliant Grasping and Slip Prevention , on a prosthesis to create a local closed-loop tactile feedback control system (i.e., tactile information is sent to the prosthesis). Grasping experiments were designed to assess the benefit of this biologically inspired neuromimetic tactile feedback to a prosthesis. Results from able-bodied and amputee subjects show the average number of objects that broke or slipped during grasping decreased by over 50 percent and the average time to complete a grasping task decreased by at least 10 percent for most trials when comparing neuromimetic tactile feedback with no feedback on a prosthesis. Our neuromimetic method of closed-loop tactile sensing is a novel approach to improving the function of upper limb prostheses.

Auditory Brain Machine Interfaces is normally used to support people with severe neurofunctional disabilities. Great part of the auditory interfaces is designed with binary response, presenting to the subject a sequence of deviant and standard tones. Intending to increase the classes of the system, this article aims to study the feasibility of using spatially distributed sounds for enable interfaces with more than two control options. In the tests, the volunteers were exposed to virtualized sounds from the 0°, 60°, 90°, 130° and 180° directions and the electroencephalographic signal (EEG) was measured. Support Vector Machine was employed to classify the different cortical responses resulting from distributed sounds, presenting an average performance of 73.39%. This study confirms that there are significant differences in the auditory evoked potential between stimuli coming from five different locations and that it is possible to use sound virtualization to increase the amount of degrees of classes of a brain machine interface.

Electroencephalography (EEG) inverse problem intends to determine the internal brain signals from EEG electrode signals. Being an ill-posed problem, it needs a regularization function and a regularization parameter (λ). Many techniques have been proposed with different regularization functions, yet all of them still depends on the regularization parameter that can drastically change the solution given its value. In this study we intend to determine if the regularization parameter can be set to a specific value or a smaller interval, and if not, discover what changes in the problem settings causes it to vary. For that we simulated source signals and calculated the signals that these would generate in the EEG electrodes. We then used a genetic algorithm to find the best value of λ applied in different experiments having different regularization functions. Further study is still required, but we could conclude that, for the settings used in this study, different techniques demand different values of λ, and for some experiments with different source signals the value of λ maintained in a smaller interval.

The injection of contrast medium is fundamental for diagnosing and differentiating liver cancers in Computed Tomography (CT). Computer-aided diagnosis systems have been developed to support radiologists in detecting liver lesions. However, the injection of contrast medium may change features and thus affect the automatic segmentation of the liver. In this paper, the performance of an automatic segmentation algorithm using a posteriori information of the liver was compared between the arterial and portal contrast-enhanced CT phases. By performing the liver segmentation with a region growing algorithm based on one-class support vector machines, 28 CT scans in both arterial and portal phases were evaluated. In general, the results show that there were no differences between segmentation performances for both phases. Major segmentation errors were usually related to intrinsic characteristics of the liver. Therefore, based on the results presented in this paper, it was possible to conclude that different contrast-enhanced CT phases do not affect liver segmentation significantly.

Prosthetic devices are capable of restoring motor functions that were lost due to amputations caused by diseases, traumas or injuries. Advanced prosthetic hands are greatly desired since manipulating objects are a great part of daily life. Research have focused on developing enhanced robotic hands with many degrees of freedom and different control mechanisms that makes use of Electromiography (EMG) or Electroencephalography (EEG) signals, for example. Restoring proprioceptive and tactile feedback of prosthetic devices, however, is still a major challenge to the field. Object manipulation consists of complex interactions between the hand and the object and sensory feedback is crucial for proper scaling grip force to avoid slip and excessive force. Therefore, studying how grip forces are adjusted under different conditions can provide insights for developing control schemes that can be added to prosthetic devices in order to make them easier to use and more reliable. In this paper, we investigated how grip force is modulated during pronation and supination movements. We found that changes in force occur in parallel to changes in object orientation, suggesting that it is not a feedback based control scheme where force is adjusted gradually after a change in the orientation is detected. Furthermore, there is a synergism between the forces generated by the thumb and the index finger to maintain grasp stability.

Optimal sensorimotor control is a complex task that is beautifully performed by the Central Nervous System (CNS). A great part of our control scheme is related to our capacity of learning novel skills. Theories of sensorimotor control have proposed the use of internal models by the CNS as a way to improve control when facing uncertainties, perturbations and to overcome slow feedback. In this paper, we investigated the dynamics of learning an internal model of a novel sensorimotor task during trials with and without visual feedback. In order to do so, 5 participants performed a sensorimotor task that translated force into positions of a cursor on the screen. We observed that performance gradually improved during training in both sensory modalities (correlation between learning curves was 0.89). However, the absence of visual feedback is detrimental to performance and somatosensory feedback alone was not sufficient to match performance when visual feedback is available. This suggests that error-signals given in visual coordinates are necessary to calibrate the internal model being learned.

Methods of assessment and monitoring of proprioceptive function have often been discussed. Most clinical proprioceptive evaluations are based on categorical or ordinal results and are not sensitive to changes and subtle deficits. This study aimed to propose a quantitative proprioceptive assessment protocol based on three-dimensional inertial sensors, easily adapted for clinical practice. Eighteen healthy subjects participated in the study, divided into age groups. Five inertial sensors were coupled to the upper limbs, and active movements were made to reach a reference point. The subject was blindfolded and was then instructed to replicate the move with the contralateral limb. We assessed 02 shoulder joint angulations and 02 angles for elbow joint. The results indicated that the equipment can generate quantitative measures more precise than the commonly used clinical tests.