Reconocimiento de tres patrones básicos de movimiento de la mano utilizando electromiografía de superficie y algoritmos inteligentes / Identification of three basic hand movement patterns by surface electromyography and smart algorithms

Introducción: este artículo presenta la predicción de tres tipos de movimientos básicos de la mano mediante un algoritmo inteligente para extraer características imprescindibles para el reconocimiento de patrones de movimiento a partir del análisis de señales electromiográficas superficiales adquiridas con el dispositivo Myo. Objetivo: reconocer y predecir patrones básicos de movimiento de la articulación del brazo utilizando electromiografía de superficie para aplicarlo sobre un prototipo de prótesis. Métodos: se tomaron datos de 13 estudiantes de 22 y 23 años de la Universidad Politécnica Salesiana, cada uno de los cuales ejecutó tres tipos de agarre: cilíndrico, pinza y pinza planar. Se trabajó con una frecuencia de 10 Hz y se tomaron 5 muestras por tipo de agarre durante 60 segundos. Para el análisis estadístico de los datos se utilizó la herramienta Anova, estableciendo un valor de significancia mayor a 0,65. Resultados: En ciertos voluntarios hay una mayor reacción en el electrodo 1 debido a que su antebrazo es mayor. El tiempo de respuesta para el reconocimiento varía dependiendo del número de variables que se tenga que comparar. Cuando se analiza un solo movimiento es de 2,6 segundos, en cambio, cuando se analizan los 3 movimientos el tiempo de respuesta incrementa a 7,8 segundos por la cantidad de electrodos que se quieran analizar. Conclusiones: la respuesta del sistema propuesto empieza a ser más lenta a medida que se analizan más movimientos a la vez y por tanto, es menos efectiva. El tiempo de ejecución y respuesta de nuestro sistema, en comparación al estado del arte, es más alto, debido a que se utilizan menos métodos de caracterización de la señal. Adicionalemtne, una limitante del proyecto es la frecuencia de muestreo del dispositivo Myo (200Hz)(AU)

Introduction: the paper presents the prediction of three basic hand movement types by means of a smart algorithm to draw characteristics indispensable for identification of movement patterns based on the analysis of surface electromyographic signals obtained with the Myo device. Objective: recognize and predict basic movement patterns of the arm joint using surface electromyography with a view to applying them over a prosthesis prototype. Methods: data were taken from 13 students aged 22 and 23 years from the Salesian Polytechnic University, each of whom performed three types of grasp: cylindrical, pincer and palmar pincer. A 10 Hz frequency was used and 5 samples were taken of each grasp type during 60 seconds. Statistical analysis was performed with the tool ANOVA, establishing a significance value > 0.65. Results: in certain volunteers a greater reaction was observed in electrode 1, due to their larger forearms. Response time for identification varies with the number of variables to be compared. When only one movement is analyzed, response time is 2.6 seconds, but when the three movements are examined it rises to 7.8 seconds by the number of electrodes intended to be studied. Conclusions: the response of the system proposed starts to slow down as more movements are analyzed simultaneously, which makes it less effective. The performance and response time of our system is higher than in state-of-the-art systems, since fewer signal characterization methods are used. On the other hand, a limitation of the project is the sampling frequency of the Myo device (200 Hz)(AU)

Estimación en la Intención de Agarres: Cilíndrico, Esférico y Gancho Utilizando Redes Neuronales Profundas / Estimation of Hand-Grip Intention: Cylindrical, Spherical and Hook Using Deep Neural Networks

Resumen Las amputaciones de extremidades superiores pueden producir diversos grados de incapacidad en la persona afectada, esto es exacerbado aún más, si se presenta durante un periodo de su vida laboral activa, por esta razón es de importancia social el estudio de las prótesis y algoritmos que ayuden a un mejor control de estas por parte del usuario. En esta investigación, se propone una arquitectura basada en redes neuronales recurrentes del tipo Long Short-Term Memory y redes convolucionales para la clasificación de señales electromiográficas, con aplicaciones para control de prótesis de mano. La red propuesta clasifica tres tipos de agarres realizados con la mano: cilíndrico, esférico y de gancho. El modelo propuesto al ser evaluado mostró una eficiencia (accuracy) del 89 %, en contraste con una red neuronal artificial basada en capas completamente conectadas que solo obtuvo una eficiencia del 80% en la predicción de los agarres. El presente trabajo se limita solamente a evaluar la red ante una entrada de electromiograma y no se implementó un sistema de control para la prótesis de la mano. Así, una arquitectura de redes convolucionales para el control de prótesis de mano que pueden ser entrenadas con las señales del sujeto.

Abstract Upper extremities amputations can produce different disability degrees in the amputated person, this is acerbated even more, when it happens during active working life. So, for this reason, it is of social importance the study of prostheses and algorithms that help a better control of these by the user. In this research, we propose an architecture based on recurrent neural networks, called Long Short-Term Memory, and convolutional neural networks for classification of electromyographic signals, with applications for hand prosthesis control. The proposed network classifies three types of movements made by the hand: cylindrical, spherical and hook grips. The proposed model showed an efficiency (accuracy) of 89%, in contrast to an artificial neural network based on completely connected layers that only obtained an efficiency of 80% in the prediction of the hand movements. The present work is limited to evaluate the network with an electromyogram input, the control system for hand prosthesis was not implemented. Thus, an architecture of convolutional networks for the control of hand prostheses that can be trained with the signals of the subject.

Rapid Imaging: Recent Advances in Abdominal MRI for Reducing Acquisition Time and Its Clinical Applications

Magnetic resonance imaging (MRI) plays an important role in abdominal imaging. The high contrast resolution offered by MRI provides better lesion detection and its capacity to provide multiparametric images facilitates lesion characterization more effectively than computed tomography. However, the relatively long acquisition time of MRI often detrimentally affects the image quality and limits its accessibility. Recent developments have addressed these drawbacks. Specifically, multiphasic acquisition of contrast-enhanced MRI, free-breathing dynamic MRI using compressed sensing technique, simultaneous multi-slice acquisition for diffusion-weighted imaging, and breath-hold three-dimensional magnetic resonance cholangiopancreatography are recent notable advances in this field. This review explores the aforementioned state-of-the-art techniques by focusing on their clinical applications and potential benefits, as well as their likely future direction.

Advanced Methods in Dynamic Contrast Enhanced Arterial Phase Imaging of the Liver

Dynamic contrast enhanced (DCE) magnetic resonance (MR) imaging plays an important role in non-invasive detection and characterization of primary and metastatic lesions in the liver. Recently, efforts have been made to improve spatial and temporal resolution of DCE liver MRI for arterial phase imaging. Review of recent publications related to arterial phase imaging of the liver indicates that there exist primarily two approaches: breath-hold and free-breathing. For breath-hold imaging, acquiring multiple arterial phase images in a breath-hold is the preferred approach over conventional single-phase imaging. For free-breathing imaging, a combination of three-dimensional (3D) stack-of-stars golden-angle sampling and compressed sensing parallel imaging reconstruction is one of emerging techniques. Self-gating can be used to decrease respiratory motion artifact. This article introduces recent MRI technologies relevant to hepatic arterial phase imaging, including differential subsampling with Cartesian ordering (DISCO), golden-angle radial sparse parallel (GRASP), and X-D GRASP. This article also describes techniques related to dynamic 3D image reconstruction of the liver from golden-angle stack-of-stars data.

A compact-sized surface EMG sensor for myoelectric hand prosthesis

Myoelectric prosthesis requires a sensor that can reliably capture surface electromyography (sEMG) signal from amputees for its controlled operation. The main problems with the presently available EMG devices are their extremely high cost, large response time, noise susceptibility, less amplitude sensitivity, and larger size. This paper proposes a compact and affordable EMG sensor for the prosthetic application. The sensor consists of an electrode interface, signal conditioning unit, and power supply unit all encased in a single package. The performance of dry electrodes employed in the skin interface was compared with the conventional Ag/AgCl electrodes, and the results were found satisfactory. The envelope detection technique in the sensor based on the tuned RC parameters enables the generation of smooth, faster, and repeatable EMG envelope irrespective of signal strength and subject variability. The output performance of the developed sensor was compared with commercial EMG sensor regarding signal-to-noise ratio, sensitivity, and response time. To perform this, EMG data with both devices were recorded for 10 subjects (3 amputees and 7 healthy subjects). The results showed 1.4 times greater SNR values and 45% higher sensitivity of the developed sensor than the commercial EMG sensor. Also, the proposed sensor was 57% faster than the commercial sensor in producing the output response. The sEMG sensor was further tested on amputees to control the operation of a self-designed 3D printed prosthetic hand. With proportional control scheme, the myoelectric hand setup was able to provide quicker and delicate grasping of objects as per the strength of the EMG signal.

Consciousness in Piaget: possibilities of understanding

Abstract The objective of this article is to analyze the understanding of the concept of consciousness in Piaget. The theme of consciousness is a key concept in Piaget's theory and he is one of the few psychologists to offer a theoretical structure for the understanding of this theme. Notwithstanding, his proposal for understanding consciousness has been little approached or discussed. Grasp of consciousness, for Piaget, can be understood as the cognitive process of assimilating one's own functioning or that of the other when interacting with physical objects, people, and oneself. The process of constructing grasp of consciousness is explained by meaningful implication, reflecting abstraction, and equilibration. The dialectics between body and mind and between causality and implication pervade the discussions on consciousness in Piaget's work. Consensus is not found in the literature with regard to Piaget's conception of consciousness in virtue of this theme being dealt with at different times in his works with slightly distinct approaches. His works following the 1960s offer new possibilities of understanding the concept of consciousness. Although Piaget moved on in his formulations about consciousness, the essence of his ideas can already be found in his early works.

Grasp torque control based on experiential learning and haptic feedback / 医疗卫生装备

Objective To propose a grasp torque control based on experimental learning and haptic feedback to facilitate the manipulator in dexterous manipulation.Methods An experience database was built firstly,and then the object was recognized by tactile feedback in the grasp task.If the object had been experitentially grasped,the torque was output based on the database.In case a new object was grasped,the optimal output torque was calculated by iterative learning.Results The experiment showed that the robot hand could find the experiential output torque quickly when encountering the object in database and calculate the torque by iterative learning to achieve grasp task.Conclusion The experiential database grows up when the robot hand learns more and more experience.It can fast output torque like human in the grasp task.

Novel Information on Anatomic Factors Causing Grasp Reflex in Frontal Lobe Infarction: A Case Report

We report a patient with a severe limitation of function in the right hand resulting from grasp reflex following a stroke affecting the left anterior cerebral artery region. We describe, using diffusion tensor tractography (DTT), a disconnection between the bilateral frontal lobes via the corpus callosum. The patient could not control his right hand at all, even though his bilateral corticospinal tracts were intact. We noted that over the infarcted lesion on DTT, the white matter was invisible from the corpus callosum to the prefrontal cortex. These findings reflected a unique pattern of white-matter disconnection between the ipsilateral medial frontal lobe and ipsilateral and contralateral frontal cortex causing hand function deterioration in the form of severe grasp reflex.

Tamanho e rigidez dos objetos influenciam os ajustes proximais e distais do alcance de crianças? / Can size and rigidity of objects influence infant's proximal and distal adjustments of reaching?

CONTEXTUALIZAÇÃO: Objetos influenciam nos ajustes do alcance de lactentes, no entanto ainda não se investigou se esses ajustes se modificam em crianças com mais idade. OBJETIVOS: Verificar se o tamanho e a rigidez dos objetos influenciam os ajustes proximais e distais do alcance dos 6 aos 8 meses e aos 36 meses de idade. MÉTODOS: A nove crianças saudáveis foram apresentados: um objeto rígido grande, um rígido pequeno, um maleável grande e um maleável pequeno. Os alcances foram filmados e posteriormente analisados qualitativamente quanto aos ajustes proximais (alcance uni e bimanual) e distais (orientação da mão horizontalizada, verticalizada e oblíqua; mão aberta, semiaberta e fechada) e a preensão desses objetos (com e sem). Foram aplicados o Teste de Friedman e as comparações múltiplas de Dunn, considerando-se 0,05 como diferença significativa. RESULTADOS: Constatou-se que, aos 36 meses, houve mais alcances unimanuais do que nas idades anteriores e, em todas as idades, os alcances unimanuais foram realizados principalmente para os objetos pequenos. Aos 36 meses, as crianças orientaram a mão horizontalizada para tocar e apreender os objetos, enquanto que, aos 6 e 7 meses, a orientação foi oblíqua para tocar e verticalizada para apreendê-los, independentemente das propriedades dos objetos. No decorrer dos meses, tanto no início quanto no final do alcance, as mãos tornaram-se mais abertas, principalmente para tocar o objeto rígido grande, e as crianças realizaram cada vez mais alcances com preensão, principalmente para os objetos maleáveis ou objetos pequenos. CONCLUSÕES: De 6 a 36 meses, os alcances tornaram-se mais refinados e ajustados às propriedades mais discrepantes dos objetos apresentados, o que se observou pelas modificações nos ajustes proximais e distais.

BACKGROUND: It has been found that objects influence the adjustments to reaching of breastfeeding infants, however, it has not been investigated whether these adjustments change in older infants. OBJECTIVES: The aim of this study was to determine whether the size and rigidity of objects influence the proximal and distal adjustments to reaching of infants of 6, 7, 8 and 36 months of age. METHODS: Nine healthy infants were presented with: one large rigid, one small rigid, one large malleable and one small malleable object. The movements were videotaped and later analyzed qualitatively with regard to proximal (unimanual and bimanual reaching) and distal adjustments (horizontal, vertical and oblique hand orientation, opened, half-open and closed hand) and with regard to grasping of these objects (with and without). Friedman test and Dunn multiple comparisons were applied and 0.05 was considered as a significant difference. RESULTS: Infants of 36 months of age performed more unimanual reaching than younger infants. Additionally, at all ages, unimanual reaching was particularly performed for small objects. At 36 months of age infants guided the hand horizontally to touch and grasp the objects, while at 6 and 7 months the hand orientation was oblique to touch and vertical to grasp the objects, regardless of the object's properties. Over the months, both at the beginning and at the end of reaching, the hands became more open, especially to touch the large rigid object, and infants increasingly performed reaching with successful grasping, especially for malleable or small objects. CONCLUSIONS: From 6 to 36 months of age, the reaching became more refined and the infants adjusted to the different properties of the objects which were observed through changes in the proximal and distal adjustments.

Equilibração e tomada de consciência: análise do jogo Cara a Cara / Equilibration and grasp of consciousness: an analysis of the game

O objetivo deste estudo é demonstrar teoricamente a viabilidade da utilização do jogo Cara a Cara para o estudo dos seguintes processos de desenvolvimento: equilibração e tomada de consciência, próprios do referencial piagetiano. O processo de construção do conhecimento passa, inclusive, pela interação sujeito/objeto e observáveis/coordenações, que são pares dialéticos envolvidos na adaptação do sujeito ao meio. Ao ter suas estruturas cognitivas desequilibradas, o sujeito precisa tentar compreender suas estratégias e as características do objeto. Fazendo isso, caminha para tomadas de consciências mais centrais, até o ponto em que consegue resolver a questão e, por algum tempo, manter suas estruturas equilibradas. O jogo Cara a Cara, conforme demonstrado ao longo desta discussão, se apresenta como um instrumento adequado para o entendimento de processos de construção do conhecimento, na medida em que permite a observação e o relato verbal acerca do que o sujeito compreende de si e do jogo.

The goal of this study is to demonstrate theoretically the utilization viability of the game ôGuess Who?õ for the study of the following development processes: equilibration and grasp of consciousness, particular of the piagetian referential. The knowledge construction process passes, besides, by the interaction subject/object and observable/coordinations, which are dialectic pairs involved in the subject adaptation to the environment. By having unbalanced cognitive structures, the subject must try to comprehend his/her strategies and the characteristics of the object. By doing so, he walks to more central grasps of consciousness to the point in which he/she can solve the issue and for some time, maintain their structure balanced. The game ôGuess Who?õ, as demonstrated throughout this discussion is presented as an appropriate tool for understanding processes of knowledge construction, in that it enables the observation and verbal report about what the subject understands of himself/herself and the game.

Early Objectified Detection Method of Sensorineural Component in Hand Arm Vibration Syndrome / 대한산업의학회지

OBJECTIVES: In order to determine find out the best methods for a more objective detection of neurologic abnormality in early hand arm vibration syndrome(HAVS), early with analyzing the validity of each of the detection methods was analyzed. We evaluated the relationships between the sensorineural stage of Stockholm-revised vibration syndrome classification and the results of several tests. METHODS: 497 workers were investigated for symptom, exposure duration, the types of tools used, and medical history from January 2000 to December 2007. Pain sense threshold, vibrotactile threshold, hand grasp force, finger grasp force, and a finger tapping frequency test were performed by the workers. RESULTS: The grinder(67.3%) was the most commonly used tool and the mean exposure duration was 14.8 years. Although the pain sense and vibrotactile threshold level tended to increase according to sensorineural stage of the Stockholm classification, there was statistically significant difference in the vibrotactile threshold of 125, 250 Hz (p=0.006~0.038) but not in the pain sense threshold. Hand and finger grasp force tended to decrease according to the sensorineural stage of Stockholm classification and there was statistically significant difference(p=0.041,<0.001, 0.034) only on the right hand side. The tapping frequency also generally decreased according to the sensorineural stage of the Stockholm classification and there was statistically significant difference (p=0.002~0.019) only on the left hand side. CONCLUSIONS: Although there is no single standardized method that can objectively diagnose the sensorineural component of early HAVS early, the combination of subjective symptoms, the sensorineural stage of Stockholm classification, the pain and vibrotactile threshold test, the hand and finger grasp force, and the finger agility (tapping) test can objectively detect sensorineural component of HAVS early.

Early Objectified Detection Method of Sensorineural Component in Hand Arm Vibration Syndrome / 대한산업의학회지

OBJECTIVES: In order to determine find out the best methods for a more objective detection of neurologic abnormality in early hand arm vibration syndrome(HAVS), early with analyzing the validity of each of the detection methods was analyzed. We evaluated the relationships between the sensorineural stage of Stockholm-revised vibration syndrome classification and the results of several tests. METHODS: 497 workers were investigated for symptom, exposure duration, the types of tools used, and medical history from January 2000 to December 2007. Pain sense threshold, vibrotactile threshold, hand grasp force, finger grasp force, and a finger tapping frequency test were performed by the workers. RESULTS: The grinder(67.3%) was the most commonly used tool and the mean exposure duration was 14.8 years. Although the pain sense and vibrotactile threshold level tended to increase according to sensorineural stage of the Stockholm classification, there was statistically significant difference in the vibrotactile threshold of 125, 250 Hz (p=0.006~0.038) but not in the pain sense threshold. Hand and finger grasp force tended to decrease according to the sensorineural stage of Stockholm classification and there was statistically significant difference(p=0.041,<0.001, 0.034) only on the right hand side. The tapping frequency also generally decreased according to the sensorineural stage of the Stockholm classification and there was statistically significant difference (p=0.002~0.019) only on the left hand side. CONCLUSIONS: Although there is no single standardized method that can objectively diagnose the sensorineural component of early HAVS early, the combination of subjective symptoms, the sensorineural stage of Stockholm classification, the pain and vibrotactile threshold test, the hand and finger grasp force, and the finger agility (tapping) test can objectively detect sensorineural component of HAVS early.

Força de preensão palmar em crianças e adolescentes saudáveis: [revisão] / Hand strength in healthy children and teenagers: [review]

OBJETIVO: Revisão de literatura sobre força de preensão palmar em crianças e adolescentes saudáveis na faixa etária de quatro a 18 anos de idade. FONTES DE DADOS: Medline, Lilacs e SciELO, no período de 2000 a 2007, utilizando-se as palavras-chave: aperto, mão, força, preensão, criança e adolescente. SÍNTESE DOS DADOS: A importância da mensuração da força de preensão é fornecer um índice objetivo da integridade funcional dos membros superiores. Estudos avaliando a força da preensão palmar vêm sendo descritos desde 1956, porém a maioria dos artigos engloba a população adulta (19 a 44 anos) e adulta média (45 a 64 anos). Somente um artigo foi publicado no Brasil a respeito da força de crianças e adolescentes. Os trabalhos relatados correlacionam a força de preensão palmar e variáveis antropométricas. CONCLUSÕES: Estudos com delineamento adequado e amostras representativas são necessários para avaliar a força da preensão em crianças e adolescentes no Brasil. Observou-se que os meninos têm força de preensão palmar maior que as meninas, principalmente após 11 anos de idade. Os fatores antropométricos como peso e altura foram os que mais significantemente se associaram à força de preensão palmar.

OBJECTIVE: To review the literature regarding hand grip strength in healthy children and teenagers with four to 18 years old. DATA SOURCES: Databases Medline, Lilacs and SciELO were searched for studies published from 2000 to 2007, using the keywords: grasp, hand, strength, grip, child and adolescent. DATA SYNTHESIS: Measures of hand grip strength are important to provide an objective index of the functional integrity of the upper limbs. Studies evaluating the hand grip strength have been published since 1956, however the majority of them enrolled adults (19 to 44 years-old) and middle-age (45 to 64 years-old) subjects. Only one article was published in Brazil about hand grip strength of children and teenagers. Most studies try to associate hand grip strength and anthropometric variables. CONCLUSIONS: Prospective randomized trials with large number of patients are needed to evaluate the hand grip strength in Brazilian children and teenagers. Boys have hand grip strength greater than girls, especially after 11 years old. The anthropometric factors such as weight and height were significantly associated with hand grip strength.

Effects of grasp seed procyanidins(原青花素) on acute lung injury and renal function damage in rats / 中国中西医结合急救杂志

Objective: To investigate the effects of grasp seed procyanidins(GSP,原青花素) on lipopolysaccharide(LPS)induced acute lung injury(ALI) in rats with renal function damage and the related possible molecular mechanisms.Methods: The homogenates of lung and kidney were prepared and venous blood were collected at 6 hours after injection of LPS and medicine.The changes of contents of creatinine(Cr),blood urea nitrogen(BUN),lactic acid(Lac) and nitric oxide(NO) in the blood were measured.The enzyme linked immunosorbent assay(ELISA) was used to measure the levels of tumor necrosis factor?(TNF-?),interleukin-1?(IL-1?),monocyte chemoattractant protein-1(MCP-1) and IL-6 in the serum,lung and renal cortex tissue homogenate in various groups.The histopathological changes of lung tissues were observed.The pulmonary vascular permeability and the lung wet/dry(W/D) weight ratio were determined;the malonaldehyde(MDA) content,Na+K+-ATPase,superoxide dismutase(SOD),myeloperoxidase(MPO) and glutathion peroxidase(GSH-Px) activities in lung and renal tissues were also determined.Changes of mitogen activated protein kinase(MAPKs) were detected by Western blotting,and the combination activity of nuclear factor-?B(NF-?B) to DNA was detected by electrophoretic mobility shift assay (EMSA) in lung tissues.Results: ①Compared with the normal rats in control group,the lungs of the rats in LPS treatment group and GSP group had significant hyperemia and spotted hemorrhage.The inflammatory granulocyte infiltration,diffuse alveolar septum thickening and spotted hemorrhage were observed in the pathological examinations,while in LPS plus GSP group the above mentioned pathological changes were milder.②Compared with control group,the lung W/D and pulmonary vascular permeability were much higher in the LPS treatment groups(P

Effects of grasp seed procyanidins on homocysteine-induced proliferation and migration in vascular smooth muscle cells / 中国病理生理杂志

AIM:To investigate the effects of grasp seed procyanidins(GSP) on homocysteine-induced proliferation and migration in vascular smooth muscle cells(VSMC) and related molecular mechanisms.METHODS: Cell count and -TdR assay were used for detecting cell proliferation and DNA synthesis,ELISA assay was used for detecting inflammatory response,DCFH-DA assay for examining the levels of reactive oxygen species(ROS),Western blotting for detecting protein expression.RESULTS: Homocysteine(0.1-1 mmol/L) increased VSMC proliferation and migration,and the levels of ROS were in a dose-dependent manner.The results of Western blotting showed that homocysteine significantly increased the expression of MCP-1,IL-6 and TNF-?.However,Compared with control group,in GSP(5-20 g/L) group,the increased VSMC proliferation,migration and the production of ROS and the expression of MCP-1,IL-6 and TNF-? mediated by homocysteine were markedly suppressed.EMSA showed that in GSP treatment group,the NF-?B activation was also almost completely inhibited.CONCLUSION: GSP inhibits homocysteine-induced VSMC proliferation,migration and inflammatory response through interfering with ROS dependent on NF-?B signal pathway.