Effective high compression of ECG signals at low level distortion

An effective method for compression of ECG signals, which falls within the transform lossy compression category, is proposed. The transformation is realized by a fast wavelet transform. The effectiveness of the approach, in relation to the simplicity and speed of its implementation, is a consequence of the efficient storage of the outputs of the algorithm which is realized in compressed Hierarchical Data Format. The compression performance is tested on the MIT-BIH Arrhythmia database producing compression results which largely improve upon recently reported benchmarks on the same database. For a distortion corresponding to a percentage root-mean-square difference (PRD) of 0.53, in mean value, the achieved average compression ratio is 23.17 with quality score of 43.93. For a mean value of PRD up to 1.71 the compression ratio increases up to 62.5. The compression of a 30 min record is realized in an average time of 0.14 s. The insignificant delay for the compression process, together with the high compression ratio achieved at low level distortion and the negligible time for the signal recovery, uphold the suitability of the technique for supporting distant clinical health care

Reabilitação pulmonar em pacientes com Doença Pulmonar Obstrutiva Crônica

Introduction. Chronic Obstructive Pulmonary Disease (COPD) is a preventable and treatable condition with permanent respiratory symptoms and progressive restriction of airflow. Pulmonary rehabilitation has shown improvement in physical activity, decrease in dyspnea and respiratory symptoms, in addition to improving quality of life. The aim of this article is to analyze the available scientific evidence on pulmonary rehabilitation in Obstructive Pulmonary Disease. Materials and methods. For the bibliographic search we included articles from the databases PudMed, Jane, Science Direct, Ovid, Medline, Proquest, published in the last five years with updated evidence related to COPD pulmonary rehabilitation. Fifty-three articles of interest in the field were selected and met the inclusion criteria. Results. The selected articles address the topic of pulmonary rehabilitation in COPD, with application of protocols that include respiratory assessment questionnaires. Within the analyzed results, no significant demographic difference between the intervened groups is evident, the incidence of participation is 100 patients for each pulmonary rehabilitation program, the average age was 59 years, and the rehabilitation programs are developed at hospital, community and outpatient level. Conclusions. Implementing pulmonary rehabilitation programs in patients with COPD is a fundamental element in the management of this disease, showing beneficial effects by optimizing symptoms, exercise capacity, control over the disease and improvement in quality of life.Introducción. La enfermedad Pulmonar Obstructiva Crónica (EPOC) se caracteriza por ser una patología prevenible y tratable, que presenta sintomatología respiratoria permanente por restricción progresiva del flujo aéreo. La rehabilitación pulmonar, ha demostrado mejoría en la actividad física, disminución de la disnea y sintomatología respiratoria, además de mejorar la calidad de vida. El objetivo de este artículo es analizar la evidencia científica disponible sobre la rehabilitación pulmonar en la Enfermedad Pulmonar Obstructiva. Materiales y métodos. Para la búsqueda bibliográfica se incluyeron artículos de las bases de datos PudMed, Jane, Science Direct, Ovid, Medline, Proquest, publicados en los últimos cinco años con evidencia actualizada en relación a la rehabilitación pulmonar EPOC. Se seleccionaron 53 artículos de interés en la temática cumpliendo con los criterios de inclusión. Resultados. Los artículos seleccionados abordan temática de rehabilitación Pulmonar en EPOC, con aplicación de protocolos que incluyen cuestionarios de evaluación respiratoria. Dentro de los resultados analizados, no se evidencia diferencia demográfica significativa entre los grupos intervenidos, la incidencia de participación es de 100 pacientes para cada programa de rehabilitación pulmonar, la media de edad es de 59 años, y los programas de rehabilitación se desarrollan a nivel hospitalario, comunitario y ambulatorio. Conclusiones. Implementar programas de rehabilitación pulmonar en pacientes con EPOC, constituye un elemento fundamental en el manejo de esta enfermedad, mostrando efectos benéficos al optimizar sintomatología, capacidad en el ejercicio, control sobre la enfermedad y mejoría en la calidad de vida.Introdução: A Doença Pulmonar Obstrutiva Crônica (DPOC) caracteriza-se por ser uma patologia evitável e tratável, que apresenta sintomas respiratórios permanentes devido à restrição progressiva do fluxo de ar. A reabilitação pulmonar tem mostrado melhora na atividade física, diminuição da dispneia e dos sintomas respiratórios, além de melhorar a qualidade de vida. O objetivo deste artigo é analisar as evidências científicas disponíveis sobre reabilitação pulmonar na doença pulmonar obstrutiva. Ma-teriais e métodos. Para a busca bibliográfica, foram incluídos artigos das bases de dados PudMed, Jane, Science Direct, Ovid, Medline, Proquest, publicados nos últimos cinco anos com evidências atualizadas em relação à reabilitação pulmonar de DPOC. Foram selecionados 53 artigos de interesse no assunto, atendendo aos critérios de inclusão. Resultados: Os artigos selecionados abordam a te-mática da reabilitação pulmonar na DPOC, com a aplicação de protocolos que incluem questionários de avaliação respiratória. Dentre os resultados analisados, não há diferença demográfica significativa entre os grupos intervencionados, a incidencia de participação é de 100 pacientes para cada programa de reabilitação pulmonar, a média de idade é de 59 anos, e os programas de reabilitação são desenvol-vidos em nível hospitalar, comunitário e ambulatorial. Conclusões: A implementação de programas de reabilitação pulmonar em pacientes com DPOC constitui elemento fundamental no manejo desta doença, apresentando efeitos benéficos pela otimização dos sintomas, capacidade de exercício, controle da doença e melhora da qualidade de vid

Transcranial modulation of brain oscillatory responses: A concurrent tDCS–MEG investigation

The physiological mechanisms underlying the effects of transcranial direct current stimulation (tDCS) are still largely unknown. To provide novel insight into the neurobiology of tDCS, stimulation was applied concurrently with Magnetoencephalography (MEG). This occurred while participants completed a visuomotor task before, during and after stimulation. Motor beta band (15–30 Hz) and visual gamma band (30–80 Hz) responses were localised using Synthetic Aperture Magnetometry (SAM). The resulting evoked and induced brain oscillatory responses were analysed. A significant reduction of average power was observed in the visual gamma band for anodal compared to sham stimulation. The magnitude of motor evoked responses was also demonstrated to be modulated by anodal tDCS. These results highlight that MEG can be used to draw inferences on the cortical mechanisms of DC stimulation

The speed of parietal theta frequency drives visuospatial working memory capacity

The speed of theta brain oscillatory activity is thought to play a key role in determining working memory (WM) capacity. Individual differences in the length of a theta cycle (ranging between 4 and 7 Hz) might determine how many gamma cycles (>30 Hz) can be nested into a theta wave. Gamma cycles are thought to represent single memory items; therefore, this interplay could determine individual memory capacity. We directly tested this hypothesis by means of parietal transcranial alternating current stimulation (tACS) set at slower (4 Hz) and faster (7 Hz) theta frequencies during a visuospatial WM paradigm. Accordingly, we found that 4-Hz tACS enhanced WM capacity, while 7-Hz tACS reduced WM capacity. Notably, these effects were found only for items presented to the hemifield contralateral to the stimulation site. This provides causal evidence for a frequency-dependent and spatially specific organization of WM storage, supporting the theta–gamma phase coupling theory of WM capacity

Experiencia del grupo de cirugía bariátrica y metabólica del Hospital Universitario de Neiva durante un año

Objective. Describe the surgical and metabolic results and changes to body image in patients undergoing bariatric surgery, in order to establish the effectiveness of the procedure in obese patients. Method and materials. Case study. The study examined the medical history of 35 patients who underwent bariatric surgery between September 2011 and September 2012. Results. 91% of patients had one or more associated comorbidities, of which gastrointestinal disorders were the most common. The most common technique was the gastric bypass. 12% developed postoperative complications. All patients reduced their bodyweight with an average body mass index (BMI) loss of 5.4 and 11.6 kg/m2 in the first and the sixth month respectively. Patients with a small intestine of 150cm lost more weight by the sixth month (2kg/m2 more) than those with a small intestine of 100cm. 98% reported a decrease in gastrointestinal symptoms and glycaemic levels reduced in 30%. 20% of diabetic patients and 12.5% of hypertensive patients continued taking medication for their conditions. Conclusions. Bariatric surgery is an effective technique to reduce BMI and improve comorbidities associated with obesity, thereby reducing the necessity of the use of medication. Self-perception of post-surgical body image improves considerably.Objetivo. Describir los resultados quirúrgicos, metabólicos y de percepción corporal obtenidos en pacientes sometidos a Cirugía Bariátrica, para establecer la efectividad del procedimiento en pacientes obesos. Materiales y métodos. estudio serie de casos. Se revisaron 35 historias clínicas de pacientes intervenidos quirúrgicamente por el equipo de Cirugía Bariátrica entre Septiembre del 2011 a septiembre del 2012. Resultados. El 91% de los pacientes presentó una o más comorbilidades asociadas, siendo las gastrointestinales las más frecuentes. La técnica más aplicada fue el Bypass gástrico. El 12% presentó complicaciones posquirúrgicas. Todos redujeron su peso con una media de pérdida de índice de masa corporal (IMC) al primer y sexto mes de 5.4 y 11,6 kg/m2 respectivamente. Los pacientes con asa alimentaria a 150cm tuvieron una mayor pérdida peso al sexto mes (2kg/m2 más) respecto a aquellos con asa alimentaria de 100cm. El 98% reportó disminución de los síntomas gastrointestinales y el 30% redujo las cifras de glicemia. El 20% de pacientes diabéticos y el 12,5% de los hipertensos continuaron con medicamentos para su enfermedad. Conclusiones. La Cirugía Bariátrica es una técnica efectiva para reducir el IMC y mejorar las comorbilidades asociadas a la obesidad. Así mismo, disminuye la necesidad del uso de medicamentos. La autopercepción de la imagen corporal posquirúrgica mejora ostensiblemente

Mortalidad perioperatoria en Tolima, perspectivas del cuarto indicador de The Lancet Commission on Global Surgery: un análisis preliminar de la cohorte prospectiva del estudio Colombian Surgical Outcomes Study (ColSOS)

Introducción. La mortalidad perioperatoria en el mundo representa 4,2 millones de muertes anuales. El cuarto indicador de The Lancet Commission on Global Surgery permite estandarizar la mortalidad perioperatoria. En Colombia, existen aproximaciones por datos secundarios, limitando el análisis y las intervenciones aplicables a nuestra población. El objetivo de este estudio fue describir la mortalidad perioperatoria a través de datos primarios que permitan sustentar políticas públicas. Métodos. Se hizo el análisis preliminar de un estudio observacional, de cohorte prospectiva, multicéntrico en 6 instituciones del departamento de Tolima. Se incluyeron los pacientes llevados a procedimientos quirúrgicos por una semana, con posterior seguimiento hasta el egreso, fallecimiento o 30 días de hospitalización. La mortalidad perioperatoria fue el desenlace primario. Resultados. Fueron incluidos 378 pacientes, con mediana de 49 años (RIC 32-66), buen estado funcional (ASA I-II 80 %) y baja complejidad quirúrgica (42 %). Las cirugías más comunes fueron por Ortopedia (25,4 %) y Cirugía plástica (23,3 %). El 29,7 % presentaron complicaciones postoperatorias, las más comunes fueron síndrome de dificultad respiratoria agudo e íleo postoperatorio. La mortalidad perioperatoria fue de 1,3 %. Discusión. La mortalidad perioperatoria discrepó de la reportada en otros estudios nacionales, aun cuando los pacientes tenían un bajo perfil de riesgo y baja complejidad de los procedimientos. Sin embargo, coincide con la reportada internacionalmente y nos acerca a la realidad del país. Conclusión. La determinación del cuarto indicador es de vital importancia para mejorar la atención quirúrgica en Colombia. Este es el primer acercamiento con datos primarios que nos permite tener información aplicable a nuestra población

Reorganizing the Intrinsic Functional Architecture of the Human Primary Motor Cortex during Rest with Non-Invasive Cortical Stimulation

The primary motor cortex (M1) is the main effector structure implicated in the generation of voluntary movements and is directly involved in motor learning. The intrinsic horizontal neuronal connections of M1 exhibit short-term and long-term plasticity, which is a strong substrate for learning-related map reorganization. Transcranial direct current stimulation (tDCS) applied for few minutes over M1 has been shown to induce relatively long-lasting plastic alterations and to modulate motor performance. Here we test the hypothesis that the relatively long-lasting synaptic modification induced by tDCS over M1 results in the alteration of associations among populations of M1 neurons which may be reflected in changes of its functional architecture. fMRI resting-state datasets were acquired immediately before and after 10 minutes of tDCS during rest, with the anode/cathode placed over the left M1. For each functional dataset, grey-matter voxels belonging to Brodmann area 4 (BA4) were labelled and afterwards BA4 voxel-based synchronization matrices were calculated and thresholded to construct undirected graphs. Nodal network parameters which characterize the architecture of functional networks (connectivity degree, clustering coefficient and characteristic path-length) were computed, transformed to volume maps and compared before and after stimulation. At the dorsolateral-BA4 region cathodal tDCS boosted local connectedness, while anodal-tDCS enhanced long distance functional communication within M1. Additionally, the more efficient the functional architecture of M1 was at baseline, the more efficient the tDCS-induced functional modulations were. In summary, we show here that it is possible to non-invasively reorganize the intrinsic functional architecture of M1, and to image such alterations

Neural correlates of evidence accumulation during value-based decisions revealed via simultaneous EEG-fMRI

Current computational accounts posit that, in simple binary choices, humans accumulate evidence in favour of the different alternatives before committing to a decision. Neural correlates of this accumulating activity have been found during perceptual decisions in parietal and prefrontal cortex; however the source of such activity in value-based choices remains unknown. Here we use simultaneous EEG–fMRI and computational modelling to identify EEG signals reflecting an accumulation process and demonstrate that the within- and across-trial variability in these signals explains fMRI responses in posterior-medial frontal cortex. Consistent with its role in integrating the evidence prior to reaching a decision, this region also exhibits task-dependent coupling with the ventromedial prefrontal cortex and the striatum, brain areas known to encode the subjective value of the decision alternatives. These results further endorse the proposition of an evidence accumulation process during value-based decisions in humans and implicate the posterior-medial frontal cortex in this process

Down-Regulation of Negative Emotional Processing by Transcranial Direct Current Stimulation: Effects of Personality Characteristics

Evidence from neuroimaging and electrophysiological studies indicates that the left dorsolateral prefrontal cortex (DLPFC) is a core region in emotional processing, particularly during down-regulation of negative emotional conditions. However, emotional regulation is a process subject to major inter-individual differences, some of which may be explained by personality traits. In the present study we used transcranial direct current stimulation (tDCS) over the left DLPFC to investigate whether transiently increasing the activity of this region resulted in changes in the ratings of positive, neutral and negative emotional pictures. Results revealed that anodal, but not cathodal, tDCS reduced the perceived degree of emotional valence for negative stimuli, possibly due to an enhancement of cognitive control of emotional expression. We also aimed to determine whether personality traits (extraversion and neuroticism) might condition the impact of tDCS. We found that individuals with higher scores on the introversion personality dimension were more permeable than extraverts to the modulatory effects of the stimulation. The present study underlines the role of the left DLPFC in emotional regulation, and stresses the importance of considering individual personality characteristics as a relevant variable, although replication is needed given the limited sample size of our study