Papers by Negman Alvarado
Diseño de control tipo Joystick para vehículos eléctricos como scooteer y sillas de ruedas motorizadas, 2021
Diseño de control tipo Joystick para vehículos eléctricos como scooteer y sillas de ruedas motori... more Diseño de control tipo Joystick para vehículos eléctricos como scooteer y sillas de ruedas motorizadas
Sistema biométrico para el análisis de la marcha utilizando unidades de medida inerciales (IMU) B... more Sistema biométrico para el análisis de la marcha utilizando unidades de medida inerciales (IMU) Biometrics system for gait analysis using inertial measurement units (IMU)
Romanian Journal of Neurology, Dec 31, 2021
Stroke is a leading cause of death and disability worldwide. The advent of acute reperfusion ther... more Stroke is a leading cause of death and disability worldwide. The advent of acute reperfusion therapy, intravenous thrombolysis and endovascular thrombectomy, has revolutionised the field of stroke medicine, and neurology in general. Recent studies have implicated a major role of cerebral collaterals in the trajectory of acute ischemic stroke patients receiving reperfusion therapy. Collaterals sustain blood supply to the tissue in the setting of acute ischaemia which prevents further expansion of the hypoperfused tissue, playing an important role in determining outcomes after acute ischaemic stroke. The use of collateral assessment in routine practice in acute ischaemic stroke, let alone in reperfusion therapy, is far from universal and limited. Future work in embedding collateral assessment in standards of care in acute stroke and management is warranted. This article provides a comprehensive update on the diagnostic and prognostic utility of collaterals in acute ischaemic stroke and recommendations on collateral-based decision making in acute stroke and steps that can be taken for its rapid uptake in clinical practice.
Journal of Computer Science and Technology, Apr 17, 2021
This paper introduces a practical technique for the design of an instrument used in air flow meas... more This paper introduces a practical technique for the design of an instrument used in air flow measurement or flowmeter. This instrument is an essential component in the hospital medical ventilation equipment functioning, therefore, the parameters design presented in this article focus on this purpose. However, this instrument can be employed to any measurement scale. The technique is based on indirect flow measurement, using a sensor that converts the flow parameter into a differential pressure measurement. An electronic transducer allows the differential pressure values to be obtained as an electrical signal, which is then digitized and analyzed to obtain the original parameter. The experimental procedure presented in this paper utilizes a computational algorithm to perform the signal analysis; however, given the simplicity of the procedure, this could be adapted to any digital processing card or platform, to show the measurement obtained immediately. Preliminary analyses demonstrated instrument efficiency with sensitivity of 0.0681 liters per second (L/s). Accuracy evaluation showed an average measurement error lesser than 1.4%, with a standard deviation of 0.0612 and normal distribution over the set of test measurements.
Journal of Diabetes, Dec 23, 2021
BackgroundDiabetes is a cardiometabolic comorbidity that may predispose COVID‐19 patients to wors... more BackgroundDiabetes is a cardiometabolic comorbidity that may predispose COVID‐19 patients to worse clinical outcomes. This study sought to determine the prevalence of diabetes in hospitalized COVID‐19 patients and investigate the association of diabetes severe COVID‐19, rate of acute respiratory distress syndrome (ARDS), mortality, and need for mechanical ventilation by performing a systematic review and meta‐analysis.MethodsIndividual studies were selected using a defined search strategy, including results up until July 2021 from PubMed, Embase, and Cochrane Central Register of Controlled Trials. A random‐effects meta‐analysis was performed to estimate the proportions and level of association of diabetes with clinical outcomes in hospitalized COVID‐19 patients. Forest plots were generated to retrieve the odds ratios (OR), and the quality and risk assessment was performed for all studies included in the meta‐analysis.ResultsThe total number of patients included in this study was 10 648, of whom 3112 had diabetes (29.23%). The overall pooled estimate of prevalence of diabetes in the meta‐analysis cohort was 31% (95% CI, 0.25‐0.38; z = 16.09, P < .0001). Diabetes significantly increased the odds of severe COVID‐19 (OR 3.39; 95% CI, 2.14‐5.37; P < .0001), ARDS (OR 2.55; 95% CI, 1.74‐3.75; P = <.0001), in‐hospital mortality (OR 2.44; 95% CI, 1.93‐3.09; P < .0001), and mechanical ventilation (OR 3.03; 95% CI, 2.17‐4.22; P < .0001).ConclusionsOur meta‐analysis demonstrates that diabetes is significantly associated with increased odds of severe COVID‐19, increased ARDS rate, mortality, and need for mechanical ventilation in hospitalized patients. We also estimated an overall pooled prevalence of diabetes of 31% in hospitalized COVID‐19 patients.
Romanian Journal of Neurology, Dec 31, 2021
Stroke is a leading cause of death and disability worldwide. The advent of acute reperfusion ther... more Stroke is a leading cause of death and disability worldwide. The advent of acute reperfusion therapy, intravenous thrombolysis and endovascular thrombectomy, has revolutionised the field of stroke medicine, and neurology in general. Recent studies have implicated a major role of cerebral collaterals in the trajectory of acute ischemic stroke patients receiving reperfusion therapy. Collaterals sustain blood supply to the tissue in the setting of acute ischaemia which prevents further expansion of the hypoperfused tissue, playing an important role in determining outcomes after acute ischaemic stroke. The use of collateral assessment in routine practice in acute ischaemic stroke, let alone in reperfusion therapy, is far from universal and limited. Future work in embedding collateral assessment in standards of care in acute stroke and management is warranted. This article provides a comprehensive update on the diagnostic and prognostic utility of collaterals in acute ischaemic stroke and recommendations on collateral-based decision making in acute stroke and steps that can be taken for its rapid uptake in clinical practice.
This article presents the hardware development stage of a high-resolution and low-noise multi-cha... more This article presents the hardware development stage of a high-resolution and low-noise multi-channel bioamplifier, designed to acquire 8 channels of biopotential signals by human brain emitted. Basically it's an 8-lead electroencephalograph (EEG), but designed to pick up signals with wide bandwidth, compared to common EEGs. This bioamplifier is made with the purpose of acquire signals from specific brain sectors, for frequency patterns study higher than the ranges commonly analyzed in conventional electroencephalography. The obtained product consists of 8 identical circuits coupled to capture all the signals with respect to a central electrode. Each circuits consists of a differential amplifier with common mode voltage feedback circuits, which allow improve the noise rejection ratio. High efficiency AC coupling circuits are used to reduce baseline shift without signal altering. Each lead has gain of 10000, to obtain amplitude levels in the Volts order from the signals captured ...
espanolEn este articulo se presenta una tecnica simple pero eficiente para el diseno de un instru... more espanolEn este articulo se presenta una tecnica simple pero eficiente para el diseno de un instrumento utilizado en la medicion de flujo de aire o caudalimetro. Este instrumento es de uso imprescindible en el funcionamiento de equipos de ventilacion medica hospitalaria, por consiguiente, los parametros de diseno presentados en este articulo se enfocan para este fin. Sin embargo, el desarrollo de este instrumento puede ser aplicado a cualquier escala de medicion. La tecnica se basa en la medicion indirecta del caudal, utilizando un sensor que convierte el parametro de flujo en una medicion de presion diferencial. Un transductor electronico permite obtener los valores de presion diferencial como una senal electrica, que luego se digitaliza y se analiza para obtener el parametro que originalmente se desea medir. El procedimiento experimental que se presenta utiliza un computador para realizar el analisis de la senal, pero el procedimiento es simple de adaptar a cualquier tarjeta digita...
This article presents the hardware development stage of a high-resolution and low-noise multi-cha... more This article presents the hardware development stage of a high-resolution and low-noise multi-channel bioamplifier, designed to acquire 8 channels of biopotential signals by human brain emitted. Basically it's an 8-lead electroencephalograph (EEG), but designed to pick up signals with wide bandwidth, compared to common EEGs. This bioamplifier is made with the purpose of acquire signals from specific brain sectors, for frequency patterns study higher than the ranges commonly analyzed in conventional electroencephalography. The obtained product consists of 8 identical circuits coupled to capture all the signals with respect to a central electrode. Each circuits consists of a differential amplifier with common mode voltage feedback circuits, which allow improve the noise rejection ratio. High efficiency AC coupling circuits are used to reduce baseline shift without signal altering. Each lead has gain of 10000, to obtain amplitude levels in the Volts order from the signals captured ...
Processing technique for detecting indices that indicate the MU wave presence in EEG signal, 2019
Modern studies have shown that mirrow neurons are involved in the development of social empathy a... more Modern studies have shown that mirrow neurons are involved in the development of social empathy and language. Consequently, deficiency in mirror neural networks response could be one of the dysfunctions present in autistic spectrum disorder (ASD), as a phenotypic functional expression of channelopathies in some brain regions. Early detection of deficiencies in mirror neural network systems could allow more efficient applications of behavioral therapies in patients with ASD. The detection of MU waves in the electroencephalogram (EEG) could be an interesting technique that refers to the functioning of these neural networks. In this article we present a simple technique, developed with the purpose of identifying the presence of MU waves in the EEG record. It consists of a processing that analyzes each one of the derivations of the EEG, with the implementation of a mathematical method. The signal analysis looks for the changes in the frequency patterns related to the MU waves, discriminating the presence of alpha waves by the association to the patient's response to a conditioned visual stimulus. The preliminary results prove the efficiency of the system. The analysis emphasized frequency alterations in the range of 9 to 12 Hz. The most important responses were obtained with the processing of leads C3, Cz and C4.
espanolEn este articulo se presenta una tecnica simple pero eficiente para el diseno de un instru... more espanolEn este articulo se presenta una tecnica simple pero eficiente para el diseno de un instrumento utilizado en la medicion de flujo de aire o caudalimetro. Este instrumento es de uso imprescindible en el funcionamiento de equipos de ventilacion medica hospitalaria, por consiguiente, los parametros de diseno presentados en este articulo se enfocan para este fin. Sin embargo, el desarrollo de este instrumento puede ser aplicado a cualquier escala de medicion. La tecnica se basa en la medicion indirecta del caudal, utilizando un sensor que convierte el parametro de flujo en una medicion de presion diferencial. Un transductor electronico permite obtener los valores de presion diferencial como una senal electrica, que luego se digitaliza y se analiza para obtener el parametro que originalmente se desea medir. El procedimiento experimental que se presenta utiliza un computador para realizar el analisis de la senal, pero el procedimiento es simple de adaptar a cualquier tarjeta digita...
Alzheimer's & Dementia, 2012
Revista Peruana de Investigación en Salud, Jul 10, 2019
Modern studies have shown that mirrow neurons are involved in the development of social empathy a... more Modern studies have shown that mirrow neurons are involved in the development of social empathy and language. Consequently, deficiency in mirror neural networks response could be one of the dysfunctions present in autistic spectrum disorder (ASD), as a phenotypic functional expression of channelopathies in some brain regions. Early detection of deficiencies in mirror neural network systems could allow more efficient applications of behavioral therapies in patients with ASD. The detection of MU waves in the electroencephalogram (EEG) could be an interesting technique that refers to the functioning of these neural networks. In this article we present a simple technique, developed with the purpose of identifying the presence of MU waves in the EEG record. It consists of a processing that analyzes each one of the derivations of the EEG, with the implementation of a mathematical method. The signal analysis looks for the changes in the frequency patterns related to the MU waves, discriminating the presence of alpha waves by the association to the patient's response to a conditioned visual stimulus. The preliminary results prove the efficiency of the system. The analysis emphasized frequency alterations in the range of 9 to 12 Hz. The most important responses were obtained with the processing of leads C3, Cz and C4.
Alzheimer's & Dementia, 2012
Frontiers in Cardiovascular Medicine
Revista Peruana de Investigación en Salud
Estudios modernos han demostrado que las neuronas espejo están involucradas en el desarrollo de l... more Estudios modernos han demostrado que las neuronas espejo están involucradas en el desarrollo de la empatía social y el lenguaje. En consecuencia, una deficiencia en la respuesta de las redes neuronales espejo podría ser una de las disfunciones presentes en el trastorno del espectro autista (TEA), como expresión funcional fenotípica de las canalopatías en algunas regiones cerebrales. La detección temprana de las deficiencias en los sistemas de redes neuronales espejo, podría permitir aplicaciones más eficientes de las terapias comportamentales en los pacientes con TEA. La detección de las ondas MU en el Electroencefalograma (EEG) podría ser una técnica interesante que hace referencia al funcionamiento de estas redes neuronales.En este artículo se presenta una técnica simple, desarrollada con el propósito de identificar la presencia de ondas MU en el registro EEG. Consiste en un procesamiento que analiza cada una de las derivaciones del EEG, con la implementación de un método matemáti...
Revista Peruana de Investigación en Salud
Estudios modernos han demostrado que las neuronas espejo están involucradas en el desarrollo de l... more Estudios modernos han demostrado que las neuronas espejo están involucradas en el desarrollo de la empatía social y el lenguaje. En consecuencia, una deficiencia en la respuesta de las redes neuronales espejo podría ser una de las disfunciones presentes en el trastorno del espectro autista (TEA), como expresión funcional fenotípica de las canalopatías en algunas regiones cerebrales. La detección temprana de las deficiencias en los sistemas de redes neuronales espejo, podría permitir aplicaciones más eficientes de las terapias comportamentales en los pacientes con TEA. La detección de las ondas MU en el Electroencefalograma (EEG) podría ser una técnica interesante que hace referencia al funcionamiento de estas redes neuronales.En este artículo se presenta una técnica simple, desarrollada con el propósito de identificar la presencia de ondas MU en el registro EEG. Consiste en un procesamiento que analiza cada una de las derivaciones del EEG, con la implementación de un método matemáti...
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Papers by Negman Alvarado