A unified methodology for heartbeats detection in seismocardiogram and ballistocardiogram signals

This work presents a methodology to analyze and segment both seismocardiogram (SCG) and ballistocardiogram (BCG) signals in a unified fashion. An unsupervised approach is followed to extract a template of SCG/BCG heartbeats, which is then used to fine-tune temporal waveform annotation. Rigorous performance assessment is conducted in terms of sensitivity, precision, Root Mean Square Error (RMSE) and Mean Absolute Error (MAE) of annotation. The methodology is tested on four independent datasets, covering different measurement setups and time resolutions. A wide application range is therefore explored, which better characterizes the robustness and generality of the method with respect to a single dataset. Overall, sensitivity and precision scores are uniform across all datasets (p > 0.05 from the Kruskal–Wallis test): the average sensitivity among datasets is 98.7%, with 98.2% precision. On the other hand, a slight yet significant difference in RMSE and MAE scores was found (p < 0.01) in favor of datasets with higher sampling frequency. The best RMSE scores for SCG and BCG are 4.5 and 4.8 ms, respectively; similarly, the best MAE scores are 3.3 and 3.6 ms. The results were compared to relevant recent literature and are found to improve both detection performance and temporal annotation errors

Applying the EFuNN Evolving Paradigm to the Recognition of Artefactual Beats in Continuous Seismocardiogram Recordings

Seismocardiogram (SCG) recording is a novel method for the prolonged monitoring of the cardiac mechanical performance during spontaneous behavior. The continuous monitoring results in a collection of thousands of beats recorded during a variety of physical activities so that the automatic analysis and processing of such data is a challenging task due to the presence of artefactual beats and morphological changes over time that currently request the human expertise. On this premise, we propose the use of the Evolving Fuzzy Neural Network (EFuNN) paradigm for the automatic artifact detection in the SCG signal. The fuzzy logic processing method can be applied to model the human expertise knowledge using the learning capabilities of an artificial neural network. The evolving capability of the EFuNN paradigm has been applied to solve the issue of the physiological variability of the SGC waveform. Preliminary tests have been carried out to validate this approach and the obtained results demonstrate the effectiveness of the method and its scalability

Carbon Nanotube Wearable Sensors for Health Diagnostics.

This perspective article highlights a recent surge of interest in the application of textiles containing carbon nanotube (CNT) sensors for human health monitoring. Modern life puts more and more pressure on humans, which translates into an increased number of various health disorders. Unfortunately, this effect either decreases the quality of life or shortens it prematurely. A possible solution to this problem is to employ sensors to monitor various body functions and indicate an upcoming disease likelihood at its early stage. A broad spectrum of materials is currently under investigation for this purpose, some of which already entered the market. One of the most promising materials in this field are CNTs. They are flexible and of high electrical conductivity, which can be modulated upon several forms of stimulation. The article begins with an illustration of techniques for how wearable sensors can be built from them. Then, their application potential for tracking various health parameters is presented. Finally, the article ends with a summary of this field's progress and a vision of the key directions to domesticate this concept

Comparison of Different Methods for Estimating Cardiac Timings: A Comprehensive Multimodal Echocardiography Investigation

Cardiac time intervals are important hemodynamic indices and provide information about left ventricular performance. Phonocardiography (PCG), impedance cardiography (ICG), and recently, seismocardiography (SCG) have been unobtrusive methods of choice for detection of cardiac time intervals and have potentials to be integrated into wearable devices. The main purpose of this study was to investigate the accuracy and precision of beat-to-beat extraction of cardiac timings from the PCG, ICG and SCG recordings in comparison to multimodal echocardiography (Doppler, TDI, and M-mode) as the gold clinical standard. Recordings were obtained from 86 healthy adults and in total 2,120 cardiac cycles were analyzed. For estimation of the pre-ejection period (PEP), 43% of ICG annotations fell in the corresponding echocardiography ranges while this was 86% for SCG. For estimation of the total systolic time (TST), these numbers were 43, 80, and 90% for ICG, PCG, and SCG, respectively. In summary, SCG and PCG signals provided an acceptable accuracy and precision in estimating cardiac timings, as compared to ICG

Telemonitoring systems for respiratory patients: technological aspects.

Abstract This review introduces the reader to the available technologies in the field of telemonitoring, with focus on respiratory patients. In the materials and methods section, a general structure of telemonitoring systems for respiratory patients is presented and the sensors of interest are illustrated, i.e., respiratory monitors (wearable and non-wearable), activity trackers, pulse oximeters, environmental monitors and other sensors of physiological variables. Afterwards, the most common communication protocols are briefly introduced. In the results section, selected clinical studies that prove the significance of the presented parameters in chronic respiratory diseases are presented. This is followed by a discussion on the main current issues in telemedicine, in particular legal aspects, data privacy and benefits both in economic and health terms

New Electrochemical Sensors for Decentralized Analysis

Nous sensors electroquímics per a analisis decentralitzats és una tesis que emmarca diferents aspectes del desenvolupament de sensors potenciomètrics, des de la seva fabricació, el diseny adequat, i finalment, la seva aplicabilitat en escenaris reals. En el context actual, l'evolució de la tecnologia, especialment l'aparició a nivell global d'internet, i la disponibilitat d'aquesta a baix cost han permès la creació d'eines que ens permeten connectar el món físic i, en el cas d'aquesta tesis, el món químic a la xarxa. Aquesta connexió aporta un nou grau dins l'escala de valor per a la societat actual. Concretament, aquesta aportació tecnològica va adreçada a superar els nous reptes de l'actualitat, com poden ser la sostenibilitat del sistema sanitari a causa de l'embelliment de la societat, el control medioambiental, així com també mantenir la seguretat per a la societat del benestar del futur. Així doncs, aquesta tesis presenta solucions efectives per al desenvolupament d'eines de captació d'informació que serviràn per nudrir a la societat de major coneixement. Conseqüentment, produint nous negocis al voltant, de la fabricació, processament i creació de valor entorn a aquestes dades. La recerca i desenvolupament de sensors potenciomètrics integrats a la roba per detectar els nivells d'electròlits i sensors senzills de paper per a la determinació de biomolècules, com la glucosa, són alguns dels objectius aconseguits en aquesta tesis. A més a més, sensors integrats en globus permeten l'estudi de les seves propietats mecàniques i electroquímiques, així com també, aporten noves solucions a problemes reals. Totes aquestes aplicacions serveixen de portals de captació d'informació química cap a la integració dins la nova societat de la informació.Nuevos sensores electroquímicos para analisis decentralizados es una tesis que enmarca diferentes aspectos del desarrollo de sensores potenciométricos, desde su fabricación, el diseño adecuado, i finalmente, su aplicabilidad en escenarios reales. En el contexto actual, la evolución de la tecnología, especialmente la aparición a nivel global de internet, y la disponibilidad de esta a bajo coste han permitido la creación de herramientas que nos permiten conectar el mundo físico y, en el caso de esta tesis, el mundo químico a la red. Esta conexión aporta un nuevo grado dentro la escala de valor para la sociedad actual. Concretamente, esta aportación tecnológica va dirigida a superar los nuevos retos de la actualidad, como pueden ser la sostenibilidad del sistema sanitario a causa del envejecimiento de la poblacion, el control medioambiental, así como también mantener la seguridad para la sociedad del bienestar del futuro. Entonces, esta tesis presenta soluciones efectivas para el desarrollo de herramientas de captación de información que servirán para nutrir a la sociedad de un mayor conocimiento. Por consiguiente, produciendo nuevos negocios alrededor, de la fabricación, procesado i creación de valor en los datos obtenidos. La investigación y desarrollo de sensores potenciométricos integrados en la ropa para detectar los niveles de electrolitos y sensores simples en papel para la determinación de biomoléculas, como la glucosa, son algunos de los objetivos conseguidos en esta tesis. Además, sensores integrados en globos permiten el estudio de sus propiedades mecánicas y electroquímicas, así como, aportando nuevas soluciones a problemas reales. Todas estas aplicaciones sirven de portales de captación de información química hacia la integración dentro de la nueva sociedad de la información.ew Electrochemical Sensors for Decentralized Analysis is a thesis that wisely discuss the developments of potentiometric sensors, from the fabrication step, the use of a suitable design, to the applicability in real scenarios. Nowadays, the evolution of technology, specially the creation of the global internet network, and the low-cost availability of such technology have allowed the development of tools that connect the physical world and, addressed in this thesis, the chemical world into the network. This connection adds a new level in the value chain for the present society. Precisely, this technology approach is focus on circumvent new present challenges of society. For instance, sustainability of the healthcare system caused by the population aging, environmental monitoring, as well as, keep security and safety to the welfare of society of the future. Therefore, this thesis presents successful solutions for the development of tools to gather chemical information. This information will nurture society with high-value knowledge. Accordingly, new business development from, sensing products, data treatment and information management are going to be created. Research and development of potentiometric sensors integrated into garments for electrolyte detection and simple sensors built in paper for biomolecules determination, such as glucose, and liquid monitoring, such as sweat, are some of the accomplished objectives from this thesis. Furthermore, balloon-embedded sensors allow the study of the mechanical and electrochemical properties of the electrodes, as well as, contributing with new solutions to real problems. All the applications developed in this thesis are utilized as gateways for chemical information acquisition towards the integration into the new information society