A smart detection method for sleep posture based on a flexible sleep monitoring belt and vital sign signals.

People spend approximately one-third of their lives in sleep, but more and more people are suffering from sleep disorders. Sleep posture is closely related to sleep quality, so related detection is very significant. In our previous work, a smart flexible sleep monitoring belt with MEMS triaxial accelerometer and pressure sensor has been developed to detect the vital signs, snore events and sleep stages. However, the method for sleep posture detection has not been studied. Therefore, to achieve high performance, low cost and comfortable experience, this paper proposes a smart detection method for sleep posture based on a flexible sleep monitoring belt and vital sign signals measured by a MEMS Inertial Measurement Unit (IMU). Statistical analysis and wavelet packet transform are applied for the feature extraction of the vital sign signals. Then the algorithm of recursive feature elimination with cross-validation is introduced to further extract the key features. Besides, machine learning models with 10-fold cross validation process, such as decision tree, random forest, support vector machine, extreme gradient boosting and adaptive boosting, were adopted to recognize the sleep posture. 15 subjects were recruited to participate the experiment. Experimental results demonstrate that the detection accuracy of the random forest algorithm is the highest among the five machine learning models, which reaches 96.02 %. Therefore, the proposed sleep posture detection method based on the flexible sleep monitoring belt is feasible and effective.

Monitoring of Cardiorespiratory Parameters during Sleep Using a Special Holder for the Accelerometer Sensor.

Sleep is extremely important for physical and mental health. Although polysomnography is an established approach in sleep analysis, it is quite intrusive and expensive. Consequently, developing a non-invasive and non-intrusive home sleep monitoring system with minimal influence on patients, that can reliably and accurately measure cardiorespiratory parameters, is of great interest. The aim of this study is to validate a non-invasive and unobtrusive cardiorespiratory parameter monitoring system based on an accelerometer sensor. This system includes a special holder to install the system under the bed mattress. The additional aim is to determine the optimum relative system position (in relation to the subject) at which the most accurate and precise values of measured parameters could be achieved. The data were collected from 23 subjects (13 males and 10 females). The obtained ballistocardiogram signal was sequentially processed using a sixth-order Butterworth bandpass filter and a moving average filter. As a result, an average error (compared to reference values) of 2.24 beats per minute for heart rate and 1.52 breaths per minute for respiratory rate was achieved, regardless of the subject's sleep position. For males and females, the errors were 2.28 bpm and 2.19 bpm for heart rate and 1.41 rpm and 1.30 rpm for respiratory rate. We determined that placing the sensor and system at chest level is the preferred configuration for cardiorespiratory measurement. Further studies of the system's performance in larger groups of subjects are required, despite the promising results of the current tests in healthy subjects.

Hearables, in-ear sensing devices for bio-signal acquisition: a narrative review.

INTRODUCTION: Hearables are ear devices used for multiple purposes including ubiquitous/remote monitoring of vital signals. This can support early detection, prevention, and management of urgent/non-urgent healthcare needs. This review therefore seeks to analyze the challenges and capabilities of hearables used to monitor human physiological signals. AREAS COVERED: Studies were identified via search (Medline, Embase, Web of Science, Cochrane Library, Scopus) and conducted in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses. Bias assessment used the Mixed Methods Appraisal Tool 2018 and Quality Assessment of Diagnostic Accuracy Studies 2nd Edition. 92/631 studies met the inclusion criteria and were qualitatively analyzed. The outcomes, applications, advantages, and limitations were discussed according to the vital signal measured. The bias risk ranged from low to high, with most studies facing moderate-to-high risk in subject selection due to small sample sizes. EXPERT OPINION: Most studies reported good outcomes for ear signal acquisition compared to reference devices. To improve practicability and implementation, wireless connectivity, battery life, impact of motion/environmental artifacts and comfort need to be addressed going forward. Hearable technologies have also shown potential synergies with hearing aids. In future, multimodal ear-sensing devices opens the possibility of comprehensive health monitoring within daily life.

Review-Microwave Radar Sensing Systems for Search and Rescue Purposes.

This paper presents a survey of recent developments using Doppler radar sensor in searching and locating an alive person under debris or behind a wall. Locating a human and detecting the vital signs such as breathing rate and heartbeat using a microwave sensor is a non-invasive technique. Recently, many hardware structures, signal processing approaches, and integrated systems have been introduced by researchers in this field. The purpose is to enhance the accuracy of vital signs' detection and location detection and reduce energy consumption. This work concentrates on the representative research on sensing systems that can find alive people under rubble when an earthquake or other disasters occur. In this paper, various operating principles and system architectures for finding survivors using the microwave radar sensors are reviewed. A comparison between these systems is also discussed.

Probabilities of False Alarm for Vital Sign Detection on the Basis of a Doppler Radar System.

Vital detection on the basis of Doppler radars has drawn a great deal of attention from researchers because of its high potential for applications in biomedicine, surveillance, and finding people alive under debris during natural hazards. In this research, the signal-to-noise ratio (SNR) of the remote vital-sign detection system is investigated. On the basis of different types of noise, such as phase noise, Gaussian noise, leakage noise between the transmitting and receiving antennae, and so on, the SNR of the system has first been examined. Then the research has focused on the investigation of the detection and false alarm probabilities of the system when the transmission link between the human and the radar sensor system took the Nakagami-m channel model. The analytical model for the false alarm and the detection probabilities of the system have been derived. The proposed theoretical models for the SNR and detection probability match with the simulation and measurement results. These theoretical models have the potential to be used as good references for the hardware development of the vital-sign detection radar sensor system.

Cognitive bio-radar: The natural evolution of bio-signals measurement.

In this article we discuss a novel approach to Bio-Radar, contactless measurement of bio-signals, called Cognitive Bio-Radar. This new approach implements the Bio-Radar in a Software Defined Radio (SDR) platform in order to obtain awareness of the environment where it operates. Due to this, the Cognitive Bio-Radar can adapt to its surroundings in order to have an intelligent usage of the radio frequency spectrum to improve its performance. In order to study the feasibility of such implementation, a SDR based Bio-Radar testbench was developed and evaluated. The prototype is shown to be able to acquire the heartbeat activity and the respiratory effort. The acquired data is compared with the acquisitions from a Biopac research data acquisition system, showing coherent results for both heartbeat and breathing rate.

Effect of change in patient's bed angles on pain after coronary angiography according to vital signals.

BACKGROUND: One of the most common and important diagnostic methods for the detection of heart diseases is coronary angiography. The aim of this study was to determine the optimum angle of the bed by using vital signals to optimize the patient's position after the angiography. MATERIALS AND METHODS: This study was a randomized clinical trial (RCT) on participants after angiography who were divided into five groups. The first group was placed routinely in a supine position. In the other groups, all of the patients were placed in bed by angle 15°, 30°, 45°, and 60° upward. In each group, vital signals were measured that included blood pressure, percent of blood oxygen saturation, heart rate, respiratory rate, and temperature. All of measured data compared with the pain score has been achieved from numerical pain scale. The data were analyzed by descriptive statistics method, variance analysis, and post hoc tests in the Statistical Package for the Social Sciences (SPSS) software, version 16. Estimation of the relationship was done by MATLAB version 2011. The level of significance was considered to be 0.05. RESULTS: In various groups, there was no significance difference in demographic variables such as gender, age, height, and weight. The mean of pain score, heart rate, systolic blood pressure, and respiratory rate changed significantly (P < 0.05) but the temperature variation, blood oxygen saturation, and diastolic blood pressure in subjects were not significant (P > 0.05). It showed linear changes between pain and systolic blood pressure, respiratory rate, and heart rate changes. A dramatic reduction was also seen in systolic blood pressure, respiratory rate, heart rate, and also pain at an angle of 45(°). CONCLUSION: This study showed that, 45(°) was the best angle of the bed to optimize the patient's position after the procedure, based on his/her vital signs and pain score. Thus, in order to relive pain, this change in bed angle is advised to be planned by postangiography nurses in patients after coronary angiography.

An oximetry-based method for monitoring reactions of autistic subjects under music auditions / Metodologia baseada em oximetria para monitoramento das reações de sujeitos autistas em audções musicais

This work aims to create a methodology to analyse the physiological effects of people exposed to sounds, specifically music and its elements, using techniques of data acquisition and signal processing to provide objective information on the subjects’reactions, in order to help the use of music in music therapy for autistics. We used a pulse oximeter with data transmission capability, data acquisition and signal processing software. The subjects and/or groups were exposed to several types of music, varying its elements, and the physiologic measurement signals were made. The acquired information data base was then converted into graphics representative of heart rate and arterial hemoglobin saturation. During the measurements, the subjects’ behaviour has been observed to relate subjective and objective results. Two groups of subjects (six non autistics and six autistics with diagnosis established) participated on this research, with ages ranging from 7 to 24 years old. As the majority of autistics are male, only boys have been invited to participate of this study. An observation protocol based on autistics behaviour was developed, the vital signals and the subjects reactions were observed and recorded. The results allow to identify and establish in an objective way any influence of music in human behaviour through sound stimulation and vital signals monitoring: SpO2 and HR.

O objetivo deste trabalho foi criar uma metodologia que possibilite analisar os efeitos fisiológicos produzidos pela exposição de pessoas à música e seus elementos, utilizando princípios de detecção, aquisição de dados e processamento de sinais, obtendo-se informações objetivas sobre as reações dos sujeitos, para dar subsídios ao emprego da música na musicoterapia com autistas. Foram utilizados um oxímetro de pulso com capacidade de transmissão de dados e aplicativos para aquisição de dados e processamento dos sinais. Foram realizados experimentos com a exposição dos sujeitos a vários tipos de músicas, com a variação de seus elementos, criando-se, assim, um banco de dados com as medições realizadas, a seguir transformando essa informação em gráficos representativos da evolução dos sinais de FC e de SpO2. Durante as medições, o comportamento dos sujeitos foi observado para que o resultado da análise subjetiva fosse relacionado com as medições objetivas. Os sujeitos desta pesquisa encontram-se na faixa etária entre 7 e 24 anos, sendo que a amostra estabelecida foi composta por seis indivíduos não autistas e seis indivíduos com diagnóstico de autismo estabelecido. Como o maior percentual de autistas é do sexo masculino, apenas de sujeitos do sexo masculino participaram. Foi desenvolvido um protocolo de observação baseado no comportamento de autistas, e os sinais vitais foram adquiridos e processados. Como resultado, foi identificada de forma objetiva a influência da música no comportamento humano pelo monitoramento dos estímulos sonoros e dos sinais vitais de SpO2 e FC.