Seamless Healthcare Monitoring: Advancements in Wearable, Attachable, and Invisible Devices
Abstract
This book shares the knowledge of active and prestigious worldwide researchers and scholars in the field of healthcare monitoring as authors investigate historical developments, summarize latest advancements, and envision future prospects on wearable, attachable, and invisible devices that monitor diverse physiological information. The coverage of the book spans multiple disciplines, from biomechanics, to bioelectricity, biochemistry, biophysics and biomaterials. There is also wide coverage of various physical and chemical quantities such as electricity, pressure, flow, motion, force, temperature, gases, and biomarkers. Each chapter explores the background of a specific monitoring device, as well as its physical and chemical principles and instrumentation, signal processing and data analysis, achieved outcomes and application scenarios, and future research topics. There are chapters on:
• Electrocardiograms, electroencephalograms, and electromyograms
• Measurement of flow phenomenon
• Latest wearable technologies for the quantification of human motion
• Various forms of wearable thermometers
• Monitoring of gases and chemical substances produced during metabolism…and more!
This book is appropriate and accessible for students and scientists, as well as researchers in biomedical engineering, computer engineers, healthcare entrepreneurs, administrative officers, policy makers, market vendors, and healthcare personnel. It helps to provide us with insights into future endeavors, formulate innovative businesses and services, and will help improve people’s health and quality of life.
... The interaction of light with biological tissue can be quite complex and may involve scattering, absorption and/or reflection. 51 For example, it was previously shown that darker skin pigmentation may attenuate the permeability of light wavelengths shorter than 650 nm. 37 The importance of skin tone is underlined by our systematic literature review, showing that skin tone or at least ethnicity was considered as a confounder in 20 studies. ...
... It was previously shown that the waveform of the PPG signal may be affected by the contact force between the sensor and the measurement site and that the waveform of the obtained PPG signal differs depending on the PPG probe contact. 51 The authors further stated that the most accurate PPG signal may be obtained under conditions of transmural pressure, defined as the pressure difference between the inside and outside of blood vessels (ie, the pressure across the wall of the blood vessel). Interestingly, none of the studies identified by our systematic search reported that contact pressure was measured. ...
Assessing vital signs such as heart rate (HR) by
wearable devices in a lifestyle-related environment
provides widespread opportunities for public health
related research and applications. Commonly,
consumer wearable devices assessing HR are based on
photoplethysmography (PPG), where HR is determined by
absorption and reflection of emitted light by the blood.
However, methodological differences and shortcomings
in the validation process hamper the comparability of
the validity of various wearable devices assessing HR.
Towards Intelligent Health and Well-Being: Network
of Physical Activity Assessment (INTERLIVE) is a joint
European initiative of six universities and one industrial
partner. The consortium was founded in 2019 and strives
towards developing best-practice recommendations
for evaluating the validity of consumer wearables and
smartphones. This expert statement presents a bestpractice validation protocol for consumer wearables
assessing HR by PPG. The recommendations were
developed through the following multi-stage process:
(1) a systematic literature review based on the Preferred
Reporting Items for Systematic Reviews and MetaAnalyses, (2) an unstructured review of the wider
literature pertaining to factors that may introduce bias
during the validation of these devices and (3) evidenceinformed expert opinions of the INTERLIVE Network. A
total of 44 articles were deemed eligible and retrieved
through our systematic literature review. Based on these
studies, a wider literature review and our evidenceinformed expert opinions, we propose a validation
framework with standardised recommendations using
six domains: considerations for the target population,
criterion measure, index measure, testing conditions, data
processing and the statistical analysis. As such, this paper
presents recommendations to standardise the validity
testing and reporting of PPG-based HR wearables used
by consumers. Moreover, checklists are provided to guide
the validation protocol development and reporting. This
will ensure that manufacturers, consumers, healthcare
providers and researchers use wearables safely and to its
full potential.
... Here, we can see that the pressure range from 5 to 15 kPa is the most suitable for S p O 2 monitoring. This pressure range is close to the largest PPG amplitude obtained pressure range (8 to 12 kPa) for a reflectance sensor attached to the forehead region above the eye [30][31][32]. Thus, in future studies, it is suggested to apply the designed sensor to measure the forehead S p O 2 value. ...
... Here, we can see that the pressure range from 5 to 15 kPa is the most suitable for SpO2 monitoring. This pressure range is close to the largest PPG amplitude obtained pressure range (8 to 12 kPa) for a reflectance sensor attached to the forehead region above the eye [30][31][32]. Thus, in future studies, it is suggested to apply the designed sensor to measure the forehead SpO2 value. ...
A novel optical sensor probe combining monitoring of blood oxygen saturation (SpO2) with contact pressure is presented. This is beneficial as contact pressure is known to affect SpO2 measurement. The sensor consists of three plastic optical fibres (POF) used to deliver and collect light for pulse oximetry, and a fibre Bragg grating (FBG) sensor to measure contact pressure. All optical fibres are housed in a biocompatible epoxy patch which serves two purposes: (i) to reduce motion artefacts in the photoplethysmogram (PPG), and (ii) to transduce transverse loading into an axial strain in the FBG. Test results show that using a combination of pressure measuring FBG with a reference FBG, reliable results are possible with low hysteresis which are relatively immune to the effects of temperature. The sensor is used to measure the SpO2 of ten volunteers under different contact pressures with perfusion and skewness indices applied to assess the quality of the PPG. The study revealed that the contact force ranging from 5 to 15 kPa provides errors of <2%. The combined probe has the potential to improve the reliability of reflectance oximeters. In particular, in wearable technology, the probe should find use in optimising the fitting of garments incorporating this technology.
... A 3-axis accelerometer can detect linear acceleration along each axis, whereas gyroscopes can detect angular velocity. For details on this sensing technology, we refer to the book by Tamura and Chen [14]. Fig. 3 illustrates the general block diagram of direct sensing technology for motion detection. ...
Abnormal body motion in infants may be associated with neurodevelopmental delay or critical illness. In contrast to continuous patient monitoring of the basic vitals, the body motion of infants is only determined by discrete periodic clinical observations of caregivers, leaving the infants unattended for observation for a longer time. One step to fill this gap is to introduce and compare different sensing technologies that are suitable for continuous infant body motion quantification. Therefore, we conducted this systematic review for infant body motion quantification based on the PRISMA method (Preferred Reporting Items for Systematic Reviews and Meta-Analyses). In this systematic review, we introduce and compare several sensing technologies with motion quantification in different clinical applications. We discuss the pros and cons of each sensing technology for motion quantification. Additionally, we highlight the clinical value and prospects of infant motion monitoring. Finally, we provide suggestions with specific needs in clinical practice, which can be referred by clinical users for their implementation. Our findings suggest that motion quantification can improve the performance of vital sign monitoring, and can provide clinical value to the diagnosis of complications in infants.
... The majority of previous studies carried out on the determination of HR on wrist-worn devices have shown limited accuracy [85,[106][107][108], typically with measurements that may be somewhat understated [76,[109][110][111]. A number of studies have attempted to correlate wearable HR measurements by PPG with those from a reference ECG signal as a gold standard [20,51,85,93,109]. Indeed, Boudreaux et al. simultaneously determined the accuracy of eight wearable devices, six wrist-worn, one chest-worn, and one ear-worn, during a graded cycling exercise test and during a structured resistance exercise regimen [111]. ...
Citation: Martín-Escudero, P.; Cabanas, A.M.; Dotor-Castilla, M.L.; Galindo-Canales, M.; Miguel-Tobal, F.; Fernández-Pérez, C.; Fuentes-Ferrer, M.; Giannetti, R. Are Abstract: The market for wrist-worn devices is growing at previously unheard-of speeds. A consequence of their fast commercialization is a lack of adequate studies testing their accuracy on varied populations and pursuits. To provide an understanding of wearable sensors for sports medicine, the present study examined heart rate (HR) measurements of four popular wrist-worn devices, the (Fitbit Charge (FB), Apple Watch (AW), Tomtom runner Cardio (TT), and Samsung G2 (G2)), and compared them with gold standard measurements derived by continuous electrocardiogram examination (ECG). Eight athletes participated in a comparative study undergoing maximal stress testing on a cycle ergometer or a treadmill. We analyzed 1,286 simultaneous HR data pairs between the tested devices and the ECG. The four devices were reasonably accurate at the lowest activity level. However, at higher levels of exercise intensity the FB and G2 tended to underestimate HR values during intense physical effort, while the TT and AW devices were fairly reliable. Our results suggest that HR estimations should be considered cautiously at specific intensities. Indeed, an effective intervention is required to register accurate HR readings at high-intensity levels (above 150 bpm). It is important to consider that even though none of these devices are certified or sold as medical or safety devices, researchers must nonetheless evaluate wrist-worn wearable technology in order to fully understand how HR affects psychological and physical health, especially under conditions of more intense exercise.
... The focus of this section is mainly to summarize the types of EEG electrodes and associated front-end amplifiers utilised in current wearable integrated EEG-fNIRS systems. To note, there are relevant systematic reviews on EEG background [51,52], wearable EEG [9], electrode type [53,54], electrode materials [55], and EEG signal processing [56]. This section does not aim to replicate these reviews. ...
There has been considerable interest in applying electroencephalography (EEG) and functional near-infrared spectroscopy (fNIRS) simultaneously for multimodal assessment of brain function. EEG–fNIRS can provide a comprehensive picture of brain electrical and hemodynamic function and has been applied across various fields of brain science. The development of wearable, mechanically and electrically integrated EEG–fNIRS technology is a critical next step in the evolution of this field. A suitable system design could significantly increase the data/image quality, the wearability, patient/subject comfort, and capability for long-term monitoring. Here, we present a concise, yet comprehensive, review of the progress that has been made toward achieving a wearable, integrated EEG–fNIRS system. Significant marks of progress include the development of both discrete component-based and microchip-based EEG–fNIRS technologies; modular systems; miniaturized, lightweight form factors; wireless capabilities; and shared analogue-to-digital converter (ADC) architecture between fNIRS and EEG data acquisitions. In describing the attributes, advantages, and disadvantages of current technologies, this review aims to provide a roadmap toward the next generation of wearable, integrated EEG–fNIRS systems.
... To assess the performance of the DPSS, verification of the measurement was performed by the Pedar® system insoles (Novel GmbH, Munich), which is considered the golden standard for feet plantar pressure measurement for gait analysis (Tamura & Chen, 2018). Each Pedar insole contains 99 pressure sensors, and the measurement is sampled at 50Hz or 100Hz, and transmitted to the computer via Bluetooth connection. ...
Conformal contact with skin is a critical requirement for wearable electronics in medical healthcare, artificial electronics, and human–computer interfaces. Tattoo‐like electronics exploiting water‐dissolvable polymers have been introduced to directly transfer electronics to the skin increasing conformality and adhesion. However, water‐dissolvable polymers cannot be anchored on the skin while maintaining electrical properties because water‐based sweat can destroy the polymer substrate. In this study, we present a transparent and skin‐attachable electrode (TSE) composed of highly conductive silver nanowires and biocompatible polyurethane composite using surface redissolution by ethanol. The TSE can be fabricated into various patterns by a simple fabrication method and firmly mounted on the skin. There was no reddishness or residue on the attached spot after detachment. Additionally, the TSE showed low mechanical modulus of 225 kPa and an optical transmittance of ≈70% at 550 nm. Stable and conformal contact with the skin leads to effective body motion sensing and sensitive electrophysiological signal acquisition due to the low electrical interfacial impedance. Highly conductive silver nanowires and biocompatible polyurethane composite can be exploited as transparent and skin‐attachable electrode (TSE) using surface redissolution by ethanol. The TSE has no side effect on the skin such as reddishness or polymer residue. Stable and conformal contact with the skin leads to effective body motion sensing and sensitive electrophysiological signal acquisition due to the low electrical interfacial impedance.
IoT has become an essential resource in health applications, mainly for the monitoring of chronic diseases with integration with wearable devices, which helps to analyze symptoms in a non-invasive way, becoming a highly qualified resource for the health care of the patient. Novel Covid-19 disease emerged from China in December 2019 and became a problem of global concern the following year. Elderly and people with comorbidities are the most affected, causing a critical health condition or even death. Therefore, remote monitoring is necessary in patients with Covid-19 to avoid health complications caused by irregular conditions such as silent hypoxia. This paper proposes an efficient, low-cost, and rapidly assembled wearable IoT device model, focused on monitoring the health of the Covid-19 patients, including oxygen saturation and body temperature measurements with the aim of notifying patients and medical experts of health status during disease. Implementation is based on Espressif’s ESP32 SoC (System on a Chip) using its connectivity resources for Wi-Fi communication toward IoT platform in order to deploy physiological measurements in mobile devices and alert in case of critical values. The results of the prototype implementation are compared to commercial medical devices to demonstrate the functionality and efficiency of the wearable IoT device model.
The emerging approach of personalised healthcare is known to be facilitated by the Internet of Things (IoT) and sensor-based IoT devices are in popular demand for healthcare providers due to the constant need for patient monitoring. In epilepsy, the most common and complex patients to deal with correspond to those with multiple strands of epilepsy, it is these patients that require long term monitoring assistance. These extremely varied kind of patients should be monitored precisely according to their key symptoms, hence specific characteristics of each patient should be identified, and medical treatment tailored accordingly. Consequently, paradigms are needed to personalise the information being defined by the condition of these patients each with their very individual signs and symptoms of epilepsy. Therefore, by focusing upon personalised parameters that make epilepsy patients distinct from each other this paper proposes an IoT based Epilepsy monitoring model that endorses a more accurate and refined way of remotely monitoring and managing the ‘individual’ patient.
Information technology has been applied to health management. In our laboratory, we have developed and produced prototypes of new sensors, and attempted to monitor various health parameters noninvasively and unobtrusively. This paper reviews the results of our research related to sensor development. The contents include unobtrusive monitoring in the bed, bath and toilet, and smart house. Then wearable sensors used for photoplethysmography, inertia sensor, deep body temperature measurement, and oxygen uptake monitor are presented. Finally, the requirement of regulatory science is commented
For infants admitted at neonatal intensive care unit, the continuous monitoring of health parameters is critical for their optimal treatment and outcomes. So it’s crucial to provide proper treatment, accurate and comfortable monitoring conditions for newborn infants. In this paper, we propose wearable sensor systems integrated with flexible material based non-invasive sensors for neonatal monitoring. The system aims at providing reliable vital signs monitoring as well as comfortable clinical en vironments for neonatal care. The system consists of a smart vest and a cloud platform. In the smart vest, a novel stretching sensor based on Polydimethylsiloxane-Graphene (PDMS-Graphene) compound is created to detect newborns’ respiration signal; textile-based dry electrodes are developed to measure Electrocardiograph (ECG) signals; inertial measurement units (IMUs) are embedded to obtain movement information including accelerated speed and angular velocity of newborn wrists. Experiments were conducted to systematically test the sensing related characteristics of the aforementioned flexible materials and the performance of the proposed multi-sensor platform. The results show that the proposed system can achieve high quality signals. The wearable sensor platform is promising for continuous long term monitoring of neonates. The multimodal physiological and behavioral signals measured by the platform can be further processed for clinical decision support on the neonatal health status.
Medical data belongs to whom it produces it. In an increasing manner, this data is usually processed in unauthorized third-party clouds that should never have the opportunity to access it. Moreover, recent data protection regulations (e.g., GDPR) pave the way towards the development of privacy-preserving processing techniques. In this paper, we present a proof of concept of a streaming IoT architecture that securely processes cardiac data in the cloud combining trusted hardware and Spark. The additional security guarantees come with no changes to the application's code in the server. We tested the system with a database containing ECGs from wearable devices comprised of 8 healthy males performing a standardized range of in-lab physical activities (e.g., run, walk, bike). We show that, when compared with standard Spark Streaming, the addition of privacy comes at the cost of doubling the execution time.
Wearable sensors placed behind-the-ear are emerging as being very promising for unobtrusive long term monitoring. Factors such as gait, electroencephalography (EEG), and ballistocardiography (BCG) can all be measured from behind-the-ear in a socially acceptable hearing aid based form factor. Previous works have investigated the recording of electrocardiography (ECG) from the ear, but generally with one electrode placed some distance away from the ear itself. This paper uses recently introduced tattoo electrodes to investigate whether ECG components can indeed be measured from behind a single ear. Compared to a reference photophelsmography (PPG) device we show that the fundamental heart beat frequency is present in behind-the-ear ECG only in half of the cases considered. In contrast the second harmonic is present in all records and could allow the extraction of heart rate to within a few beats-per-minute accuracy. Further signal processing work is required to allow the automated extraction of this, particularly when working with short time windows of data, but our results characterize the signal and demonstrate the principle of behind-the-ear ECG collected from a single ear.
Wearable thermometers are popular devices for measuring body temperature during fever, as well as basal temperature in women. They are easy to handle, inexpensive, and accurate and provide continuous recordings. Most wearable thermometers connect to a smartphone or tablet to display data. Many forms of wearable thermometer are available, such as touch, patch, and invisible (radiometry) types. In this review, we describe and discuss currently available wearable thermometers.
This chapter provides an introduction to the field of automatic dietary monitoring (ADM) that intends to derive diet-related behaviour information from unobtrusive sensors and data analysis algorithms. A conceptual gap found in most literature reviews on the relation of physiology and dietary activities is filled. A consistent knowledge-based physiological model for dietary activities is presented. A biomedical approach is adopted to retrieve phenomenological insights of the food preparation, intake, and digestion processes. A taxonomy of dietary activities and a literature review of wearable sensing approaches and dietary dimensions across all dietary activities are also presented.
The development of wearable chemical sensors is of interest to obtain comprehensive information for health promotion. However, the development of wearable sensors faces many challenges for long-term use, easy handling, response time, accuracy, validity, and reliability. There are several imitations to produce simple wearable sensors, and above these, optical gas sensors are a promising tool. Monitoring of oxygenation by pulse oximeter and components of expired gas by capnometer is a successful technology. In this section, these two sensors are reviewed including sensor principle and limitation of use.
Seamless monitoring of chemical substances plays a key role in long-term health management, forensics, and security applications. Numerous wearable sensors have been developed to detect different kinds of chemical substances, such as gas, ethanol, urine, glucose, DNA, RNA, and so on. Gas emitted by human can be selectively detected by gas sensor and used as a reference in clinical diagnosis. Glucose sensor can detect the exact concentration of glucose in human blood and can also be used for controllable insulin delivery to reduce the pain to diabetic. The trace elements sensor can detect extremely low concentrations of elements in bio-sample that can be acted as an indicator for certain disease. Moreover, biomarker sensor provides an elusive goal for molecular diagnostics with high accuracy, which is an important tool in early preclinical diagnosis. Portable sensors can be used to detect the amount of ethanol in exhaled gas to confirm whether a driver gets drunk driving. The chemical substances are basically divided into four categories: gas/odor, glucose, trace elements, and biomarker. These sensors could be operated by electrochemical reaction, optical detector, and/or immune antigen-antibody reaction. Electrochemical sensors operate by reacting with the substances of interest and producing an electrical signal proportional to the concentration of analyte (such as hydrogen peroxide in body fluids). The purpose of an optical sensor is to measure a physical quantity of light (such as the amount of light that is scattered by analyte), depending on the type of sensor, and convert the readout to an integrated device to display. Immunosensors can be operated by immunochemical reaction in which antibody immobilized on the solid-state devices can couple with desired analyte (antigens) to produce a transducer signal that can be detected by electrochemical or optical device. Based on the high selectivity of antigen-antibody reaction, the immunosensors can be used for accurate and fast detection of certain biomarker.
Ming Huang, and Tatsuo Togawa Part VI Gases and Chemical Substances
- Toshiyo Tamura
Toshiyo Tamura, Ming Huang, and Tatsuo Togawa
Part VI Gases and Chemical Substances
Josep Sol a, Ilkka Korhonen, and Mattia Bertschi Index
- . . . . Physical Activity
- Philippe Delgado-Gonzalo
- Alia Renevey
- Mathieu Lemkaddem
- Lemay
Physical Activity....................................... 413
Ricard Delgado-Gonzalo, Philippe Renevey, Alia Lemkaddem,
Mathieu Lemay, Josep Sol a, Ilkka Korhonen, and Mattia Bertschi
Index................................................... 457