Advanced Signal Processing in Wearable Sensors for Health Monitoring

Smart, wearables devices on a miniature scale are becoming increasingly widely available, typically in the form of smart watches and other connected devices. Consequently, devices to assist in measurements such as electroencephalography (EEG), electrocardiogram (ECG), electromyography (EMG), blood pressure (BP), photoplethysmography (PPG), heart rhythm, respiration rate, apnoea, and motion detection are becoming more available, and play a significant role in healthcare monitoring. The industry is placing great emphasis on making these devices and technologies available on smart devices such as phones and watches. Such measurements are clinically and scientifically useful for real-time monitoring, long-term care, and diagnosis and therapeutic techniques. However, a pertaining issue is that recorded data are usually noisy, contain many artefacts, and are affected by external factors such as movements and physical conditions. In order to obtain accurate and meaningful indicators, the signal has to be processed and conditioned such that the measurements are accurate and free from noise and disturbances. In this context, many researchers have utilized recent technological advances in wearable sensors and signal processing to develop smart and accurate wearable devices for clinical applications. The processing and analysis of physiological signals is a key issue for these smart wearable devices. Consequently, ongoing work in this field of study includes research on filtration, quality checking, signal transformation and decomposition, feature extraction and, most recently, machine learning-based methods

Wearable System for Biosignal Acquisition and Monitoring Based on Reconfigurable Technologies

Wearable monitoring devices are now a usual commodity in the market, especially for the monitoring of sports and physical activity. However, specialized wearable devices remain an open field for high-risk professionals, such as military personnel, fire and rescue, law enforcement, etc. In this work, a prototype wearable instrument, based on reconfigurable technologies and capable of monitoring electrocardiogram, oxygen saturation, and motion, is presented. This reconfigurable device allows a wide range of applications in conjunction with mobile devices. As a proof-of-concept, the reconfigurable instrument was been integrated into ad hoc glasses, in order to illustrate the non-invasive monitoring of the user. The performance of the presented prototype was validated against a commercial pulse oximeter, while several alternatives for QRS-complex detection were tested. For this type of scenario, clustering-based classification was found to be a very robust option.This work was funded by Banco Santander and Centro Mixto UGR-MADOC through project SIMMA (code 2/16). The contribution of Víctor Toral was funded by the University of Granada through a grant from the “Iniciación a la investigación 2016” program. The contribution of Antonio García was partially funded by Spain’s Ministerio de Educación, Cultura y Deporte (Programa Estatal de Promoción del Talento y su Empleabilidad en I+D+i, Subprograma Estatal de Movilidad, within Plan Estatal de Investigación Científica y Técnica y de Innovación 2013-2016) under a “Salvador de Madariaga” grant (PRX17/00287). The contribution of Francisco J. Romero was funded by Spain’s Ministerio de Educación, Cultura y Deporte under a FPU grant (FPU16/01451). The contribution of Francisco M. Gómez-Campos was funded by Spain’s Ministerio de Economía, Industria y Competitividad under Project ENE2016_80944_R

Fall Prediction and Prevention Systems: Recent Trends, Challenges, and Future Research Directions.

Fall prediction is a multifaceted problem that involves complex interactions between physiological, behavioral, and environmental factors. Existing fall detection and prediction systems mainly focus on physiological factors such as gait, vision, and cognition, and do not address the multifactorial nature of falls. In addition, these systems lack efficient user interfaces and feedback for preventing future falls. Recent advances in internet of things (IoT) and mobile technologies offer ample opportunities for integrating contextual information about patient behavior and environment along with physiological health data for predicting falls. This article reviews the state-of-the-art in fall detection and prediction systems. It also describes the challenges, limitations, and future directions in the design and implementation of effective fall prediction and prevention systems

Understanding security risks and users perception towards adopting wearable Internet of Medical Things

This thesis examines users’ perception of trust within the context of security and privacy of Wearable Internet of Medical Things (WIoMT). WIoMT is a collective term for all medical devices connected to internet to facilitate collection and sharing of health-related data such as blood pressure, heart rate, oxygen level and more. Common wearable devices include smart watches and fitness bands. WIoMT, a phenomenon due to Internet of Things (IoT) has become prevalent in managing the day-to-day activities and health of individuals. This increased growth and adoption poses severe security and privacy concerns. Similar to IoT, there is a need to analyse WIoMT security risks as they are used by individuals and organisations on regular basis, risking personal and confidential information. Additionally, for better implementation, performance, adoption, and secured wearable medical devices, it is crucial to observe users’ perception. Users’ perspectives towards trust are critical for adopting WIoMT. This research aimed to understand users’ perception of trust in the adoption of WIoMT, while also exploring the security risks associated with adopting wearable IoMT. Employing a quantitative method approach, 189 participants from Western Sydney University completed an online survey. The results of the study and research model indicated more than half of the variance (R2 = 0.553) in the Intention to Use WIoMT devices, which was determined by the significant predictors (95% Confidence Interval; p < 0.05), Perceived Usefulness, Perceived Ease of Use and Perceived Security and Privacy. Among these two, the domain Perceived Security and Privacy was found to have significant outcomes. Hence, this study reinforced that a WIoMT user intends to use the device only if he/she trusts the device; trust here has been defined in terms of its usefulness, easy to use and security and privacy features. This finding will be a steppingstone for equipment vendors and manufacturers to have a good grasp on the health industry, since the proper utilisation of WIoMT devices results in the effective and efficient management of health and wellbeing of users. The expected outcome from this research also aims to identify how users’ security and perception matters while adopting WIoMT, which in future can benefit security professionals to examine trust factors when implementing new and advanced WIoMT devices. Moreover, the expected result will help consumers as well as different healthcare industry to create a device which can be easily adopted and used securely by consumers

Screen use objectively assessed from images captured by a wearable camera and its association with BMI and energy intake

PURPOSE: Television (TV) viewing remains a popular form of screen time for adults. However, it is important to understand the obesity risks associated with other screens, not only TV, in a changing media landscape. This study aimed to examine the association between energy intake, BMI, and screen time using the data obtained from the AIM-2 wearable camera. METHODS: The AIM-2 device was used by (n=18) participants for seven consecutive days. Three days of images from the device were analyzed for energy intake, and 1 of these days was coded for screen use (i.e., TV, phone, and computer), the number of screens, and screen duration while eating. A preliminary analysis of screen use in relation to BMI and energy intake was conducted. Potential confounders (age, sex, race, ethnicity, marital status, and education level) were considered. RESULTS: Phones were the most used screen type, and TV alone was not watched by any participants. While eating, screens were used 73% of the time. Participants with the highest screen time usage consumed more total energy than those with the lowest screen time usage (p<0,.05). This difference was attenuated when controlling for duration of eating, perhaps suggesting that higher screen time usage may lead to an extended eating duration and, thus, higher intakes of energy. There were no statistically significant associations between any screen time variable (type, duration, or number of screens used) and BMI. Screen time usage was examined during four time periods: before 11:00 am; 11:00 am-2:59 pm; 3:00 pm-7:59 pm; 8:00 pm, and later. There was a statistically significant positive association between higher screen time after 8:00 pm and total daily energy intake (P=0.005). CONCLUSION: Eating while using a screen can be objectively assessed using the AIM-2 device. Our data agree with recent studies showing that phones and computers are used more than TV. While there were no significant associations between any of these screen variables and BMI, data from a single day in this study suggests that those with the highest screen time usage tended to have higher energy intakes. In addition, there was also a statistically significant association between screen time usage while eating later in the evening (after 8:00 pm) and total daily energy intake. These preliminary results should be interpreted with caution due to the small sample size and the availability of only one day of screen use and energy intake. Future studies should examine more than one day and use wearable cameras for objective evaluations of screen use

Psychophysiological analysis of a pedagogical agent and robotic peer for individuals with autism spectrum disorders.

Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by ongoing problems in social interaction and communication, and engagement in repetitive behaviors. According to Centers for Disease Control and Prevention, an estimated 1 in 68 children in the United States has ASD. Mounting evidence shows that many of these individuals display an interest in social interaction with computers and robots and, in general, feel comfortable spending time in such environments. It is known that the subtlety and unpredictability of people’s social behavior are intimidating and confusing for many individuals with ASD. Computerized learning environments and robots, however, prepare a predictable, dependable, and less complicated environment, where the interaction complexity can be adjusted so as to account for these individuals’ needs. The first phase of this dissertation presents an artificial-intelligence-based tutoring system which uses an interactive computer character as a pedagogical agent (PA) that simulates a human tutor teaching sight word reading to individuals with ASD. This phase examines the efficacy of an instructional package comprised of an autonomous pedagogical agent, automatic speech recognition, and an evidence-based instructional procedure referred to as constant time delay (CTD). A concurrent multiple-baseline across-participants design is used to evaluate the efficacy of intervention. Additionally, post-treatment probes are conducted to assess maintenance and generalization. The results suggest that all three participants acquired and maintained new sight words and demonstrated generalized responding. The second phase of this dissertation describes the augmentation of the tutoring system developed in the first phase with an autonomous humanoid robot which serves the instructional role of a peer for the student. In this tutoring paradigm, the robot adopts a peer metaphor, where its function is to act as a peer. With the introduction of the robotic peer (RP), the traditional dyadic interaction in tutoring systems is augmented to a novel triadic interaction in order to enhance the social richness of the tutoring system, and to facilitate learning through peer observation. This phase evaluates the feasibility and effects of using PA-delivered sight word instruction, based on a CTD procedure, within a small-group arrangement including a student with ASD and the robotic peer. A multiple-probe design across word sets, replicated across three participants, is used to evaluate the efficacy of intervention. The findings illustrate that all three participants acquired, maintained, and generalized all the words targeted for instruction. Furthermore, they learned a high percentage (94.44% on average) of the non-target words exclusively instructed to the RP. The data show that not only did the participants learn nontargeted words by observing the instruction to the RP but they also acquired their target words more efficiently and with less errors by the addition of an observational component to the direct instruction. The third and fourth phases of this dissertation focus on physiology-based modeling of the participants’ affective experiences during naturalistic interaction with the developed tutoring system. While computers and robots have begun to co-exist with humans and cooperatively share various tasks; they are still deficient in interpreting and responding to humans as emotional beings. Wearable biosensors that can be used for computerized emotion recognition offer great potential for addressing this issue. The third phase presents a Bluetooth-enabled eyewear – EmotiGO – for unobtrusive acquisition of a set of physiological signals, i.e., skin conductivity, photoplethysmography, and skin temperature, which can be used as autonomic readouts of emotions. EmotiGO is unobtrusive and sufficiently lightweight to be worn comfortably without interfering with the users’ usual activities. This phase presents the architecture of the device and results from testing that verify its effectiveness against an FDA-approved system for physiological measurement. The fourth and final phase attempts to model the students’ engagement levels using their physiological signals collected with EmotiGO during naturalistic interaction with the tutoring system developed in the second phase. Several physiological indices are extracted from each of the signals. The students’ engagement levels during the interaction with the tutoring system are rated by two trained coders using the video recordings of the instructional sessions. Supervised pattern recognition algorithms are subsequently used to map the physiological indices to the engagement scores. The results indicate that the trained models are successful at classifying participants’ engagement levels with the mean classification accuracy of 86.50%. These models are an important step toward an intelligent tutoring system that can dynamically adapt its pedagogical strategies to the affective needs of learners with ASD

Enabling human physiological sensing by leveraging intelligent head-worn wearable systems

This thesis explores the challenges of enabling human physiological sensing by leveraging head-worn wearable computer systems. In particular, we want to answer a fundamental question, i.e., could we leverage head-worn wearables to enable accurate and socially-acceptable solutions to improve human healthcare and prevent life-threatening conditions in our daily lives? To that end, we will study the techniques that utilise the unique advantages of wearable computers to (1) facilitate new sensing capabilities to capture various biosignals from the brain, the eyes, facial muscles, sweat glands, and blood vessels, (2) address motion artefacts and environmental noise in real-time with signal processing algorithms and hardware design techniques, and (3) enable long-term, high-fidelity biosignal monitoring with efficient on-chip intelligence and pattern-driven compressive sensing algorithms. We first demonstrate the ability to capture the activities of the user's brain, eyes, facial muscles, and sweat glands by proposing WAKE, a novel behind-the-ear biosignal sensing wearable. By studying the human anatomy in the ear area, we propose a wearable design to capture brain waves (EEG), eye movements (EOG), facial muscle contractions (EMG), and sweat gland activities (EDA) with a minimal number of sensors. Furthermore, we introduce a Three-fold Cascaded Amplifying (3CA) technique and signal processing algorithms to tame the motion artefacts and environmental noises for capturing high-fidelity signals in real time. We devise a machine-learning model based on the captured signals to detect microsleep with a high temporal resolution. Second, we will discuss our work on developing an efficient Pattern-dRiven Compressive Sensing framework (PROS) to enable long-term biosignal monitoring on low-power wearables. The system introduces tiny on-chip pattern recognition primitives (TinyPR) and a novel pattern-driven compressive sensing technique (PDCS) that exploits the sparsity of biosignals. They provide the ability to capture high-fidelity biosignals with an ultra-low power footprint. This development will unlock long-term healthcare applications on wearable computers, such as epileptic seizure monitoring, microsleep detection, etc. These applications were previously impractical on energy and resource-constrained wearable computers due to the limited battery lifetime, slow response rate, and inadequate biosignal quality. Finally, we will further explore the possibility of capturing the activities of a blood vessel (i.e., superficial temporal artery) lying deep inside the user's ear using an ear-worn wearable computer. The captured optical pulse signals (PPG) are used to develop a frequent and comfortable blood pressure monitoring system called eBP. In contrast to existing devices, eBP introduces a novel in-ear wearable system design and algorithms to eliminate the need to block the blood flow inside the ear, alleviating the user's discomfort