Detecting Eating Episodes with an Ear-mounted Sensor

In this paper, we propose Auracle, a wearable earpiece that can automatically recognize eating behavior. More specifically, in free-living conditions, we can recognize when and for how long a person is eating. Using an off-the-shelf contact microphone placed behind the ear, Auracle captures the sound of a person chewing as it passes through the bone and tissue of the head. This audio data is then processed by a custom analog/digital circuit board. To ensure reliable (yet comfortable) contact between microphone and skin, all hardware components are incorporated into a 3D-printed behind-the-head framework. We collected field data with 14 participants for 32 hours in free-living conditions and additional eating data with 10 participants for 2 hours in a laboratory setting. We achieved accuracy exceeding 92.8% and F1 score exceeding 77.5% for eating detection. Moreover, Auracle successfully detected 20-24 eating episodes (depending on the metrics) out of 26 in free-living conditions. We demonstrate that our custom device could sense, process, and classify audio data in real time. Additionally, we estimateAuracle can last 28.1 hours with a 110 mAh battery while communicating its observations of eating behavior to a smartphone over Bluetooth

Early diagnosis of frailty: Technological and non-intrusive devices for clinical detection

This work analyses different concepts for frailty diagnosis based on affordable standard technology such as smartphones or wearable devices. The goal is to provide ideas that go beyond classical diagnostic tools such as magnetic resonance imaging or tomography, thus changing the paradigm; enabling the detection of frailty without expensive facilities, in an ecological way for both patients and medical staff and even with continuous monitoring. Fried's five-point phenotype model of frailty along with a model based on trials and several classical physical tests were used for device classification. This work provides a starting point for future researchers who will have to try to bridge the gap separating elderly people from technology and medical tests in order to provide feasible, accurate and affordable tools for frailty monitoring for a wide range of users.This work was sponsored by the Spanish Ministry of Science, Innovation and Universities and the European Regional Development Fund (ERDF) across projects RTC-2017-6321-1 AEI/FEDER, UE, TEC2016-76021-C2-2-R AEI/FEDER, UE and PID2019-107270RB-C21/AEI/10.13039/501100011033, UE

DETECTION OF HEALTH-RELATED BEHAVIOURS USING HEAD-MOUNTED DEVICES

The detection of health-related behaviors is the basis of many mobile-sensing applications for healthcare and can trigger other inquiries or interventions. Wearable sensors have been widely used for mobile sensing due to their ever-decreasing cost, ease of deployment, and ability to provide continuous monitoring. In this dissertation, we develop a generalizable approach to sensing eating-related behavior. First, we developed Auracle, a wearable earpiece that can automatically detect eating episodes. Using an off-the-shelf contact microphone placed behind the ear, Auracle captures the sound of a person chewing as it passes through the head. This audio data is then processed by a custom circuit board. We collected data with 14 participants for 32 hours in free-living conditions and achieved accuracy exceeding 92.8% and F1 score exceeding77.5% for eating detection with 1-minute resolution. Second, we adapted Auracle for measuring children’s eating behavior, and improved the accuracy and robustness of the eating-activity detection algorithms. We used this improved prototype in a laboratory study with a sample of 10 children for 60 total sessions and collected 22.3 hours of data in both meal and snack scenarios. Overall, we achieved 95.5% accuracy and 95.7% F1 score for eating detection with 1-minute resolution. Third, we developed a computer-vision approach for eating detection in free-living scenarios. Using a miniature head-mounted camera, we collected data with 10 participants for about 55 hours. The camera was fixed under the brim of a cap, pointing to the mouth of the wearer and continuously recording video (but not audio) throughout their normal daily activity. We evaluated performance for eating detection using four different Convolutional Neural Network (CNN) models. The best model achieved 90.9% accuracy and 78.7%F1 score for eating detection with 1-minute resolution. Finally, we validated the feasibility of deploying the 3D CNN model in wearable or mobile platforms when considering computation, memory, and power constraints

안경에서 기계적으로 증폭된 힘 측정을 통한 측두근 활동의 감지

학위논문 (박사)-- 서울대학교 대학원 공과대학 기계항공공학부, 2017. 8. 이건우.Recently, the form of a pair of glasses is broadly utilized as a wearable device that provides the virtual and augmented reality in addition to its natural functionality as a visual aid. These approaches, however, have lacked the use of its inherent kinematic structure, which is composed of both the temple and the hinge. When we equip the glasses, the force is concentrated at the hinge, which connects the head piece and the temple, from the law of the lever. In addition, since the temple passes through a temporalis muscle, chewing and wink activity, anatomically activated by the contraction and relaxation of the temporalis muscle, can be detected from the mechanically amplified force measurement at the hinge. This study presents a new and effective method for automatic and objective measurement of the temporalis muscle activity through the natural-born lever mechanism of the glasses. From the implementation of the load cell-integrated wireless circuit module inserted into the both hinges of a 3D printed glasses frame, we developed the system that responds to the temporalis muscle activity persistently regardless of various form factor different from each person. This offers the potential to improve previous studies by avoiding the morphological, behavioral, and environmental constraints of using skin-attached, proximity, and sound sensors. In this study, we collected data featured as sedentary rest, chewing, walking, chewing while walking, talking and wink from 10-subject user study. The collected data were transferred to a series of 84-dimentional feature vectors, each of which was composed of the statistical features of both temporal and spectral domain. These feature vectors, then, were used to define a classifier model implemented by the support vector machine (SVM) algorithm. The model classified the featured activities (chewing, wink, and physical activity) as the average F1 score of 93.7%. This study provides a novel approach on the monitoring of ingestive behavior (MIB) in a non-intrusive and un-obtrusive manner. It supplies the possibility to apply the MIB into daily life by distinguishing the food intake from the other physical activities such as walking, talking, and wink with higher accuracy and wearability. Furthermore, through applying this approach to a sensor-integrated hair band, it can be potentially used for the medical monitoring of the sleep bruxism or temporomandibular dysfunction.Abstract Chapter 1. Introduction 1.1. Motivation 1.1.1. Law of the Lever 1.1.2. Lever Mechanism in Human Body 1.1.3. Mechanical Advantage in Auditory Ossicle 1.1.4. Mechanical Advantage in Glasses 1.2. Background 1.2.1. Biological Information from Temporalis Muscle 1.2.2. Detection of Temporalis Muscle Activity 1.2.3. Monitoring of Ingestive Behavior 1.3. Research Scope and Objectives Chapter 2. Proof-of-Concept Validation 2.1. Experimental Apparatus 2.2. Measurement Results 2.3. Discussion Chapter 3. Implementation of GlasSense 3.1. Hardware Prototyping 3.1.1. Preparation 3.1.2. Load Cell-Integrated Circuit Module 3.1.3. 3D Printed Frame of Glasses 3.1.4. Hardware Integration 3.2. Data Acquisition System 3.2.1. Wireless Data Transmission 3.2.2. Data Collecting Module Chapter 4. Data Collection through User Study 4.1. Preparation for Experiment 4.2. Activity Recording Chapter 5. Feature Extraction 5.1. Signal Preprocessing and Segmentation 5.1.1. Temporal Frame 5.1.2. Spectral Frame 5.2. Feature Extraction 5.2.1. Temporal Features 5.2.2. Spectral Features 5.2.3. Feature Vector Generation Chapter 6. Classification of Featured Activity 6.1. Support Vector Machine (SVM) 6.2. Design of Classifier Model 6.2.1. Grid-Search 6.2.2. Cross-Validation 6.3. Classification Result 6.4. Performance Improvement 6.5. Discussion Chapter 7. Conclusions Bibliography 초록Docto

Detection of Swallowing Events to Quantify Fluid Intake in Older Adults Based on Wearable Sensors

The percentage of adults aged 65 an over, defined as older adults, is prospected to increase in the coming decades over the total population. With such an increase, it is essential that healthcare technologies evolve to cater for the needs of an aging population. One such need is hydration: due to both physiological and psychological reasons, older adults tend to be more prone to develop dehydration, which in turn increases the chances of morbidity and mortality. Currently, there are no gold standards to monitor hydration, with most methods relying on filling manual forms. Thus, there is an urgent need to develop techniques which can accurately monitor fluid intake and prevent dehydration in older adult, especially those residing in healthcare settings. Several methods, such as smart cups and on-body sensors such as microphones, were proposed in the literature, however none of these have been widely investigated, and often the presented results were based on an extremely small cohort. Therefore, the scope of this PhD project is to investigate and develop methods that can detect swallowing events and that can quantify the volume of ingested fluids by leveraging on signals harvested using non-invasive, on-body sensors. Two types of on-body sensors were selected and used throughout this research: namely surface Electromyographic sensors (sEMG) and microphones. These sensors were then used to collect sound and electric signals from the subjects while swallowing boluses of different viscosities and while performing actions not related to swallowing but that could recruit the same muscles or produce similar sounds, such as talking or coughing. Features were then extracted from the collected observations and used to train Machine Learning (ML) and Deep Learning (DL) models to analyse their ability to differentiate between swallowing and non-swallowing actions, to distinguish between different bolus types, and to quantify the volume of fluid ingested. Results showed a precision of 81.55±3.40% in differentiating between swallows and non-swallows and a precision of 81.74±8.01% in distinguishing between bolus types, both given by the sEMG. Also, a root mean square error (RMSE) of 3.94±1.31 ml in estimating fluid intake was obtained using the microphone. The significance of the findings exposed in this thesis rely on the fact that surface EMGs and microphones demonstrate a significant potential in fluid intake monitoring, and on the concrete possibility of developing a non-invasive, reliable system that could prevent dehydration in older adults living in healthcare settings

Diseño de un lazo de realimentación DSL para la eliminación del offset del electrodo en un amplificador capacitivo de instrumentación chopper que opera con voltaje de alimentación de 1V para electrocardiogramas

El presente trabajo de investigación desarrolla el diseño de un lazo de realimentación Servo DC (DSL), el cual buscará ser acoplado a un amplificador capacitivo de instrumentación Chopper para su uso en dispositivos wearables; por ello se limita el voltaje de alimentación a un valor de 1V. La señal principal a analizar será la de electrocardiografía (ECG), obtenida por medio de electrodos presentes en el dispositivo; sin embargo, debido a estos receptores se introduce una señal no deseada denominada como: el offset DC del electrodo (EDO). El DSL fue desarrollado como un circuito integrado, el cual funciona como integrador, filtrando la señal que se desea atenuar, de tal forma que esta realimentación interactúe con la señal de ECG, reduciendo el EDO que presenta antes de entrar a la etapa de amplificación. Por ello, se realiza el diseño del bloque integrador en una topología “fully differential” compuesto por 3 componentes principales: el transconductor (GM), el Amplificador Operacional (GM_DSL) y los capacitores del integrador (CINT). Este será desarrollado en la tecnología TSMC 180 nm; con el uso del software “Virtuoso Squematic Suite” y “Analog Design Enviroment XL” de Cadence. Las simulaciones utilizadas para este trabajo fueron: la transitoria, DC, AC y corner PVT. Dentro de los resultados obtenidos se obtuvo un GM de 390.21 pS, un GM_DSL con ganancia DC 88.8 dB y se seleccionaron capacitores CINT de 125 pF; estableciendo de esta forma una primera frecuencia de corte del circuito general alrededor de 0.5 Hz. Dicho valor es el adecuado, puesto que a magnitudes mayores que esta, comienza la señal de biopotencial ECG

Smart Sensors for Healthcare and Medical Applications

This book focuses on new sensing technologies, measurement techniques, and their applications in medicine and healthcare. Specifically, the book briefly describes the potential of smart sensors in the aforementioned applications, collecting 24 articles selected and published in the Special Issue “Smart Sensors for Healthcare and Medical Applications”. We proposed this topic, being aware of the pivotal role that smart sensors can play in the improvement of healthcare services in both acute and chronic conditions as well as in prevention for a healthy life and active aging. The articles selected in this book cover a variety of topics related to the design, validation, and application of smart sensors to healthcare