A novel sensor for wrist based optical heart rate monitor
01 May 2017-pp 1-6
TL;DR: A novel 590 nm (yellow-orange) wavelength based optical system is tailored suitably to maximize the signal quality acquired and holds an advantage over its shorter counterpart when subjected to varied skin pigmentation levels.
Abstract: The growing demands of continuous healthcare and hence physiological monitoring necessitates a system with high reliability and accuracy. Wearable used for continuous cardiological parameter estimation from wrist use reflective photoplethysmography technique that has certain limitations which are imperative. One such constraint is skin pigmentation of the subject. In the present work a sensor module design is proposed addressing to the anomalies due to optical properties of skin. A novel 590 nm (yellow-orange) wavelength based optical system is tailored suitably to maximize the signal quality acquired. The proposed setup is validated on a conglomeration of subjects in terms of age, gender and skin tone. A generous agreement between coherent measures for signal quality shows that the proposed wavelength holds an advantage over its shorter counterpart when subjected to varied skin pigmentation levels. A maximum improvement factor of 71 is observed in case of perfusion index, 31 for pulsatile strength and 3 for SNR. The details of sensor design, experimental setup, validation protocol, observations and inferences drawn from the study are presented.
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21 Feb 2007
704 citations
TL;DR: A taxonomy of sensors, functionalities, and methods used in non-invasive wrist-wearable devices was assembled and the main features of commercial wrist- wearable devices are presented.
Abstract: Wearable devices have recently received considerable interest due to their great promise for a plethora of applications. Increased research efforts are oriented towards a non-invasive monitoring of human health as well as activity parameters. A wide range of wearable sensors are being developed for real-time non-invasive monitoring. This paper provides a comprehensive review of sensors used in wrist-wearable devices, methods used for the visualization of parameters measured as well as methods used for intelligent analysis of data obtained from wrist-wearable devices. In line with this, the main features of commercial wrist-wearable devices are presented. As a result of this review, a taxonomy of sensors, functionalities, and methods used in non-invasive wrist-wearable devices was assembled.
180 citations
Cites background from "A novel sensor for wrist based opti..."
...[77] proposed a sensor module design addressing anomalies due to the optical properties of skin....
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TL;DR: In this article, a comprehensive review of the literature that aims to summarize these noise sources for future photoplethysmography (PPG) device development for use in health monitoring is presented.
77 citations
TL;DR: Wearable devices with embedded photoplethysmography (PPG) sensors enable continuous monitoring of cardiovascular activity, allowing for the detection cardiovascular problems, such as arrhythmias, unless methods can be identified to improve low quality signal segments.
Abstract: Objective Wearable devices with embedded photoplethysmography (PPG) sensors enable continuous monitoring of cardiovascular activity, allowing for the detection cardiovascular problems, such as arrhythmias. However, the quality of wrist-based PPG is highly variable, and is subject to artifacts from motion and other interferences. The goal of this paper is to evaluate the signal quality obtained from wrist-based PPG when used in an ambulatory setting. Approach Ambulatory data were collected over a 24 h period for 10 elderly, and 16 non-elderly participants. Visual assessment is used as the gold standard for PPG signal quality, with inter-rater agreement evaluated using Fleiss' Kappa. With this gold standard, 5 classifiers were evaluated using a modified 13-fold cross-validation approach. Main results A Random Forest quality classification algorithm showed the best performance, with an accuracy of 74.5%, and was then used to evaluate 24 h long ambulatory wrist-based PPG measurements. Significance In general, data quality was high at night, and low during the day. Our results suggest wrist-based PPG may be best for continuous cardiovascular monitoring applications during the night, but less useful during the day unless methods can be identified to improve low quality signal segments.
23 citations
Cites methods from "A novel sensor for wrist based opti..."
...[10] Other researchers have proposed methods using different wavelengths of light, such as the yellow-orange spectrum [11]....
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14 May 2018
TL;DR: Early results show that an off the shelf system targeted for residential security and home automation applications based on low-cost sensors supported with automated analysis and classification has the potential to be used to assist caregivers and dementia patients.
Abstract: The measurement and detection of overnight wandering is a significant issue for dementia patients and their caregivers such as a spouse The wandering places the patient at risk of injury or even death if they fall or leave their residence without being detected While it also causes stress and reduced sleep for the caregiver as they try to remain alert to the actions of their partner This paper presents initial data for the first participant from an ongoing study of dementia patients where a wander detection and diversion system based on low-cost commercial sensors has been deployed into the residence The paper shows that over a 3-week period, the analysis and classification of the sensor data is able to measure the behavior of the patient In this period, the patient only used the washroom overnight and did not wander into other parts of the residence These early results show that an off the shelf system targeted for residential security and home automation applications based on low-cost sensors supported with automated analysis and classification has the potential to be used to assist caregivers and dementia patients
22 citations
Cites methods from "A novel sensor for wrist based opti..."
...Alternative methods of measuring cognitive decline through EEG/ERP based tests have been presented [18] along with sensor systems to provide ongoing monitoring of vital signs [19]....
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References
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TL;DR: Photoplethysmography is a simple and low-cost optical technique that can be used to detect blood volume changes in the microvascular bed of tissue and is often used non-invasively to make measurements at the skin surface.
Abstract: Photoplethysmography (PPG) is a simple and low-cost optical technique that can be used to detect blood volume changes in the microvascular bed of tissue. It is often used non-invasively to make measurements at the skin surface. The PPG waveform comprises a pulsatile ('AC') physiological waveform attributed to cardiac synchronous changes in the blood volume with each heart beat, and is superimposed on a slowly varying ('DC') baseline with various lower frequency components attributed to respiration, sympathetic nervous system activity and thermoregulation. Although the origins of the components of the PPG signal are not fully understood, it is generally accepted that they can provide valuable information about the cardiovascular system. There has been a resurgence of interest in the technique in recent years, driven by the demand for low cost, simple and portable technology for the primary care and community based clinical settings, the wide availability of low cost and small semiconductor components, and the advancement of computer-based pulse wave analysis techniques. The PPG technology has been used in a wide range of commercially available medical devices for measuring oxygen saturation, blood pressure and cardiac output, assessing autonomic function and also detecting peripheral vascular disease. The introductory sections of the topical review describe the basic principle of operation and interaction of light with tissue, early and recent history of PPG, instrumentation, measurement protocol, and pulse wave analysis. The review then focuses on the applications of PPG in clinical physiological measurements, including clinical physiological monitoring, vascular assessment and autonomic function.
2,836 citations
TL;DR: An integrated review of the transfer of optical radiation into human skin is presented, aimed at developing useful models for photomedicine.
2,499 citations
"A novel sensor for wrist based opti..." refers background in this paper
...Anderson and Parrish [8] examined the characteristics of skin and projected that the 978-1-5090-3596-0/17/$31.00 ©2017 IEEE melanin content in skin absorbs wavelength in the regions 350 - 1200 nm....
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...Relation between melanin and HbO2 absorption coefficient and wavelength[8]....
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...The factors that affect the quality of signal from the measurement site are largely determined by the optical properties of skin [8] as well as the sensor....
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...Anderson and Parrish [8] examined the characteristics of skin and projected that the This full text paper was peer-reviewed at the direction of IEEE Instrumentation and Measurement Society prior to the acceptance and publication....
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21 Feb 2007
704 citations
"A novel sensor for wrist based opti..." refers methods in this paper
...Photoplethysmography (PPG) is a technique to measure blood volume change and provides a direct indication of several cardiological parameters [3]....
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06 Nov 2014
TL;DR: Evaluated accuracy of two PPG based HR monitors during exercise indicated that performance of devices depends on various parameters, including specified activity, sensor type and device placement.
Abstract: Wearable monitoring of heart rate (HR) during physical activity and exercising allows real time control of exercise intensity and training effect. Recently, technologies based on pulse plethysmography (PPG) have become available for personal health management for consumers. However, the accuracy of these monitors is poorly known which limits their application. In this study, we evaluated accuracy of two PPG based (wrist i.e. Mio Alpha vs forearm i.e. Schosche Rhythm) commercially available HR monitors during exercise. 21 healthy volunteers (15 male and 6 female) completed an exercise protocol which included sitting, lying, walking, running, cycling, and some daily activities involving hand movements. HR estimation was compared against values from the reference electrocardiogram (ECG) signal. The heart rate estimation reliability scores for <;5% accuracy against reference were following: mio Alpha 77,83% and Scosche Rhytm 76,29%. The estimated results indicate that performance of devices depends on various parameters, including specified activity, sensor type and device placement.
133 citations
"A novel sensor for wrist based opti..." refers background in this paper
...It has been found that sensor characteristics and placement play a crucial role in picking up optimum signal quality from the dorsal side of the wrist where the wearable is usually preferred to be worn, since its form factor resembles that of a watch [5]....
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Book•
01 Jan 2014
TL;DR: This book provides the first comprehensive resource of all currently used wearable devices in an accessible and structured manner and helps engineers manufacture wearable devices with information on current technologies, with a focus on end user needs and recycling requirements.
Abstract: Written by industry experts, this book aims to provide you with an understanding of how to design and work with wearable sensors. Together these insights provide the first single source of information on wearable sensors that would be a valuable addition to the library of any engineer interested in this field. Wearable Sensors covers a wide variety of topics associated with the development and application of various wearable sensors. It also provides an overview and coherent summary of many aspects of current wearable sensor technology. Both industry professionals and academic researchers will benefit from this comprehensive reference which contains the most up-to-date information on the advancement of lightweight hardware, energy harvesting, signal processing, and wireless communications and networks. Practical problems with smart fabrics, biomonitoring and health informatics are all addressed, plus end user centric design, ethical and safety issues. * Provides the first comprehensive resource of all currently used wearable devices in an accessible and structured manner.* Helps engineers manufacture wearable devices with information on current technologies, with a focus on end user needs and recycling requirements.* Combines the expertise of professionals and academics in one practical and applied source.
116 citations
"A novel sensor for wrist based opti..." refers background in this paper
...It is found that the signal quality for PPG signals from non-peripheral measurement sites is optimum for the green wavelength [9] and it is proven that green is superior to Infra-Red [6]....
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