This study presents the use of a multi-channel opto-electronic sensor (OEPS) to effectively monitor critical physiological parameters whilst preventing motion artefact as increasingly demanded by personal healthcare. The aim of this work was to study how to capture the heart rate (HR) efficiently through a well-constructed OEPS and a 3-axis accelerometer with wireless communication. A protocol was designed to incorporate sitting, standing, walking, running and cycling. The datasets collected from these activities were processed to elaborate sport physiological effects. t-test, Bland-Altman Agreement (BAA), and correlation to evaluate the performance of the OEPS were used against Polar and Mio-Alpha HR monitors. No differences in the HR were found between OEPS, and either Polar or Mio-Alpha (both p > 0.05); a strong correlation was found between Polar and OEPS (r: 0.96, p < 0.001); the bias of BAA 0.85 bpm, the standard deviation (SD) 9.20 bpm, and the limits of agreement (LOA) from −17.18 bpm to +18.88 bpm. For the Mio-Alpha and OEPS, a strong correlation was found (r: 0.96, p < 0.001); the bias of BAA 1.63 bpm, SD 8.62 bpm, LOA from −15.27 bpm to +18.58 bpm. These results demonstrate the OEPS to be capable of carrying out real time and remote monitoring of heart rate.
Different skin pigments among various ethnic group people have an impact on spectrometric illumination on skin surface. To effectively capture photoplethysmographic (PPG) signals, a multi-wavelength opto-electronic patch sensor (OEPS) together with a schematic architecture of electronics were developed to overcome the drawback of present PPG sensor. To perform a better in vivo physiological measurement against skin pigments, optimal illuminations in OEPS, whose wavelength is compatible with a specific skin type, were optimized to capture a reliable physiological sign of heart rate (HR). A protocol was designed to investigate an impact of five skin types in compliance with Von Luschan’s chromatic scale. Thirty-three healthy male subjects between the ages of 18 and 41 were involved in the protocol implemented by means of the OEPS system. The results show that there is no significant difference (p: 0.09, F = 3.0) in five group tests with the skin types across various activities throughout a series of consistent measurements. The outcome of the present study demonstrates that the OEPS, with its multi-wavelength illumination characteristics, could open a path in multiple applications of different ethnic groups with cost-effective health monitoring.
17 October 2019 in IEEE Instrumentation & Measurement Magazine
Poor air quality is considered among the main causes of millions of premature deaths annually, about 8 million in 2012 according to the World Health Organization [1]. Several epidemiological studies have found a relationship between exposure beyond specified limits and burden of disease [2]. These and many more have led to an increased and urgent need to both monitor and consequently limit personal exposure to harmful pollutants [3]. There is a generalized attention from different governmental agencies globally to limit anthropogenic emissions via legislations and policies. City councils, including for instance in Cambridge, UK, promote new policies that help accelerate switching from combustion engines to electric vehicles both for public and for private transport, accompanied by installation of a distributed urban network of rapid charging points by 2020 [4], along with imposition of road taxes, and exemption from the same based on vehicles' emission of polluting gases and smaller particulate matter (PM2.5). Besides, reduction of indoor wood burning for heating, as one of the largest sources of indoor particulate matter, also has the potential to drastically reduce PM2.5 exposure levels. Citizens are nowadays more conscious of and attentive to their personal exposure to polluting agents and environments and prone to adopt cleaner solutions for living, transport, energy generation and heating. Adoption of personal exposure monitoring devices on an individual level therefore offers multiple benefits and is motivated by the willingness to continue making healthier choices in everyday life consistently. Access to high resolution data of personal exposure with high space and time accuracy is however difficult to achieve with currently available centralized or public network of monitoring stations. Providing individuals with portable devices for air quality monitoring that operate in real time and allow them to monitor and record their personalized exposure levels in combination with conventional geolocation offering a half-meter or less space resolution may become a unique instrument and breakthrough, not only for the individuals, but also for the city councils, and other government agencies to shape and fine-tune their policies for control of air quality in urban, industrial and rural areas. This is possible with the use of both existing and emerging technologies for autonomous sensors, data communication and modern mobile networks, including Internet of Things.
This paper presents a comparative study in physiological monitoring between a wearable opto-electronic patch sensor (OEPS) comprising a three-axis Microelectromechanical systems (MEMs) accelerometer (3MA) and commercial devices. The study aims to effectively capture critical physiological parameters, for instance, oxygen saturation, heart rate, respiration rate and heart rate variability, as extracted from the pulsatile waveforms captured by OEPS against motion artefacts when using the commercial probe. The protocol involved 16 healthy subjects and was designed to test the features of OEPS, with emphasis on the effective reduction of motion artefacts through the utilization of a 3MA as a movement reference. The results show significant agreement between the heart rates from the reference measurements and the recovered signals. Significance of standard deviation and error of mean yield values of 2.27 and 0.65 beats per minute, respectively; and a high correlation (0.97) between the results of the commercial sensor and OEPS. T, Wilcoxon and Bland-Altman with 95% limit of agreement tests were also applied in the comparison of heart rates extracted from these sensors, yielding a mean difference (MD: 0.08). The outcome of the present work incites the prospects of OEPS on physiological monitoring during physical activities.
This paper presents a non-invasive and wearable optical technique to monitor physiological assessment by means of photoplethysmography (PPG). The study aims to research into an effective way to capture human critical physiological parameters, i.e. oxygen saturation (SaO2%), heart rate, respiration rate through a well contracted and wearable patch probe together with a real-time and secure wireless communication functionalities. The work presents the first step of this research; an automatic noise cancellation method using a 3-axes MEMS accelerometer to recover signals corrupted by body movement as one of the biggest sources of motion artefacts. These kinds of motion artefacts could be reduced by an appropriate electronic design and development for self-cancellation noise and stability of the sensor. The signals from the acceleration and the PPG sensor are highly correlated thus the desire PPG signals retrieved with reduced motion artefacts. The preliminary results from the bench tests and the laboratory setup demonstrate that the goal of the high performance wearable PPG is viable and feasible.
Air pollution causes premature deaths and increased infant mortality. [1] Particulate Matter smaller than 2.5μm in aerodynamic diameter (PM2.5) exposure has been found to be the cause of airway inflammation and other adverse effects. [2] , [3] Recent studies have shown that vehicular emissions are even more harmful for children on the roadside. [4] In fact, personal exposure has been found to be dependent on routes taken and transport modes. [5] Hence, air pollution mitigation strategies must be adapted in each location based on the emission sources. [6] A study in Brazil has estimated 400 - 1700 premature deaths to have been prevented by reducing deforestation, an important source of PM2.5. [7] This approach requires the use of portable sensors to provide high resolution data than obtained in stationary stations. However, smaller sensors are less accurate than the bulky static detectors. [8] Most commercially available portable PM sensors are based on light. But there has been problems with unit to unit deviation and inaccurate measurements. [9] Hence there is a need for portable, yet accurate PM sensors suitable for personal exposure monitoring.