Wearable Units

Tamura, Toshiyo

doi:10.1007/978-3-319-69362-0_8

Cited by 11 publications

(7 citation statements)

References 155 publications

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“…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.…”

Section: Resultssupporting

confidence: 63%

Optical Fibre-Based Pulse Oximetry Sensor with Contact Force Detection

Liu¹,

Correia²,

Ballaji³

et al. 2018

Sensors

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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.

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Section: Resultssupporting

confidence: 63%

Optical Fibre-Based Pulse Oximetry Sensor with Contact Force Detection

Liu¹,

Correia²,

Ballaji³

et al. 2018

Sensors

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“…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].…”

Section: Discussionmentioning

confidence: 99%

“…In recent years, the development of new non-invasive methods and systems such as PPG, optical spectroscopy, and pulse oximetry have improved HR measurements during exercise [51,52]. Wrist-worn devices for activity and human resources monitoring have become increasingly popular, and can help motivate athletes or patients [53].…”

Section: Introductionmentioning

confidence: 99%

Are Activity Wrist-Worn Devices Accurate for Determining Heart Rate during Intense Exercise?

et al. 2023

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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.

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“…Moreover, as the electrodes also convert ionic into electron current, 35 not only the electrode material and geometry affect the signal acquisition, but also their position. 36,37 …”

Section: Fundamentals Of Electrocardiography – Overview and Requireme...mentioning

confidence: 99%