Photoplethysmography Enabled Wearable Devices and Stress Detection: A Scoping Review

Abstract

Background: Mental and physical health are both important for overall health. Mental health includes emotional, psychological, and social well-being; however, it is often difficult to monitor remotely. The objective of this scoping review is to investigate studies that focus on mental health and stress detection and monitoring using PPG-based wearable sensors. Methods: A literature review for this scoping review was conducted using the PRISMA (Preferred Reporting Items for the Systematic Reviews and Meta-analyses) framework. A total of 290 studies were found in five medical databases (PubMed, Medline, Embase, CINAHL, and Web of Science). Studies were deemed eligible if non-invasive PPG-based wearables were worn on the wrist or ear to measure vital signs of the heart (heart rate, pulse transit time, pulse waves, blood pressure, and blood volume pressure) and analyzed the data qualitatively. Results: Twenty-three studies met the inclusion criteria, with four real-life studies, eighteen clinical studies, and one joint clinical and real-life study. Out of the twenty-three studies, seventeen were published as journal-based articles, and six were conference papers with full texts. Because most of the articles were concerned with physiological and psychological stress, we decided to only include those that focused on stress. In twelve of the twenty articles, a PPG-based sensor alone was used to monitor stress, while in the remaining eight papers, a PPG sensor was used in combination with other sensors. Conclusion: The growing demand for wearable devices for mental health monitoring is evident. However, there is still a significant amount of research required before wearable devices can be used easily and effectively for such monitoring. Although the results of this review indicate that mental health monitoring and stress detection using PPG is possible, there are still many limitations within the current literature, such as a lack of large and diverse studies and ground-truth methods, that need to be addressed before wearable devices can be globally useful to patients.

Sensing behavior change in chronic pain: A scoping review of sensor technology for use in daily life

“…Recommendations emphasize greater involvement of experts by experience in development and testing and multiple sensor use to improve accuracy. 61 Also of relevance to pain studies is the growing interest in interoceptive awareness and its relevance for mental representation and interpretation of bodily states and experiences. This has focussed mainly on psychological disorders, exploring factors such as oxygen consumption, thermoregulation, and acoustic feedback related to heart rate during exertion.…”

“…Recommendations emphasize greater involvement of experts by experience in development and testing and multiple sensor use to improve accuracy. 61…”

“…Two reviews described strengths and shortcomings, 37,78 particularly the scarcity of studies focused on daily life contexts. Some stress studies were relevant, assessing stress by cortisol detection in sweat 76 ; photoplethysmographic methods with sensors on fingers, wrist, or earlobe 61 ; and smartphone applications for analysing speech, where changes in muscle tension and breathing affecting speech prosody are reasonably well correlated with skin conductance parameters. 81 The use of voice features to indicate psychological disorders is a burgeoning area, 78 as are social contact factors to indicate depression.…”

Feasibility of a wrist-worn wearable device for estimating mental health status in patients with mental illness

“…A recent review ( 28 ) found that 12 of the 20 studies on stress used a PPG sensor alone to monitor stress; in the remaining 8 studies, a PPG sensor was used in combination with other sensors. In general, a higher performance is achieved if a PPG sensor is used in combination with other sensors than if PPG is used alone ( 29 – 31 ).…”

AI-Enabled Smart Wristband Providing Real-Time Vital Signs and Stress Monitoring

“…For a general overview of the field, the interested reader is referred to [18][19][20], and to references therein: these constitute comprehensive and well-researched review articles, investigating stress detection approaches based on wearable sensors in the context of different tasks, such as driving, studying, working, etc. In [18], meaningful guidelines, with respect to crucial aspects of stress detection studies-such as stress elicitation, ground truth acquisition, etc.-were also identified.…”