Evaluation of mental stress by physiological indices derived from finger plethysmography

Digital Interventions to Understand and Mitigate Stress Response: Protocol for Process and Content Evaluation of a Cohort Study

BACKGROUND

Staffing and resource shortages, especially during the COVID-19 pandemic, have increased stress levels among health care workers. Many health care workers have reported feeling unable to maintain the quality of care expected within their profession, which, at times, may lead to moral distress and moral injury. Currently, interventions for moral distress and moral injury are limited.

OBJECTIVE

This study has the following aims: (1) to characterize and reduce stress and moral distress related to decision-making in morally complex situations using a virtual reality (VR) scenario and a didactic intervention; (2) to identify features contributing to mental health outcomes using wearable, physiological, and self-reported questionnaire data; and (3) to create a personal digital phenotype profile that characterizes stress and moral distress at the individual level.

METHODS

This will be a single cohort, pre- and posttest study of 100 nursing professionals in Ontario, Canada. Participants will undergo a VR simulation that requires them to make morally complex decisions related to patient care, which will be administered before and after an educational video on techniques to mitigate distress. During the VR session, participants will complete questionnaires measuring their distress and moral distress, and physiological data (electrocardiogram, electrodermal activity, plethysmography, and respiration) will be collected to assess their stress response. In a subsequent 12-week follow-up period, participants will complete regular assessments measuring clinical outcomes, including distress, moral distress, anxiety, depression, and loneliness. A wearable device will also be used to collect continuous data for 2 weeks before, throughout, and for 12 weeks after the VR session. A pre-post comparison will be conducted to analyze the effects of the VR intervention, and machine learning will be used to create a personal digital phenotype profile for each participant using the physiological, wearable, and self-reported data. Finally, thematic analysis of post-VR debriefing sessions and exit interviews will examine reoccurring codes and overarching themes expressed across participants' experiences.

RESULTS

The study was funded in 2022 and received research ethics board approval in April 2023. The study is ongoing.

CONCLUSIONS

It is expected that the VR scenario will elicit stress and moral distress. Additionally, the didactic intervention is anticipated to improve understanding of and decrease feelings of stress and moral distress. Models of digital phenotypes developed and integrated with wearables could allow for the prediction of risk and the assessment of treatment responses in individuals experiencing moral distress in real-time and naturalistic contexts. This paradigm could also be used in other populations prone to moral distress and injury, such as military and public safety personnel.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05923398; https://clinicaltrials.gov/study/NCT05923398.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/54180.

Non-invasive evaluation of autonomic responses in patients with rotator cuff tear-related nocturnal pain

[Purpose] We aimed to determine the autonomic response in patients with rotator cuff tear-related nocturnal pain using nonlinear analysis of heart rate variability. [Participants and Methods] Twenty-eight patients with nocturnal pain who were diagnosed with a rotator cuff tear and received steroid injections, and whose nocturnal pain improved, were divided into a control group (14 patients) and a failure group (14 patients). Pulse wave was measured continuously using BACS Advance equipment (TAOS Co.) for a total of 17 min: 5 min before isometric hand grip, 2 min during isometric hand grip, 5 min after isometric hand grip, and 10 min after isometric hand grip. The autonomic nervous system activity was assessed using detrended fluctuation analysis and approximate entropy. [Results] The α1 values obtained from the detrended fluctuation analysis were significantly higher in the failure group than in the control group at each measurement period. The approximate entropy was normal in 12 (85%) patients in the control group and six (42%) patients in the failure group; it was abnormal in two (15%) patients in the control group and eight (58%) patients in the failure group. [Conclusion] Among patients experiencing nocturnal pain, several have abnormal autonomic response during isometric hand grip.

Heart rate variability status at rest in adult depressed patients: a systematic review and meta-analysis

Purposes

A meta-analysis was conducted to examine the differences in heart rate variability (HRV) between depressed patients and healthy individuals, with the purpose of providing a theoretical basis for the diagnosis of depression and the prevention of cardiovascular diseases.

Methods

To search China National Knowledge Infrastructure (CNKI), WanFang, VIP, PubMed, Web of Science, Science Direct, and Cochrane Library databases to collect case-control studies on HRV in depressed patients, the retrieval date is from the establishment of the database to December 2022. Effective Public Health Practice Project (EPHPP) scale was used to evaluate literature quality, and Stata14.0 software was used for meta-analysis.

Results

This study comprised of 43 papers, 22 written in Chinese and 21 in English, that included 2,359 subjects in the depression group and 3,547 in the healthy control group. Meta-analysis results showed that compared with the healthy control group, patients with depression had lower SDNN [Hedges' g = -0.87, 95% CI (-1.14, -0.60), Z = -6.254, p < 0.01], RMSSD [Hedges' g = -0.51, 95% CI (-0.69,-0.33), Z = -5.525, p < 0.01], PNN50 [Hedges' g = -0.43, 95% CI (-0.59, -0.27), Z = -5.245, p < 0.01], LF [Hedges' g = -0.34, 95% CI (-0.55, - 0.13), Z = -3.104, p < 0.01], and HF [Hedges' g = -0.51, 95% CI (-0.69, -0.33), Z = -5.669 p < 0.01], and LF/HF [Hedges' g = -0.05, 95% CI (-0.27, 0.18), Z = -0.410, p = 0.682] showed no significant difference.

Conclusion

This research revealed that HRV measures of depressed individuals were lower than those of the healthy population, except for LF/HF, suggesting that people with depression may be more at risk of cardiovascular diseases than the healthy population.

Stress Evaluation by Hemoglobin Concentration Change Using Mobile NIRS

Previous studies have reported a relationship between stress and brain activity, and stress has been quantitatively evaluated using near-infrared spectroscopy (NIRS). In the present study, we examined whether a relationship exists between salivary amylase levels and brain activity during the trail-making test (TMT) using mobile NIRS. This study aimed to assess stress levels by using mobile NIRS. Salivary amylase was measured with a salivary amylase monitor, and hemoglobin concentration was measured using Neu’s HOT-2000. Measurements were taken four times for each subject, and the values at each measurement were evaluated. Changes in the values at the first–second, second–third, and third–fourth measurements were also analyzed. Results showed that the value of the fluctuations has a higher correlation than the comparison of point values. These results suggest that the accuracy of stress assessment by NIRS can be improved by using variability and time-series data compared with stress assessment using NIRS at a single time point.

Psychological and Antibacterial Effects of Footbath Using the Lindera umbellata Essential Oil

Lindera umbellata (Lu) essential oil primarily contains linalool and has relaxation properties. We investigated the psychological and antibacterial effects of footbath with Lu essential oil. The participants included 20 women without medical history and received two intervention plans: footbath without any essential oil and footbath using Lu essential oil. Next, questionnaires regarding impressions and mood states were provided for them to answer. In addition, their autonomic nervous system activity was measured, and the aerobic viable of count on the feet was determined. The high-frequency value reflecting the parasympathetic nervous system activity significantly increased after footbath using Lu essential oil. In the questionnaire about the mood states, the subscale scores of tension–anxiety, depression, fatigue, and confusion after intervention were lower than those before intervention regardless of the use of the essential oil. Conversely, the anger–hostility score decreased only in the group using Lu essential oil. Furthermore, the decrease in aerobic viable count after intervention was not significantly different between the two groups. Footbath using Lu essential oil increased the parasympathetic nervous system activity and relieved anger. Taken together, we suggest that footbath using Lu essential oil has a relaxation effect.

A Muscular and Cerebral Physiological Indices Assessment for Stress Measuring during Virtual Wheelchair Guidance

The work presented in this manuscript has the purpose to assess the relationship between human factors and physiological indices. We discuss the relationship between stress as human factor and cerebral and muscular signals as features. Ten male paraplegic, right-handed subjects were volunteers for the experiment (mean age 34 ±6). They drove a virtual wheelchair in an indoor environment. They filled five missions where, in each one, an environmental parameter was changed. Meanwhile, they were equipped with Electromyography (EMG) sensors and Electroencephalography (EEG). Frequency and temporal features were filtered and extracted. Principal component analysis (PCA), Fisher's tests, repeated measure Anova and post hoc Tukey test (α = 0.05) were implemented for statistics. Environmental modifications are subject to induce stress, which impacts muscular and cerebral activities. While the time pressure parameter was the most influent, the transition from static to moving obstacles (avatars), tends to have a significant impact on stress levels. However, adding more moving obstacles did not show any impact. A synchronization factor was noticed between cerebral and muscular features in higher stress levels. Further examination is needed to assess EEG reliability in these situations.

Influence of mental stress on the pulse wave features of photoplethysmograms

Mental stress is a major burden for our society. Invasive and non-invasive methods have been proposed to monitor and quantify it using various sensors on and off body. In this Letter, the authors investigated the use of the arm photoplethysmogram (PPG) to assess mental stress in laboratory conditions. Results were in correspondence with their previous in-silico study which guided the present study. Three wave shape parameters were identified for stress assessment from the PPG signal: (i) the time from dicrotic notch to end diastole; (ii) the time from pulse onset to systolic peak; and (iii) the ratio of diastolic to systolic area. The proposed in-vivo results showed that the two first parameters responded significantly to increased mental stress and to a breathing relaxation procedure, complementing heart rate, heart rate variability, and pulse transit time as indices of stress.

Chilliness in Japanese middle-aged women is associated with anxiety and low n-3 fatty acid intake

Objective: This cross-sectional study investigated chilliness, which is the most prevalent sexual-vasomotor symptom in middle-aged Japanese women.Methods: First-visit records of 475 Japanese women (age 40-65 years) enrolled in the health and nutrition education program at a menopause clinic were analyzed. Chilliness was estimated based on responses to the Menopausal Symptom Scale. Effects of age, menopausal status, body composition, cardiovascular parameters, resting energy expenditure, physical fitness, menopausal symptoms, lifestyle, and estimated daily intake of nutrients were assessed using a multivariate logistic regression analysis.Results: Severe chilliness was found in 28.4% of women. It was not related to age, menopausal status, body mass index, or body fat percentage. The anxiety subscale score of the Hospital Anxiety and Depression Scale was the sole background characteristic independently associated with severe chilliness (adjusted odds ratio, 1.09; 95% confidence interval, 1.04-1.15 per point). Daily intakes of vitamin D and n-3 fatty acids were significantly lower in women with severe chilliness. Daily intake of n-3 fatty acids was negatively associated with severe chilliness after adjustment (odds ratio, 0.54; 95% confidence interval, 0.29-0.95 per g/1000 kcal intake).Conclusions: Chilliness is associated with anxiety and low intake of n-3 fatty acids.

Stress response in the daily lives of simulation repeaters. A randomized controlled trial assessing stress evolution over one year of repetitive immersive simulations

BACKGROUND

Simulations in healthcare reproduce clinical situations in stressful conditions. Repeated stress exposure might influence the learning process in simulation as well as real-life.

OBJECTIVES

1) To record heart rate and heart rate variability evolution during one-day simulation over one year; 2) To analyze the effect of repetitive high-fidelity simulations on the risk of post-traumatic stress disorder.

STUDY DESIGN

Single-center, investigator-initiated RCT. 48 participants were randomized in 12 multidisciplinary teams of French Emergency Medical Services to manage infant shock in high-fidelity simulations. In the experimental group, 6 multidisciplinary teams were exposed to 9 different simulation sessions over 1 year. In the control group, 6 multidisciplinary teams participated in only 3 simulation sessions, in common with those of the experimental group (initial, intermediate after 6 months, and finally after 1 year). Heart rate (HR) and heart rate variability (HRV) were analyzed on a 24-hour Holter from the day prior to simulation until the end of simulation. Questionnaires of Impact of Event Scale-Revised at 7 days and Post-traumatic Check-List Scale at 1 month were used to detect possible post-traumatic stress disorder in participants. p<0.05 was considered significant.

RESULTS

Stress increased during each simulation in the two groups. After analysis on the 24-hour period, there was no significant difference between the two groups during the initial simulation session in terms of heart rate and heart rate variability. In the 24-hour period of the intermediate and final simulation sessions, the level of stress was higher in the control group during the diurnal (p = 0.04) and nocturnal periods (p = 0.01). No participant developed post-traumatic stress disorder after the 72 simulation sessions.

CONCLUSIONS

Despite the stress generated by simulation, the more the sessions were repeated, the less were their repercussions on the daily lives of participants, reflected by a lower sympathetic activity. Moreover, repetition of simulations did not lead to post-traumatic stress disorder.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02424890.

Ultra-short term HRV features as surrogates of short term HRV: a case study on mental stress detection in real life

Background

This paper suggests a method to assess the extent to which ultra-short Heart Rate Variability (HRV) features (less than 5 min) can be considered as valid surrogates of short HRV features (nominally 5 min). Short term HRV analysis has been widely investigated for mental stress assessment, whereas the validity of ultra-short HRV features remains unclear. Therefore, this study proposes a method to explore the extent to which HRV excerpts can be shortened without losing their ability to automatically detect mental stress.

Methods

ECGs were acquired from 42 healthy subjects during a university examination and resting condition. 23 features were extracted from HRV excerpts of different lengths (i.e., 30 s, 1 min, 2 min, 3 min, and 5 min). Significant differences between rest and stress phases were investigated using non-parametric statistical tests at different time-scales. Features extracted from each ultra-short length were compared with the standard short HRV features, assumed as the benchmark, via Spearman’s rank correlation analysis and Bland-Altman plots during rest and stress phases. Using data-driven machine learning approaches, a model aiming to detect mental stress was trained, validated and tested using short HRV features, and assessed on the ultra-short HRV features.

Results

Six out of 23 ultra-short HRV features (MeanNN, StdNN, MeanHR, StdHR, HF, and SD2) displayed consistency across all of the excerpt lengths (i.e., from 5 to 1 min) and 3 out of those 6 ultra-short HRV features (MeanNN, StdHR, and HF) achieved good performance (accuracy above 88%) when employed in a well-dimensioned automatic classifier.

Conclusion

This study concluded that 6 ultra-short HRV features are valid surrogates of short HRV features for mental stress investigation.

Electronic supplementary material

The online version of this article (10.1186/s12911-019-0742-y) contains supplementary material, which is available to authorized users.

A novel cross-correlation methodology for assessing biophysical responses associated with pain

Purpose

The purpose of this work was to noninvasively detect and quantify microvascular blood flow changes in response to externally applied pain in humans. The responsiveness of the microvasculature to pain stimulation might serve as an objective biomarker in diseases associated with altered pain perception and dysregulated vascular functions. The availability of such a biomarker may be useful as a tool for predicting outcome and response to treatments, particularly in diseases like sickle cell anemia where clinical manifestations are directly linked to microvascular perfusion. We, therefore, developed a method to distinguish the blood flow response due to the test stimulus from the blood flow measurement that also includes concurrent flow changes from unknown origins.

Subjects and methods

We measured the microvascular blood flow response in 24 healthy subjects in response to a train of randomly spaced and scaled heat pulses on the anterior forearm. The fingertip microvascular perfusion was measured using laser Doppler flowmetry. The cross-correlation between the heat pulses and the blood flow response was computed and tested for significance against the null distribution obtained from the baseline recording using bootstrapping method.

Results

We estimated correlation coefficients, response time, response significance, and the magnitude of vasoreactivity from microvascular blood flow responses. Based on these pain response indices, we identified strong responders and subjects who did not show significant responses.

Conclusion

The cross-correlation of a random pattern of painful stimuli with directly measured microvascular flow can detect vasoconstriction responses in a noisy blood flow signal, determine the time between stimulus and response, and quantify the magnitude of this response. This approach provided an objective measurement of vascular response to pain that may be an inherent characteristic of individual human subjects, and may also be related to the severity of vascular disorders.

Objective detection of chronic stress using physiological parameters

The aim of this study was to design a system to diagnose chronic stress, based on blunted reactivity of the autonomic nervous system (ANS) to cognitive load (CL). The system concurrently measures CL-induced variations in pupil diameter (PD), heart rate (HR), pulse wave amplitude (PWA), galvanic skin response (GSR), and breathing rate (BR). Measurements were recorded from 58 volunteers whose stress level was identified using the State-Trait Anxiety Inventory. Number-multiplication questions were used as CLs. HR, PWA, GSR, and PD were significantly (p < 0.05) changed during CL. CL-induced changes in PWA (16.87 ± 21.39), GSR (- 13.71 ± 7.86), and PD (11.56 ± 9.85) for non-stressed subjects (n = 36) were significantly different (p < 0.05) from those in PWA (2.92 ± 12.89), GSR (- 6.87 ± 9.54), and PD (4.51 ± 10.94) for stressed subjects (n = 22). ROC analysis for PWA, GSR, and PD illustrated their usefulness to identify stressed subjects. By inputting all features to different classification algorithms, up to 91.7% of sensitivity and 89.7% of accuracy to identify stressed subjects were achieved using 10-fold cross-validation. This study was the first to document blunted CL-induced changes in PWA, GSR, and PD in stressed subjects, compared to those in non-stressed subjects. Preliminary results demonstrated the ability of our system to objectively detect chronic stress with good accuracy, suggesting the potential for monitoring stress to prevent dangerous stress-related diseases. Graphical abstract Chronic stress degrads the autonomic nervous system reaction to cognitive loads. Measurement of reduced changes in physiological signals during asking math questions was useful to identify people with high STAI score (stressed subjects).

Lower amputation rate after fasciotomy by straight midline incision technique for a 22,900-V electrical injury to the upper extremities

PURPOSE

The purpose of this study is to compare the major amputation rate following two different fasciotomy techniques, conventional versus straight midline, in patients with high-voltage arc burn injury by electric currents of 22,900V to the upper extremities.

METHODS

A retrospective analysis of 230 patients (270 burned upper limbs) who underwent fasciotomy after high-voltage electrical injuries between 1996 and 2007 was performed. The patients were divided into two groups according to the fasciotomy method used. From 1996 to 2002, 158 patients (184 limbs) underwent conventional fasciotomy by Green's volar-ulnar incision (conventional fasciotomy group). From 2003 to 2007, 72 patients (86 limbs) underwent fasciotomy using a straight midline curved incision (midline fasciotomy group). The patients were also divided into two groups based on whether the fasciotomy procedure was performed early or late. Patients who underwent fasciotomies <8h after injury were classified as early, while those who underwent it >8h after injury were classified as late. Major amputation rates were compared between two fasciotomy methods and analyzed following fasciotomy timing.

RESULTS

The midline fasciotomy group had a significantly lower major amputation rate (33.7%) than the conventional fasciotomy group (59.2%) (p<0.001). A subsequently decreased major amputation rate of 27.8% was observed in the early fasciotomy subgroup of the midline fasciotomy group (p=0.025).

CONCLUSION

Early fasciotomy remarkably reduced the major amputation rate after high-voltage arc injury; in the setting of minimized vascular exposure after fasciotomy, a midline straight incision could ensure that various types of reconstructive microsurgical procedures and primary skin closures can be used to save limbs.

The effect of time pressure on stress levels during virtual wheelchair navigation

In this work stress is assessed based on EEG features. We focus our efforts on the correlation between subjective ratings and cerebral indices during virtual navigation scenarios. Ten male paraplegic subjects took part in the experiment and navigated in a virtual indoor environment. They had to fulfill two missions where time pressure parameter is introduced. Subjects were equipped with Electroencephalography sensors. Temporal and frequency data were filtered and extracted. A correlation study was conducted based on principal component analysis, Fisher's tests and ANOVA. The results showed that the introduction of time pressure has a significant impact on stress levels.

Evaluation of stress response using psychological, biological, and electrophysiological markers during immersive simulation of life threatening events in multidisciplinary teams

Stress might impair clinical performance in real life and in simulation-based education (SBE). Subjective or objective measures can be used to assess stress during SBE. This monocentric study aimed to evaluate the effects of simulation of life-threatening events on measurements of various stress parameters (psychological, biological, and electrophysiological parameters) in multidisciplinary teams (MDTs) during SBE. The effect of gender and status of participants on stress response was also investigated. Twelve emergency MDTs of 4 individuals were recruited for an immersive simulation session. Stress was assessed by: (1) self-reported stress; (2) Holter analysis, including heart rate and heart rate variability in the temporal and spectral domain (autonomic nervous system); (3) salivary cortisol (hypothalamic pituitary adrenal axis). Forty-eight participants (54.2% men, <7years of experience) were included. Measures were performed at baseline (T0), after simulation (T1), after debriefing (T2), and 30min after debriefing (T3). There was an increase in stress level at T1 (p<0.001) and a decrease at T2 (p<0.001). However, the variations of stress parameters induced by simulation (T0-T1 difference and T1-T2 difference) estimated by the three approaches were not correlated, while, as expected, Holter parameters were well-correlated to each other. Immersive SBE produced a change of stress level in all MDT members with no evidence for status effect but with gender difference. None developed a PTSD. These results support the hypothesis of a complementarity of the stress paths (collective reaction with increased stress level during simulation and a decrease during debriefing) but with relative independence of these paths (lack of correlation to each other). This study also suggests that because of the lack of correlation, stress response should be assessed by a combination of psychological, biological and electrophysiological parameters.

AUTOMATIC HUMAN STRESS DETECTION BASED ON WEBCAM PHOTOPLETHYSMOGRAPHIC SIGNALS

One of the goals of affective computing field is to provide to computers the ability to recognize automatically the affective state of the user in order to have more intuitive human–machine communication. This paper aims to detect automatically the stress user when he is interacting with computer. The developed system is based on instantaneous pulse rate (PR) signal extracted from imaging photoplethysmography (PPG). Seven features from time and frequency domain are extracted from PR signal and processed by learning pattern recognition systems. Two methods based on Support Vector Machine (SVM) and Linear Discriminant Analysis (LDA) are used and compared to classify the user’s emotional state. A computer application based on “Stroop color word Test” is developed to elicit emotional stress in the subject. The proposed method can achieve the overall average classification accuracy of 94.42% and 91.10% with SVM and LDA, respectively. Current results indicate that our approach is effective for stress classification.

Impact of a motivated performance task on autonomic and hemodynamic cardiovascular reactivity

Motivated performance (MP) tasks include mental stressors characterized by a high degree of motivation, individual engagement, and sympathetic overstimulation. It is therefore important to document the independent influence of motivation apart from engagement on markers of cardiovascular autonomic modulation, including vasomotor tone (low-frequency systolic blood pressure, LFSBP), blood pressure homeostasis (baroreflex sensitivity, BRS), and myocardial oxygen consumption (rate pressure product, RPP). Accordingly, an arithmetic task (AT) was used to manipulate motivation to evaluate its impact on cardiovascular reactivity. Forty-two young adults (Mage = 20.21 years, SD = 2.09) qualified for the study. After a 10-min resting period, electrocardiogram and finger beat-to-beat blood pressure were recorded at three distinct 5-min stages: baseline (BASE), AT, and recovery (REC). Prior to AT initiation, participants were randomized into two groups based on directions stating that the AT task was either designed to be entertaining and fun (low MP, LMP) or a test diagnostic of one's intelligence (high MP, HMP). Independent of task engagement ratings, motivation to complete the AT task as well as solution success was significantly greater in the HMP than the LMP condition. Regarding physiological parameters, two (LMP vs. HMP) × three (BASE, AT, REC) repeated measures ANOVAs revealed no significant baseline differences but a significant higher order interaction indicating that in comparison to LMP, individuals in the HMP condition had significantly higher vasomotor tone and myocardial oxygen consumption but not BRS. Greater motivation during a performance task may provide the substrate for the development of adverse cardiovascular events by increasing sympathetic activity and ultimately increasing myocardial oxygen demand which could lead to acute coronary syndromes.

Computerized assessment of communication for cognitive stimulation for people with cognitive decline using spectral-distortion measures and phylogenetic inference

Therapeutic communication and interpersonal relationships in care homes can help people to improve their mental wellbeing. Assessment of the efficacy of these dynamic and complex processes are necessary for psychosocial planning and management. This paper presents a pilot application of photoplethysmography in synchronized physiological measurements of communications between the care-giver and people with dementia. Signal-based evaluations of the therapy can be carried out using the measures of spectral distortion and the inference of phylogenetic trees. The proposed computational models can be of assistance and cost-effectiveness in caring for and monitoring people with cognitive decline.