Heart Rate Variability (HRV) and Posttraumatic Stress Disorder (PTSD): A Pilot Study

Cardiac coherence and medical hypnosis: a feasibility study of a new combined approach for managing preoperative anxiety in patients with breast or gynaecological cancer

Background

Non-pharmaceutical approaches can help manage preoperative anxiety, but few studies have evaluated psychoeducational programmes, especially for cancer surgery. We assessed the feasibility of the COHErence Cardiaque (COHEC) programme where cardiac coherence and medical hypnosis are combined to manage preoperative anxiety in patients undergoing breast or gynaecological cancer surgical interventions (BGCSI).

Methods

Patients undergoing BGCSI were enrolled and followed a daily home programme with cardiac coherence and medical hypnosis sessions, starting 7 days before the procedure. The primary endpoint was optimal patient adherence (i.e. completion of ≥14 sessions). Secondary endpoints were anxiety levels, measured using the Visual Analogue Scale (VAS) and the Amsterdam Preoperative Anxiety and Information Scale (APAIS), satisfaction (EVAN-G), and quality of postoperative recovery (QoR-15).

Results

In total, 53 patients [mean age: 55 (34-82) yr] were included; 83.7% had breast cancer and 15.1% had gynaecological cancer. Optimal adherence was achieved by 64.2% (95% confidence interval: 49.8-76.9%) of the intention-to-treat population. Among the 43 patients who completed at least one session, exploratory analysis showed that anxiety on the day before (P=0.02) and the morning of the intervention (P=0.04) was decreased in patients with severe anxiety at baseline (VAS ≥70). The median VAS satisfaction score for the programme was 10 (4-10). Overall, 94% of patients were willing to include the COHEC programme in their daily routine.

Conclusions

The implementation of a psychoeducational programme combining cardiac coherence and medical hypnosis is feasible and might potentially help patients undergoing BGCSI to manage preoperative anxiety. A randomised trial is underway to assess the efficacy of the COHEC programme.

Clinical trial registration

NCT03981731.

Heart rate variability impairment during sleep in Veterans with REM sleep behavior disorder, traumatic brain injury, and posttraumatic stress disorder: An early potential window into autonomic dysfunction?

Individuals with comorbid REM sleep behavior disorder (RBD) and neurotrauma (defined by traumatic brain injury and post-traumatic stress disorder) have an earlier age of RBD symptom onset, increased RBD-related symptom severity and more neurological features indicative of prodromal synucleinopathy compared to RBD only. An early sign of neurodegenerative condition is autonomic dysfunction, which we sought to evaluate by examining heart rate variability during sleep. Participants with overnight polysomnography were recruited from the VA Portland Health Care System. Veterans without neurotrauma or RBD (controls; n=19), with RBD only (RBD, n=14), and with RBD and neurotrauma (RBD+NT, n=19) were evaluated. Eligible 5-minute NREM and REM epochs without apneas/hypopneas, microarousals, and ectopic beats were analyzed for frequency and time domain (e.g. low frequency power, LF; high frequency power, HF; root mean square of successive RR intervals, RMSSD; % of RR intervals that vary ≥50 ms, pNN50) heart rate variability outcomes. Heart rate did not significantly differ between groups in any sleep stage. Time domain and frequency domain variables (e.g., LF power, HF power, RMSSD, and pNN50) were significantly reduced in the RBD and RBD+NT groups compared to controls and RBD only during NREM sleep. There were no group differences detected during REM sleep. These data suggest significant reductions in heart rate variability during NREM sleep in RBD+NT participants, suggesting greater autonomic dysfunction compared to controls or RBD alone. Heart rate variability during sleep may be an early, promising biomarker, yielding mechanistic insight for diagnosis and prognosis of early neurodegeneration in this vulnerable population.

STATEMENT OF SIGNIFICANCE

Comorbid REM sleep behavior disorder (RBD) and neurotrauma (NT, traumatic brain injury + post-traumatic stress disorder; RBD+NT) is associated with increased neurodegenerative symptom burden and worsened health. Sleep and autonomic function are integrally and bidirectionally related to neurodegenerative processes. In the current study, we sought to determine if early signs of autonomic dysfunction, measured via heart rate variability (HRV), were present during sleep in comorbid RBD+NT compared to RBD only and controls. Our data show reduced time and frequency domain HRV during NREM sleep in RBD+NT Veterans compared to RBD only and controls. These data contribute evidence that participants with RBD and comorbid NT demonstrate significantly worse autonomic dysfunction compared to age/sex matched participants with RBD alone.

Exploring autonomic dysfunction in functional dysphonia: A protocol for a case-control study and a randomized controlled trial

BACKGROUND

Although psychological factors have been implicated in patients with functional dysphonia (FD), conventional voice therapy (CVT) typically targets the aberrant voice symptoms exclusively. Yet, CVT is not always successful, and in view of the significant adverse quality of life impact combined with the financial burden on the healthcare system and society, research is needed to elucidate the underlying psychophysiology of FD and improve treatment outcomes.

OBJECTIVES

The first objective of this research project is to compare the occurrence and frequency of symptoms and/or disorders related to autonomic nervous system (ANS) dysfunction in patients with FD with gender- and age-matched vocally healthy controls, using a case-control study. The second objective is to compare the effects of a novel therapy for FD based on ANS regulation (i.e., ANS therapy: heart rate variability (HRV) biofeedback) on both autonomic function and voice function versus CVT alone or in combination with ANS therapy (i.e., ANS therapy + CVT), using a randomized controlled trial (RCT).

METHODS

Case-control study: Autonomic (dys)function of patients with FD will be compared with gender- and age-matched vocally healthy controls, using both physiological measures (e.g., HRV, skin conductance level) and psychological patient-reported outcome measures (PROMs, e.g., Neuroception of Psychological Safety Scale, Depression Anxiety and Stress Scale). RCT: The FD group will be randomly assigned to the innovative ANS therapy group, the CVT group or the ANS therapy + CVT group. All patients received 1 month of treatment with 20 min of daily practice. Both the autonomic assessment and the voice assessment will be performed pretherapy and immediately after therapy by assessors blinded to group allocation and study phase.

EXPECTED RESULTS

Higher occurrences of symptoms and/or disorders related to autonomic dysfunction are expected in patients with FD compared with vocally healthy controls. Physiological outcomes: lower HRV, lower cardiac pre-ejection period, higher respiration rate and higher skin conductance level are hypothesized in patients with FD compared with vocally healthy controls. Psychological PROMs: higher self-report of feelings/symptoms related to autonomic dysfunction (e.g., perceived stress, anxiety) is expected in patients with FD compared with vocally healthy controls. The autonomic function is hypothesized to improve more after the ANS therapy and the ANS therapy + CVT compared with the CVT only. Voice function is expected to improve more after the ANS therapy + CVT compared with the ANS therapy and the CVT alone.

WHAT THIS PAPER ADDS

What is already known on the subject Autonomic dysfunction is well recognized in the field of psychology but remains understudied in the area of voice. Given that the vagus nerve, innervating the larynx, also helps to regulate the ANS, and psychological symptoms commonly observed in patients with FD may reflect ANS dysregulation, research in this area is needed. There is some preliminary evidence that autonomic dysfunction might indeed be associated with FD. However, physiological ANS measures are needed, as well as validated psychological PROMs. What this paper adds to the existing knowledge The first objective of this study is to investigate the occurrence and frequency of symptoms and/or disorders related to autonomic dysfunction in patients with FD as compared with a gender- and age-matched vocally healthy control group. Autonomic (dys)function will be determined by employing both physiological measures (e.g., HRV, skin conductance level) and psychological PROMs (e.g., Neuroception of Psychological Safety Scale, Depression Anxiety and Stress Scale). The second objective is to compare the effects of a novel therapy for FD based on ANS regulation (HRV biofeedback) versus CVT alone or in combination with ANS therapy. What are the potential or actual clinical implications of this work? Success rates of symptomatic CVT for FD are highly variable. This study is expected to lead to innovative results related to the pathogenesis and psychophysiology of FD, a prevalent voice disorder associated with a significant adverse quality of life impact and a substantial financial burden on the healthcare system and society. The results of this study will lead to crucial new insights into both the diagnosis and treatment of FD, contributing to evidence-based practice in the field of voice.

Heart Rate Variability Biofeedback as a Treatment for Military PTSD: A Meta-Analysis

INTRODUCTION

Emerging research has provided tentative support for the use of heart rate variability biofeedback (HRVB) as a treatment for several psychological disorders, with meta-analyses providing compelling evidence for HRVB as a promising treatment for anxiety, depression, and PTSD. Given the prevalence of PTSD in military veterans and the comparatively lower benefit and higher attrition rate of traditional psychological treatment for PTSD relative to civilian counterparts, it is important to examine complementary and alternative treatment approaches such as HRVB in this population. Although studies of HRVB for PTSD have been conducted with military veterans, they have involved relatively small sample sizes, limiting interpretation. To address this, the current article presents a comprehensive meta-analysis, consolidating existing literature to more accurately evaluate the efficacy of HRVB in reducing PTSD symptoms within military populations.

MATERIALS AND METHODS

This meta-analysis was conducted according to Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines, and our protocol was registered with PROSPERO to increase review transparency. A literature search of HRVB interventions was conducted using PubMed, PsycINFO, Military Database, PTSDPubs, and EBSCO's Psychological and Behavioral Sciences Collection.

RESULTS

Five studies met eligibility criteria, providing a combined sample size of 95 military services members. For all studies, effect sizes were negative, indicating a reduction in PTSD symptoms. Effect sizes ranged from -1.614 to -0.414, resulting in an overall moderate to large mean effect for HRVB (Hedges's g = -0.557; 95% confidence interval = -0.818 to -0.296; P < .001). Additionally, cumulative attrition was 5.8%, significantly lower than commonly reported rates for evidence-based treatments (16%-36%).

CONCLUSIONS

The present study is the first meta-analysis to examine HRVB as a treatment for military service members with PTSD. Results indicate that HRVB may be a viable treatment approach to reduce PTSD symptomatology. Low attrition rates, ease of accessibility, and favorable participant outlook serve as additional benefits for the use of HRVB.

Propofol anesthesia destabilizes neural dynamics across cortex

Every day, hundreds of thousands of people undergo general anesthesia. One hypothesis is that anesthesia disrupts dynamic stability-the ability of the brain to balance excitability with the need to be stable and controllable. To test this hypothesis, we developed a method for quantifying changes in population-level dynamic stability in complex systems: delayed linear analysis for stability estimation (DeLASE). Propofol was used to transition animals between the awake state and anesthetized unconsciousness. DeLASE was applied to macaque cortex local field potentials (LFPs). We found that neural dynamics were more unstable in unconsciousness compared with the awake state. Cortical trajectories mirrored predictions from destabilized linear systems. We mimicked the effect of propofol in simulated neural networks by increasing inhibitory tone. This in turn destabilized the networks, as observed in the neural data. Our results suggest that anesthesia disrupts dynamical stability that is required for consciousness.

Feasibility of a remote heart rate variability biofeedback intervention for reducing anxiety in cardiac arrest survivors: A pilot trial

Background

Heart rate variability biofeedback (HRVB) is a promising non-pharmacologic approach for reducing anxiety. This intervention's feasibility needs testing in psychologically distressed cardiac patients for whom heart-related anxiety is a core concern. To enhance scalability and convenience, remote delivery of HRVB also needs to be assessed. Accordingly, we evaluated the feasibility of remote HRVB in survivors of cardiac arrest (CA) with elevated CA-related psychological distress.

Methods

The intervention was comprised of daily sessions of diaphragmatic paced breathing and real-time monitoring of cardiac activity guided by a smartphone app and heart rate monitor. This single-arm feasibility trial assessed the percentage of eligible contacted patients who consented and engaged in the study and the self-reported acceptability, feasibility, appropriateness, and usability of the intervention. Exploratory analyses assessed pre-to-post changes in trait anxiety, negative affect, cardiac-related interoceptive fear, and resting-state HRV.

Results

Of 12 eligible CA survivors contacted, 10 enrolled. All 10 patients completed the virtual study visits and the majority (>50 %) of prescribed training sessions. Ninety percent reported good scores for intervention acceptability and feasibility, and 80 % reported good scores for its appropriateness and usability for reducing fear. Trait anxiety decreased significantly pre-to-post intervention. There were no changes in negative affect, interoceptive fear, or resting state HRV.

Conclusion

A remotely delivered HRVB intervention was acceptable, feasible, and useable for cardiac patients with CA-related psychological distress. A phase 2 randomized controlled trial evaluating the efficacy of HRVB on cardiac patients' psychological distress, health behaviors, and autonomic dysfunction may be warranted.

Psychosocial interventions for survivors of rape and sexual assault experienced during adulthood

BACKGROUND

Exposure to rape, sexual assault and sexual abuse has lifelong impacts for mental health and well-being. Prolonged Exposure (PE), Cognitive Processing Therapy (CPT) and Eye Movement Desensitisation and Reprocessing (EMDR) are among the most common interventions offered to survivors to alleviate post-traumatic stress disorder (PTSD) and other psychological impacts. Beyond such trauma-focused cognitive and behavioural approaches, there is a range of low-intensity interventions along with new and emerging non-exposure based approaches (trauma-sensitive yoga, Reconsolidation of Traumatic Memories and Lifespan Integration). This review presents a timely assessment of international evidence on any type of psychosocial intervention offered to individuals who experienced rape, sexual assault or sexual abuse as adults.

OBJECTIVES

To assess the effects of psychosocial interventions on mental health and well-being for survivors of rape, sexual assault or sexual abuse experienced during adulthood.

SEARCH METHODS

In January 2022, we searched CENTRAL, MEDLINE, Embase, 12 other databases and three trials registers. We also checked reference lists of included studies, contacted authors and experts, and ran forward citation searches.

SELECTION CRITERIA

Any study that allocated individuals or clusters of individuals by a random or quasi-random method to a psychosocial intervention that promoted recovery and healing following exposure to rape, sexual assault or sexual abuse in those aged 18 years and above compared with no or minimal intervention, usual care, wait-list, pharmacological only or active comparison(s). We classified psychosocial interventions according to Cochrane Common Mental Disorders Group's psychological therapies list.

DATA COLLECTION AND ANALYSIS

We used the standard methodological procedures expected by Cochrane.

MAIN RESULTS

We included 36 studies (1991 to 2021) with 3992 participants randomly assigned to 60 experimental groups (3014; 76%) and 23 inactive comparator conditions (978, 24%). The experimental groups consisted of: 32 Cognitive Behavioural Therapy (CBT); 10 behavioural interventions; three integrative therapies; three humanist; five other psychologically oriented interventions; and seven other psychosocial interventions. Delivery involved 1 to 20 (median 11) sessions of traditional face-to-face (41) or other individual formats (four); groups (nine); or involved computer-only interaction (six). Most studies were conducted in the USA (n = 26); two were from South Africa; two from the Democratic Republic of the Congo; with single studies from Australia, Canada, the Netherlands, Spain, Sweden and the UK. Five studies did not disclose a funding source, and all disclosed sources were public funding. Participants were invited from a range of settings: from the community, through the media, from universities and in places where people might seek help for their mental health (e.g. war veterans), in the aftermath of sexual trauma (sexual assault centres and emergency departments) or for problems that accompany the experience of sexual violence (e.g. sexual health/primary care clinics). Participants randomised were 99% women (3965 participants) with just 27 men. Half were Black, African or African-American (1889 participants); 40% White/Caucasian (1530 participants); and 10% represented a range of other ethnic backgrounds (396 participants). The weighted mean age was 35.9 years (standard deviation (SD) 9.6). Eighty-two per cent had experienced rape or sexual assault in adulthood (3260/3992). Twenty-two studies (61%) required fulfilling a measured PTSD diagnostic threshold for inclusion; however, 94% of participants (2239/2370) were reported as having clinically relevant PTSD symptoms at entry. The comparison of psychosocial interventions with inactive controls detected that there may be a beneficial effect at post-treatment favouring psychosocial interventions in reducing PTSD (standardised mean difference (SMD) -0.83, 95% confidence interval (CI) -1.22 to -0.44; 16 studies, 1130 participants; low-certainty evidence; large effect size based on Cohen's D); and depression (SMD -0.82, 95% CI -1.17 to -0.48; 12 studies, 901 participants; low-certainty evidence; large effect size). Psychosocial interventions, however, may not increase the risk of dropout from treatment compared to controls, with a risk ratio of 0.85 (95% CI 0.51 to 1.44; 5 studies, 242 participants; low-certainty evidence). Seven of the 23 studies (with 801 participants) comparing a psychosocial intervention to an inactive control reported on adverse events, with 21 events indicated. Psychosocial interventions may not increase the risk of adverse events compared to controls, with a risk ratio of 1.92 (95% CI 0.30 to 12.41; 6 studies; 622 participants; very low-certainty evidence). We conducted an assessment of risk of bias using the RoB 2 tool on a total of 49 reported results. A high risk of bias affected 43% of PTSD results; 59% for depression symptoms; 40% for treatment dropout; and one-third for adverse events. The greatest sources of bias were problems with randomisation and missing outcome data. Heterogeneity was also high, ranging from I2 = 30% (adverse events) to I2 = 87% (PTSD).

AUTHORS' CONCLUSIONS

Our review suggests that survivors of rape, sexual violence and sexual abuse during adulthood may experience a large reduction in post-treatment PTSD symptoms and depressive symptoms after experiencing a psychosocial intervention, relative to comparison groups. Psychosocial interventions do not seem to increase dropout from treatment or adverse events/effects compared to controls. However, the number of dropouts and study attrition were generally high, potentially missing harms of exposure to interventions and/or research participation. Also, the differential effects of specific intervention types needs further investigation. We conclude that a range of behavioural and CBT-based interventions may improve the mental health of survivors of rape, sexual assault and sexual abuse in the short term. Therefore, the needs and preferences of individuals must be considered in selecting suitable approaches to therapy and support. The primary outcome in this review focused on the post-treatment period and the question about whether benefits are sustained over time persists. However, attaining such evidence from studies that lack an active comparison may be impractical and even unethical. Thus, we suggest that studies undertake head-to-head comparisons of different intervention types; in particular, of novel, emerging therapies, with one-year plus follow-up periods. Additionally, researchers should focus on the therapeutic benefits and costs for subpopulations such as male survivors and those living with complex PTSD.

Methods for Heart Rate Variability Biofeedback (HRVB): A Systematic Review and Guidelines

Heart Rate Variability Biofeedback (HRVB) has been widely used to improve cardiovascular health and well-being. HRVB is based on breathing at an individual's resonance frequency, which stimulates respiratory sinus arrhythmia (RSA) and the baroreflex. There is, however, no methodological consensus on how to apply HRVB, while details about the protocol used are often not well reported. Thus, the objectives of this systematic review are to describe the different HRVB protocols and detect methodological concerns. PsycINFO, CINALH, Medline and Web of Science were searched between 2000 and April 2021. Data extraction and quality assessment were based on PRISMA guidelines. A total of 143 studies were finally included from any scientific field and any type of sample. Three protocols for HRVB were found: (i) "Optimal RF" (n = 37), each participant breathes at their previously detected RF; (ii) "Individual RF" (n = 48), each participant follows a biofeedback device that shows the optimal breathing rate based on cardiovascular data in real time, and (iii) "Preset-pace RF" (n = 51), all participants breathe at the same rate rate, usually 6 breaths/minute. In addition, we found several methodological differences for applying HRVB in terms of number of weeks, duration of breathing or combination of laboratory and home sessions. Remarkably, almost 2/3 of the studies did not report enough information to replicate the HRVB protocol in terms of breathing duration, inhalation/exhalation ratio, breathing control or body position. Methodological guidelines and a checklist are proposed to enhance the methodological quality of future HRVB studies and increase the information reported.

Seasonal Forest Changes of Color and Temperature: Effects on the Mood and Physiological State of University Students

In this study, we attempted to analyze the effect of color and temperature changes in the forest environment over time on the mood and physiological state of university students. The survey was conducted four times considering forest changes such as new leaf appearance and growth, autumn leaf changes, and fallen leaves. The participants' moods and physiological states were first evaluated in an indoor environment; a second evaluation was conducted after contact with the forest. The color visual information of the forest environment was analyzed through color extraction from photographs taken each survey day. The participants' moods and physiological states were measured using the Korean Profile of Mood States-Brief and a heart rate variability measuring device, respectively. Changes in the forest experience according to the season had an effect on university students' mood states. In particular, the effects of the spring forest experience included the relaxation of tension and the activation of vigor. This result is considered to be influenced by factors such as the season's temperature and the green color, which is predominant in the spring forest. However, no physiological changes were found in the participants according to each season. The results of this study can lead to greater consideration of the role of color in urban forest planning for universities and other public spaces.

Heart and brain traumatic stress biomarker analysis with and without machine learning: A scoping review

The enigma of post-traumatic stress disorder (PTSD) is embedded in a complex array of physiological responses to stressful situations that result in disruptions in arousal and cognitions that characterise the psychological disorder. Deciphering these physiological patterns is complex, which has seen the use of machine learning (ML) grow in popularity. However, it is unclear to what extent ML has been used with physiological data, specifically, the electroencephalogram (EEG) and electrocardiogram (ECG) to further understand the physiological responses associated with PTSD. To better understand the use of EEG and ECG biomarkers, with and without ML, a scoping review was undertaken. A total of 124 papers based on adult samples were identified comprising 19 ML studies involving EEG and ECG. A further 21 studies using EEG data, and 84 studies employing ECG meeting all other criteria but not employing ML were included for comparison. Identified studies indicate classical ML methodologies currently dominate EEG and ECG biomarkers research, with derived biomarkers holding clinically relevant diagnostic implications for PTSD. Discussion of the emerging trends, algorithms used and their success is provided, along with areas for future research.

A Pilot Study of a Three-Session Heart Rate Variability Biofeedback Intervention for Veterans with Posttraumatic Stress Disorder

Many veterans do not complete traditional trauma treatments; others may continue to struggle with posttraumatic stress disorder (PTSD) even after completing a full course of therapy (Blasé et al., in Int J Environ Res Public Health 18(7):Article 3329, https://doi.org/10.3390/ijerph18073329 , 2016). Heart rate variability (HRV) biofeedback (HRVB) is a non-invasive, non-pharmacological, breathing-based cardiorespiratory training technique that can reduce trauma symptoms and improve HRV parameters. Prior studies have demonstrated HRVB is well-tolerated by veterans with PTSD symptoms (Tan et al., in Appl Psychophysiol Biofeedback 36(1):27-35, 10.1007/s10484-010-9141-y, 2011; Schuman and Killian, in Appl Psychophysiol Biofeedback 44(1):9-20, https://doi.org/10.1007/s10484-018-9415-3 , 2019). This randomized wait-list controlled pilot study tested a short mobile app-adapted HRVB intervention in combination with treatment as usual for veterans with military-related PTSD to determine if further investigation was warranted. We assessed veterans' military-related PTSD symptoms, depression symptoms, and HRV time and frequency domain measures at baseline, after three clinical sessions, and one month later. This study combined clinical training and home biofeedback with a smartphone app and sensor to reinforce training and validate adherence. In the intervention group, depression and SDNN significantly improved, and we observed marginally significant improvements for PTSD Cluster B (intrusion) symptoms, whereas no significant improvements were observed in the control group. In addition, the brief protocol was acceptable to veterans with PTSD with over 83% of participants completing the study. However, adherence to home practice was low. Findings suggest brief HRVB interventions can decrease comorbid depression and improve overall autonomic function in veterans with PTSD; however, additional research on home biofeedback is necessary to determine the best strategies to increase adherence and which veterans would benefit from brief HRVB interventions.

Biofeedback Enabled CALM (BeCALM)-the feasibility of biofeedback on procedural anxiety during radiation therapy: study protocol for a pilot randomised controlled trial

INTRODUCTION

Patients undergoing treatment for cancer who require radiation therapy (RT) report anxiety specifically relating to the RT procedure. Procedural anxiety can be detrimental to treatment delivery, causing disruptions to treatment sessions, or treatment avoidance. Acute procedural anxiety is most commonly managed with anxiolytic medication. There is a need for effective, non-pharmacological interventions for patients not suitable for, or who prefer to avoid, anxiolytic medication. The primary objectives of this pilot trial are to evaluate the: (1) feasibility of conducting the Biofeedback Enabled CALM (BeCALM) intervention during RT treatment sessions; (2) acceptability of the BeCALM intervention among patients; and (3) acceptability of the BeCALM intervention among radiation therapists. The secondary objective of this pilot trial is to examine the potential effectiveness of the BeCALM intervention delivered by radiation therapists to reduce procedural anxiety during RT.

METHODS AND ANALYSIS

This is a pilot randomised controlled trial. A researcher will recruit adult patients with cancer (3-month recruitment period) scheduled to undergo RT and meeting eligibility criteria for procedural anxiety at the Calvary Mater Hospital, Newcastle (NSW), Australia. Participants will be randomly assigned to receive treatment as usual or the BeCALM intervention (biofeedback plus brief breathing techniques). The primary outcomes are feasibility (measured by recruitment, retention rates and percentage of treatment sessions in which the intervention was successfully delivered); radiation therapists perceived feasibility and acceptability (survey responses); and patient perceived acceptability (survey responses). Secondary outcome is potential effectiveness of the intervention (as measured by the State Trait Anxiety Inventory-State subscale; the Distress Thermometer; and an analysis of treatment duration).

ETHICS AND DISSEMINATION

The study protocol has received approval from Hunter New England Health Human Research Ethics Committee (2021/ETH11356). The results will be disseminated via peer-reviewed publications, as well as presentation at relevant conferences.

TRIAL REGISTRATION NUMBER

ACTRN12621001742864.

The efficacy of heart rate variability biofeedback in patients with acute ischemic stroke: A protocol for systematic review and meta-analysis

BACKGROUND

Stroke is the most common serious neurological disorder, and in high-income countries, it is the fourth-leading cause of death, long-term disability, and reduced quality of life among adults. Heart rate variability (HRV) can improve autonomic dysfunction, cognitive impairment, and psychological distress in other patient populations, but its effect in patients with acute ischemic stroke is still unclear. We conducted a protocol for systematic review and meta-analysis to evaluate the efficacy of HRV biofeedback in patients with acute ischemic stroke.

METHODS

A computerized literature search will be performed in the following electronic databases from their inceptions to October 2022: PubMed, EMBASE, MEDLINE, Cochrane Central Register of Controlled Clinical Trials, China Knowledge Resource Integrated Database, Wanfang Data Information, and Weipu Database for Chinese Technical Periodicals. The risk of bias in the included articles is assessed according to the Risk of Bias Assessment Tool in Cochrane Handbook of Systematic Reviews. Data are analyzed with the Review Manager Version 5.3 software.

RESULTS

This paper will provide high-quality synthesis to assess the efficacy of HRV biofeedback in patients with acute ischemic stroke.

CONCLUSION

HRV biofeedback may be a promising intervention for improving autonomic function, cognitive impairment, and psychological distress in patients with acute ischemic stroke.

Morning blue light treatment improves sleep complaints, symptom severity, and retention of fear extinction memory in post-traumatic stress disorder

Disrupted sleep is a major feature in numerous clinical disorders and is related to decrements in affective memory processing. The prevalence of sleep disruption in post-traumatic stress disorder (PTSD) is suggested to be a key feature that exacerbates the impaired ability to recall extinction memories during experimental fear conditioning. We hypothesized that an intervention employing blue-wavelength light therapy (BLT) to regulate sleep and stabilize circadian rhythms in patients with PTSD (i.e., via regulated morning exposure) would be associated with PTSD symptom improvement, decreased sleep-related complaints, as well as improved consolidation and retention of extinction memories relative to a fear conditioning/extinction paradigm. Eighty-two individuals with PTSD underwent a well-validated fear conditioning/extinction protocol with subsequent assignment to receive morning BLUE (BLT) or placebo AMBER (ALT) light therapy daily for 30-min over 6-weeks. Participants returned after the intervention for post-treatment extinction recall, comprised of exposure to the previously conditioned stimuli, with the difference in skin conductance response between the "extinguished" and the "never-extinguished" stimuli at follow-up. Participants also viewed previously conditioned stimuli in a novel context during a functional magnetic resonance imaging (fMRI) scan. BLUE light therapy was associated with improvements relative to correlated decreases between PTSD symptoms and sleep-related complaints. Participants receiving BLT also sustained retention of the extinction memory, while those in the placebo amber light treatment group showed impairment, characterized by the restoration of the extinguished fear response after 6-weeks. Participants in the ALT also demonstrated greater reactivity in the left insula when viewing the previously extinguished fear-conditioned stimuli in a novel context. Daily BLUE-wavelength morning light exposure was associated with greater retention of extinction learning in patients with PTSD when compared to ALT, as supported by both autonomic and neurobiological reactivity. We speculate that improved sleep facilitated by a stabilized circadian rhythm, after fear-learning, led to greater consolidation of the fear extinction memory, decreased PTSD symptom presentation, and associated decreases in sleep-related complaints. Prominent exposure treatments for PTSD incorporate principles of fear extinction, and our findings suggest that blue light treatment may facilitate treatment gains by promoting the consolidation of extinction memories via improved sleep.

Nature videos for PTSD: protocol for a mixed-methods feasibility study

Background: Given the prevalence of post-traumatic stress disorder (PTSD), particularly among military personnel, new treatment approaches are needed. One may be virtual relaxation interventions, especially 360-degree nature videos, since studies have demonstrated their relaxation effects for healthy participants. If these relaxation effects can be reproduced in patients with PTSD, they may offer a viable tool to reduce distress and hyperarousal. Objective: This research protocol describes a planned study that will examine the relaxation effects of 360-degree nature videos for patients with PTSD. It will also investigate whether these relaxation effects differ depending on the hardware immersion level (head-mounted display [HMD] vs. PC screen) in comparison to a control condition in which patients only listen to natural sounds and do not view a video. Finally, the effect of each intervention's dose duration (five vs. ten minutes) will be explored. Method: A counterbalanced, randomised, controlled, within-subject experiment will be conducted (sample size N = 36). Only soldiers aged 18 years or older with a primary diagnosis of PTSD will be included. Those with psychosis, substance dependence, a change in psychiatric medication within the last month, suicidal intent, and motion sickness will be excluded. All patients will experience the HMD, PC, and control conditions once for five or ten minutes. Self-reported relaxation measures will be collected before and after, and patients' skin conductance level, heart rate, and heart rate variability will be assessed during each condition. Semi-structured interviews will be conducted to examine the patients' experiences in detail. Conclusions: This feasibility study will provide initial evidence of whether viewing 360-degree nature videos via HMD or PC screen is relaxing for patients with PTSD and whether the effects are greater compared with the control condition. The study will also validate the dose duration and thereby informing a subsequent confirmatory interventional trial. Trial registration: DRKS00020277.

HIGHLIGHTS

This randomised controlled feasibility study will examine whether 360-degree nature videos are a suitable relaxation intervention for military personnel with post-traumatic stress disorder.

EEG Evaluation of Stress Exposure on Healthcare Workers During COVID-19 Emergency: Not Just an Impression

Psychological distress among healthcare professionals, although already a common condition, was exacerbated by the COVID-19 pandemic. This effect has been generally self-reported or assessed through questionnaires. We aimed to identify potential abnormalities in the electrical activity of the brain of healthcare workers, operating in different roles during the pandemic. Cortical activity, cognitive performances, sleep, and burnout were evaluated two times in 20 COVID-19 frontline operators (FLCO, median age 29.5 years) and 20 operators who worked in COVID-19-free units (CFO, median 32 years): immediately after the outbreak of the pandemic (first session) and almost 6 months later (second session). FLCO showed higher theta relative power over the entire scalp (FLCO = 19.4%; CFO = 13.9%; p = 0.04) and lower peak alpha frequency of electrodes F7 (FLCO = 10.4 Hz; CFO = 10.87 Hz; p = 0.017) and F8 (FLCO = 10.47 Hz; CFO = 10.87 Hz; p = 0.017) in the first session. FLCO parietal interhemispheric coherence of theta (FLCO I = 0.607; FLCO II = 0.478; p = 0.025) and alpha (FLCO I = 0.578; FLCO II = 0.478; p = 0.007) rhythms decreased over time. FLCO also showed lower scores in the global cognitive assessment test (FLCO = 22.72 points; CFO = 25.56; p = 0.006) during the first session. The quantitative evaluation of the cortical activity might therefore reveal early signs of changes secondary to stress exposure in healthcare professionals, suggesting the implementation of measures to prevent serious social and professional consequences.

Relationship Between Headache Characteristics and a Remote History of TBI in Veterans: A 10-Year Retrospective Chart Review

BACKGROUND AND OBJECTIVES

The objective of this work was to examine the association between deployment-related traumatic brain injury (TBI) severity, frequency, and other injury characteristics with headache outcomes in veterans evaluated at a Veterans Administration (VA) polytrauma support clinic.

METHODS

We conducted a retrospective chart review of 594 comprehensive TBI evaluations between 2011 and 2021. Diagnostic criteria were based on the Department of Defense/VA Consensus-Based Classification of Closed TBI. Adjusted odds ratios (AORs) and 95% CIs were estimated for headache prevalence (logistic), headache severity (ordinal), and prevalence of migraine-like features (logistic) with multiple regression analysis. Regression models were adjusted for age, sex, race/ethnicity, time since injury, and mental health diagnoses.

RESULTS

TBI severity groups were classified as sub concussive exposure (n = 189) and mild (n = 377), moderate (n = 28), and severe TBI (n = 0). Increased headache severity was reported in veterans with mild TBI (AOR 1.72 [95% CI 1.15, 2.57]) and moderate TBI (AOR 3.89 [1.64, 9.15]) compared to those with subconcussive exposure. A history of multiple mild TBIs was associated with more severe headache (AOR 2.47 [1.34, 4.59]) and migraine-like features (AOR 5.95 [2.55, 13.77]). No differences were observed between blast and nonblast injuries; however, greater headache severity was reported in veterans with both primary and tertiary blast effects (AOR 2.56 [1.47, 4.49]). Alteration of consciousness (AOC) and posttraumatic amnesia (PTA) >30 minutes were associated with more severe headache (AOR 3.37 [1.26, 9.17] and 5.40 [2.21, 13.42], respectively). The length of time between the onset of last TBI and the TBI evaluation was associated with headache severity (AOR 1.09 [1.02, 1.17]) and prevalence of migraine-like features (AOR 1.27 [1.15, 1.40]). Last, helmet use was associated with less severe headache (AOR 0.42 [0.23, 0.75]) and lower odds of migraine-like features (AOR 0.45 [0.21, 0.98]).

DISCUSSION

Our data support the notion of a dose-response relationship between TBI severity and headache outcomes. A history of multiple mild TBIs and longer duration of AOC and PTA are unique risk factors for poor headache outcomes in veterans. Furthermore, this study sheds light on the poor headache outcomes associated with subconcussive exposure. Past TBI characteristics should be considered when developing headache management plans for veterans.

Association between spatial working memory and Re-experiencing symptoms in PTSD

BACKGROUND AND OBJECTIVES

Few studies have evaluated the link between working memory (WM) and post-traumatic stress disorder (PTSD). Further, it is unknown whether this relationship is accounted for by other relevant variables including negative affect, emotional dysregulation, or general non-WM-related cognitive control deficits, which are associated with PTSD. The purpose of this study was to determine the extent to which a computerized WM task could predict PTSD symptomology incrementally beyond the contribution of other relevant variables associated with PTSD.

METHODS

Thirty veterans were eligible to complete emotional symptom questionnaires, a heart-rate variability measure, and computerized tasks (i.e., emotional Stroop and automated complex span tasks). A three-stage hierarchical regression was conducted with the PCL-5 total score and symptom clusters (i.e., re-experiencing, avoidance, hyperarousal, and negative cognition/mood) as the dependent variable.

RESULTS

Results revealed that only the re-experiencing symptom cluster was significantly predicted by executive, verbal, and visuospatial WM tasks, which explained an additional 29.7% of the variance over and above other relevant variables. Most notably, the visuospatial task was the only WM task that significantly explained PCL-5 re-experiencing symptoms.

LIMITATIONS

This study was based on a small sample of veterans with PTSD and causality cannot be determined with this cross-sectional study.

CONCLUSIONS

Overall, the results suggest that deficits in visuospatial WM are significantly associated with PTSD re-experiencing symptoms after controlling for other relevant variables. Further research should evaluate whether an intervention to improve visuospatial WM capacity can be implemented to reduce re-experiencing symptoms.

Heart Rate Variability Features as Predictors of Intermittent Theta-Burst Stimulation Response in Posttraumatic Stress Disorder

BACKGROUND

Posttraumatic stress disorder (PTSD) is associated with autonomic dysfunction as indicated by deficits in the sympathetic and parasympathetic nervous systems. These abnormalities are expressed as elevated heart rate and reduced heart rate variability (HRV), respectively. Intermittent theta-burst stimulation (iTBS), a form of transcranial magnetic stimulation, has demonstrated effectiveness in PTSD. Nevertheless, it remains unclear whether HRV may be an iTBS biomarker for PTSD and whether iTBS impacts autonomic activity.

MATERIALS AND METHODS

Fifty veterans with PTSD participated in a randomized controlled trial, receiving ten daily sessions of sham-controlled iTBS (right dorsolateral prefrontal cortex, 1800 pulses/day, 80% active motor threshold, 9.5 min). With a usable dataset (N = 47), HRV parameters were assessed as predictors of clinical response immediately after stimulation. iTBS effects on autonomic response (mean RR interval, root mean square of successive differences [RMSSD], total power [TP], and low-frequency/high-frequency [LF/HF] ratio) were evaluated using an ultra-short approach.

RESULTS

TP and RMSSD were significant predictors of acute clinical response to iTBS. Individuals with higher TP had better response to iTBS with improved symptoms on the Clinician-Administered PTSD Scale (rs = -0.58, p = 0.004), and higher functionality on the Social and Occupational Function Scale (rs = 0.43, p = 0.04). Similarly, higher RMSSD was associated with superior outcomes (rs = -0.44, p = 0.04). No other significant changes in HRV metrics were observed (p ≥ 0.05).

CONCLUSIONS

Our findings indicate that autonomic activity is a potential low-cost and technically simple predictive biomarker of iTBS response in PTSD. Less autonomic dysfunction was associated with superior clinical improvements with iTBS. Future studies might consider HRV acquisition during iTBS, as well as prospective testing of these findings in patients with elevated hyperarousal.

Heart rate variability biofeedback intero-nociceptive emotion exposure therapy for adverse childhood experiences

Background: Psychiatric patients with adverse childhood experiences (ACE) tend to have dysfunctions in the interoceptive part of their emotional experience. The integration of interoceptive emotional activity in the insular and cingulate cortices is linked to the regulation of sympathovagal balance. This makes heart rate variability (HRV) an ideal measure for providing feedback on emotion regulation in real-time.

Methods: A sample of one hundred (n=100) outpatients was evaluated. Participants underwent eight 30-minutes ACE exposure sessions during which patients were guided to experience bodily sensations related to ACE while their HRV was monitored using a commercial biofeedback device.

Results: Comparing the results of the first to last therapeutic session, a significant decrease in heart rate and an increase in HRV at the onset of the session were observed.

Conclusions: This study suggests a physiological impact of therapeutic interventions on autonomic balance and underlines the interest in HRV biofeedback as clinical practice.

Adhésion et implémentation d’un programme de cohérence cardiaque visant à réduire l’anxiété de patients opérés pour une carcinose péritonéale : étude pilote randomisée

Objectif : Évaluer l’implémentation d’une pratique quotidienne de cohérence cardiaque chez des patients opérés pour une carcinose péritonéale.

Matériel et méthode : Étude pilote monocentrique, ouverte, contrôlée, randomisée non comparative, incluant 20 patients en soins courants vs 40 patients formés à la cohérence cardiaque avec biofeedback et guide respiratoire pour une pratique au domicile enregistrée.

Résultats attendus : Adhésion satisfaisante au programme, pouvant caractériser les éléments favorisant son implémentation avant et après chirurgie et évaluation de son impact sur l’anxiété.

Perspectives : Efficacité à déterminer pour transférer ce soin de support.

The Effects of Heart Rate Variability (HRV) Biofeedback on HRV Reactivity and Recovery During and After Anger Recall Task for Patients with Coronary Artery Disease

Patients with coronary artery disease (CAD) often experience anger events before cardiovascular events. Anger is a psychological risk factor and causes underlying psychophysiological mechanisms to lose balance of the autonomic nervous system (ANS). The heart rate variability (HRV) was the common index for ANS regulation. It has been confirmed that heart rate variability biofeedback (HRV-BF) restored ANS balance in patients with CAD during the resting state. However, the effects of HRV-BF during and after the anger event remain unknown. This study aimed to examine the effects of HRV-BF on ANS reactivity and recovery during the anger recall task in patients with CAD. This study was a randomized control trial with a wait-list control group design, with forty patients in the HRV-BF group (for six sessions) and 44 patients in the control group. All patients received five stages of an anger recall task, including baseline, neutral recall task, neutral recovery, anger recall task, and anger recovery. HRV reactivity in the HRV-BF group at the post-test was lower than that in the control group. HRV recovery at the post-test in the HRV-BF group was higher than that in the control group. The HRV-BF reduced ANS reactivity during anger events and increased ANS recovery after anger events for CAD patients. The possible mechanisms of HRV-BF may increase total HRV, ANS regulation, and baroreflex activation at anger events for patients with CAD, and may be a suitable program for cardiac rehabilitation.

Autonomic nervous system correlates of posttraumatic stress symptoms in youth: Meta-analysis and qualitative review

Physiological dysregulation is a key diagnostic criterion for posttraumatic stress disorder (PTSD). While PTSD is defined by trauma exposure, symptom presentations are varied. Similarly, findings of autonomic nervous system (ANS), including parasympathetic (PNS) and sympathetic nervous system (SNS), function in youth exposed to trauma are mixed (e.g., hyporeactivity and hyperreactivity). The present meta-analysis quantitatively assesses the relation between ANS measures broadly, and PNS- and SNS-specific measures, and posttraumatic stress symptoms (PTSS) in youth (ages 4.98 to 19.55 years) across 38 cross-sectional and longitudinal studies (N = 3488). Findings demonstrate that heightened ANS activity is related to increased PTSS during stress tasks (r = 0.07), while decreased SNS activity at rest corresponded to increased PTSS (r = -0.09). The correlation between PNS measures and PTSS was non-significant. The moderation effect of age on the relation between PNS activity measured during stress tasks and PTSS approached significance, such that younger children showed a stronger negative relation between symptoms and PNS activity compared to older youth. Qualitative review of included studies revealed significant variability across sample and stressor characteristics and study methodology. Findings indicate the importance of autonomic dysregulation in youth with PTSS. Additional considerations for future research are discussed.

Modification in Psychophysiological Stress Parameters of Soldiers after an Integral Operative Training Prior to a Real Mission

(1) Background. Military personel could be defined as “Tactical Athletes”. However, experimental evidence about the effects of new HIIT trainings in comparison with traditional training schedules is lacking. The aim of this study was to experimentally analyze the modifications on psycho-physiological and performance response of soldiers after completing experimental integral operative training. (2) Methods. A total of 43 male subjects of a special unit force of the Spanish armed forces were randomly selected and assigned into the experimental and control groups assessed after training and after deploying in a real operation area. The experimental group underwent an integral operative pre-mission 6-week training (IOT), and the control group, the 6-week traditional training. (3) Results. HIIT-based integral operative training significantly improved combat performance (melee combat score) and the psychophysiological stress response, as measured by heart rate variability indexes. (4) Conclusion. This study provides experimental evidence supporting a new integral operative effective for improved autonomic regulation, reduced perceived stress, melee and close-quarter combat techniques, in addition to aerobic and anaerobic performance and lower body strength in comparison with the traditional training.

Effect of a Biofeedback Intervention on Heart Rate Variability in Individuals With Panic Disorder: A Randomized Controlled Trial

OBJECTIVE

Some individuals with panic disorder (PD) display reduced heart rate variability (HRV), which may result in an increased risk of cardiovascular mortality. Heart rate variability-biofeedback (HRV-BF) training has been shown to improve the modulation of the autonomic activity. Therefore, this randomized controlled trial was conducted to investigate the effect of a 4-week HRV-BF intervention in individuals with PD. HRV-BF training improved the modulation of the autonomic activity. Therefore, with this randomized controlled trial, we aimed to investigate the effect of a 4-week HRV-BF intervention in people with PD.

METHODS

Thirty-six women and 16 men with PD (mean age = 35.85 [15.60] years) were randomly allocated either to HRV-BF with 0.1-Hz breathing as intervention group or to HRV-Sham-BF as active control group. HRV-BF was performed for 4 weeks, whereas HRV was measured both during a short-term resting condition and during a paced breathing condition before and after intervention.

RESULTS

HRV-BF with 0.1-Hz breathing increased HRV and reduced panic symptoms in individuals with PD. HRV-BF with 0.1-Hz breathing demonstrated an increase in the time and frequency domain parameters of HRV during the short-term resting condition (ΔPost-Pre root mean square successive differences: 5.87 [14.03] milliseconds; ΔPost-Pre standard deviation of all NN intervals: 11.63 [17.06] milliseconds; ΔPost-Pre total power: 464.88 [1825.47] milliseconds2; ΔPost-Pre power in low-frequency range 0.04-0.15 Hz: 312.73 [592.71] milliseconds2), a decrease in the heart rate during the paced breathing condition (ΔPost-Pre: -5.87 [9.14] beats/min), and a decrease in the Panic and Agoraphobia Scale (ΔPost-Pre: -3.64 [6.30]). There was no intervention effect in the HRV-Sham-BF group.

CONCLUSIONS

HRV-BF as a noninvasive and nonpharmacological treatment seems to be an important intervention option to improve reduced HRV and decrease panic symptoms in individuals with PD. Future studies are needed to establish whether these effects translate to reductions in the risk of cardiovascular disease in PD.

Associations between Heart Rate Variability and Brain Activity during a Working Memory Task: A Preliminary Electroencephalogram Study on Depression and Anxiety Disorder

Heart rate variability (HRV) has been suggested to reflect executive function and related neural activity. Executive dysfunction has been suggested to play an important role in the pathophysiology of emotional disorders. The purpose of this study was to investigate whether HRV showed a significant correlation with electroencephalogram (EEG) during a working memory performance in patients with depressive or anxiety disorder. A retrospective analysis was conducted with data from 61 patients with depressive disorder (43 women and 18 men) and 59 patients with anxiety disorder (35 women and 24 men). HRV was measured in the resting state, and EEG was recorded in the resting state and during the execution of a working memory task. It was performed in patients with depressive and anxiety disorder, and the paired sample t-test between resting state and task performance, as well as the partial correlation analysis between HRV and EEG, was conducted. Both depressed and anxious patients showed weaker beta relative power during the working memory task compared to the rest period. The resting-state EEG did not correlate with HRV parameters in both groups. In depressed patients, HRV showed a positive correlation with delta power during the task and a negative correlation with beta relative power during the task. In patients with anxiety disorder, HRV showed a significant positive correlation with theta power of the right frontal region during the task. Our results suggest that HRV would be related to executive-function-related neural activity in patients with depressive or anxiety disorder. Future studies with more subjects, including healthy controls, are needed to verify the correlation between HRV and EEG and to come up with a more comprehensive picture of neurobiological changes in emotional disorders.

Autonomic changes as reaction to experimental social stress in an inpatient psychosomatic cohort

OBJECTIVES

Patients with psychosomatic disorders suffer from social isolation that might further lead to destabilization and exacerbation of bodily symptoms via autonomic pathways. We aimed to investigate the influence of controlled social stress (model of social ostracism) on the autonomic nerve system (ANS) in an inpatient cohort with psychosomatic disorders.

METHODS

We examined heart rate variability (HRV), skin conductance (SC) and skin temperature (ST) as well as ECG-derived respiration rate (EDR) and subjective reports on stress during exposure to experimental social stress (cyberball game). Data were collected from 123 participants (f:m = 88:35, 42.01 ± 13.54 years) on admission and upon discharge from the university psychosomatic clinic. All data were recorded during baseline, inclusion and exclusion phases of the cyberball game as well as during the recovery phase.

RESULTS

We found significant changes between admission and discharge with a decline in parasympathetic-related HRV parameters (SDRR -3.20 ± 1.30 ms, p = 0.026; RMSSD: -3.77 ± 1.28 ms, p = 0.007) as well as a decrease in SC (-0.04 ± 0.17 μS, p = 0.019) and EDR (-0.01 ± 0.01 Hz, p = 0.007), suggesting a drop in sympathetic tonus, with no changes in ST (p = 0.089) and subjective stress levels (p = 0.322). HRV parameters decreased during the cyberball game (SDRR p = 0.026; RMSSD p = 0.002; lnHF p < 0.001). In contrast, both SC (p < 0.001) and EDR (p < 0.001) increased during the game with SC being slightly lower during the exclusion phase. This can point toward a stimulation of sympathetic nervous system during game participation, which was concordant with the rise in subjective stress values (p < 0.001). ST showed a continuous, unspecific rise over time (p < 0.001).

CONCLUSION

Our data demonstrate the decrease of ANS parameters during experimental social stress when data upon discharge were compared to those upon admission. These results are partially contradictory to previous studies that showed a rise in HRV in a psychiatric cohort over the course of (outpatient) treatment. Further research is required to help attributing these differences to effects of treatment or acute states relating to admission to or discharge from a psychosomatic department.

AI-Based Prediction and Prevention of Psychological and Behavioral Changes in Ex-COVID-19 Patients

The COVID-19 pandemic has adverse consequences on human psychology and behavior long after initial recovery from the virus. These COVID-19 health sequelae, if undetected and left untreated, may lead to more enduring mental health problems, and put vulnerable individuals at risk of developing more serious psychopathologies. Therefore, an early distinction of such vulnerable individuals from those who are more resilient is important to undertake timely preventive interventions. The main aim of this article is to present a comprehensive multimodal conceptual approach for addressing these potential psychological and behavioral mental health changes using state-of-the-art tools and means of artificial intelligence (AI). Mental health COVID-19 recovery programs at post-COVID clinics based on AI prediction and prevention strategies may significantly improve the global mental health of ex-COVID-19 patients. Most COVID-19 recovery programs currently involve specialists such as pulmonologists, cardiologists, and neurologists, but there is a lack of psychiatrist care. The focus of this article is on new tools which can enhance the current limited psychiatrist resources and capabilities in coping with the upcoming challenges related to widespread mental health disorders. Patients affected by COVID-19 are more vulnerable to psychological and behavioral changes than non-COVID populations and therefore they deserve careful clinical psychological screening in post-COVID clinics. However, despite significant advances in research, the pace of progress in prevention of psychiatric disorders in these patients is still insufficient. Current approaches for the diagnosis of psychiatric disorders largely rely on clinical rating scales, as well as self-rating questionnaires that are inadequate for comprehensive assessment of ex-COVID-19 patients' susceptibility to mental health deterioration. These limitations can presumably be overcome by applying state-of-the-art AI-based tools in diagnosis, prevention, and treatment of psychiatric disorders in acute phase of disease to prevent more chronic psychiatric consequences.

Is heart rate variability biofeedback useful in children and adolescents? A systematic review

BACKGROUND

Heart rate variability (HRV) is considered as an index of both physical and emotional health, and biofeedback aiming to increase the level of HRV has demonstrated extensive beneficial effects. Although HRV biofeedback is commonly and reliably applied in adults, the use of this technique, alone or in addition to other treatments, in children and adolescents has not been widely explored to date.

METHODS

This systematic review following PRISMA guidelines covers all human studies using HRV biofeedback in children and adolescents. A literature search was conducted in PsycINFO, PubMed and Scopus, and a standardized methodological quality assessment was performed.

RESULTS

Results showed the efficiency of HRV biofeedback sessions with children and adolescents to reduce physical and mental health-related symptoms and enhance well-being.

CONCLUSIONS

These findings underline the therapeutic value of using HRV biofeedback as a complement to more conventional behavioural and cognitive interventions to help children to manage stress and/or pain. Capitalizing on the identified strengths and shortcomings of available results, we propose research avenues as well as evidence-based clinical guidelines for using HRV biofeedback in clinical paediatric settings.

Interoception and alcohol: Mechanisms, networks, and implications

Interoception refers to the perception of the internal state of the body and is increasingly being recognized as an important factor in mental health disorders. Drugs of abuse produce powerful interoceptive states that are upstream of behaviors that drive and influence drug intake, and addiction pathology is impacted by interoceptive processes. The goal of the present review is to discuss interoceptive processes related to alcohol. We will cover physiological responses to alcohol, how interoceptive states can impact drinking, and the recruitment of brain networks as informed by clinical research. We also review the molecular and brain circuitry mechanisms of alcohol interoceptive effects as informed by preclinical studies. Finally, we will discuss emerging treatments with consideration of interoception processes. As our understanding of the role of interoception in drug and alcohol use grows, we suggest that the convergence of information provided by clinical and preclinical studies will be increasingly important. Given the complexity of interoceptive processing and the multitude of brain regions involved, an overarching network-based framework can provide context for how focused manipulations modulate interoceptive processing as a whole. In turn, preclinical studies can systematically determine the roles of individual nodes and their molecular underpinnings in a given network, potentially suggesting new therapeutic targets and directions. As interoceptive processing drives and influences motivation, emotion, and subsequent behavior, consideration of interoception is important for our understanding of processes that drive ongoing drinking and relapse.

Increasing Heart Rate Variability through Progressive Muscle Relaxation and Breathing: A 77-Day Pilot Study with Daily Ambulatory Assessment

The aim of this study was to examine whether it is possible to gradually increase heart rate variability (HRV) in healthy individuals (21 participants, M = 21.24 years, SD = 1.57, range 19 to 26) through regular exercises of average resonance frequency training (RFT; 6 breaths/min; 5 min each day) and progressive muscle relaxation (PMR; three times a week for 20 min). The effects were tested against an active control group using a linear mixed effect model with random slopes (day), random intercepts (participants) and an autoregressive error term. The special feature of this pilot study is that HRV was measured every day in an ambulatory assessment over 77 days, so that graduate long-term effects on HRV can be mapped. The results indicated that the PMR group significantly increased their HRV compared to the active control group. However, no effect was observed for the RFT group. Possible explanations for these results and important recommendations for subsequent studies are provided.

Synergistic Effect of History of Cardiovascular Disease and Mental Distress on Post-Traumatic Stress Disorder after the Great East Japan Earthquake: The Fukushima Health Management Survey

Cardiovascular disease (CVD) and mental distress have been suggested to be associated with post-traumatic stress disorder (PTSD), but the effect of their combination on PTSD is unknown. We reviewed the synergistic effects of the history of CVD and mental distress on the possibility of PTSD among residents in Fukushima after the Great East Japan Earthquake. This cross-sectional study was conducted among 38,392 participants aged 40–74 years in the evacuation area who applied for the Fukushima Health Management Study in Fiscal Year 2011. Relative excess risk due to interaction (RERI), attributable proportion (AP), odds ratio (OR), and 95% confidence interval (CI) were calculated to investigate the combined effect of history of CVD and mental distress on PTSD. We identified 8104 probable cases of PTSD (21.1%). History of CVD, mental distress, and their combination were positively associated with probable PTSD: the multivariable ORs (95% CIs) were 1.44 (1.04, 2.01), 20.08 (18.14, 22.22), and 26.60 (23.07, 30.67), respectively. There was a significant increase in RERI: the corresponding RERI (95% CI) and AP were 6.08 (3.16, 9.00) and 22.9%. Gender-specific analyses showed similar associations. Thus, we found a supra-additive association of history of CVD and mental distress with probable PTSD after the disaster.

Mind-Body and Psychosocial Interventions May Similarly Affect Heart Rate Variability Patterns in Cancer Recovery: Implications for a Mechanism of Symptom Improvement

Background:

Advancements in early detection and treatment of cancer have led to increased survival rates and greater need to identify effective supportive care options for resolving symptoms of survivorship. Many non-pharmacological approaches to symptom management during and after cancer treatment involve emotional self-regulation as a central strategy for improving well-being. Identifying commonalities among these strategies’ mechanisms of action may facilitate understanding of what might be useful for optimizing intervention effects. Heart rate variability (HRV) parameters are indicative of improved autonomic nervous system (ANS) balance and resiliency and reduced emotional distress and are thus identified as a mechanism to discuss as a marker of potential for intervention efficacy and a target for optimization.

Methods:

HRV data from 2 studies, 1 examining a mind-body intervention and 1 examining a psychosocial intervention, are presented as a point of discussion about preliminary associations between the interventions, change in HRV, and emotional distress reduction.

Results:

HRV significantly decreased in sympathetic activity in response to a mind-body intervention (Qigong/Tai Chi), and increased vagal tone in response to a psychosocial (storytelling) intervention. In both, these changes in HRV parameters were associated with improved emotional states.

Conclusion:

Our preliminary data suggest that HRV may serve as an important marker of underlying changes that mediate emotional regulation; this observation deserves further investigation. If identified as a worthy target, focusing on interventions that improve HRV within the context of interventions for cancer patients may be important to key outcomes and clinical practice.

Increased exhalation to inhalation ratio during breathing enhances high-frequency heart rate variability in healthy adults

Heart rate variability (HRV) is a well-established surrogate of cardiac and emotional health that reflects the balance between sympathetic and parasympathetic activity of the autonomic nervous system. We examined the impact of manipulating exhalation to inhalation ratio (E:I) on HRV, without altering the intrinsic breathing rate of healthy individuals. We hypothesized that a longer exhalation relative to inhalation (E:I > 1) would shift HRV metrics in a direction consistent with increased parasympathetic activity. Twenty-eight individuals (16 young [6M, age = 21-28];12 older adults [6M, age = 66-80]) completed a task during which they paced breathing according to their intrinsic respiratory rate, but altered onset of exhalation and inhalation according to 1:1 sound cue (equal exhalation and inhalation duration) or 2:1 cue (exhalation twice as long as inhalation). Paced 1:1 breathing followed these task conditions to examine residual effects. Estimates of actual E:I ratio based on thoracic movement were 1.08(0.16) for 1:1 task and 1.33(0.20) for 2:1 task, which were significantly different from one another. HRV metrics derived from electrocardiogram included root mean square of the successive differences between normal heartbeats (RMSSD) and high-frequency (HF) HRV. Analyses of HRV metrics by block showed that RMSSD and HF-HRV were higher in the 2:1 task condition compared to 1:1. Time series analysis showed that HF-HRV increased after the end of the 2:1 task block and remained elevated for four minutes. These findings suggest that longer duration of exhalation relative to inhalation, without altering breathing rate, acutely increased RMSSD and HF-HRV, consistent with enhancement of cardiac vagal tone.

Heart Rate Variability Biofeedback Improves Emotional and Physical Health and Performance: A Systematic Review and Meta Analysis

We performed a systematic and meta analytic review of heart rate variability biofeedback (HRVB) for various symptoms and human functioning. We analyzed all problems addressed by HRVB and all outcome measures in all studies, whether or not relevant to the studied population, among randomly controlled studies. Targets included various biological and psychological problems and issues with athletic, cognitive, and artistic performance. Our initial review yielded 1868 papers, from which 58 met inclusion criteria. A significant small to moderate effect size was found favoring HRVB, which does not differ from that of other effective treatments. With a small number of studies for each, HRVB has the largest effect sizes for anxiety, depression, anger and athletic/artistic performance and the smallest effect sizes on PTSD, sleep and quality of life. We found no significant differences for number of treatment sessions or weeks between pretest and post-test, whether the outcome measure was targeted to the population, or year of publication. Effect sizes are larger in comparison to inactive than active control conditions although significant for both. HRVB improves symptoms and functioning in many areas, both in the normal and pathological ranges. It appears useful as a complementary treatment. Further research is needed to confirm its efficacy for particular applications.

Heart rate variability biofeedback in chronic disease management: A systematic review

BACKGROUND

Heart rate variability biofeedback (HRVB) is a non-pharmacological intervention used in the management of chronic diseases.

METHOD

A systematic search was performed according to eligibility criteria including adult chronic patients, HRVB as main treatment with or without control conditions, and psychophysiological outcomes as dependent variables.

RESULTS

In total, 29 articles were included. Reported results showed the feasibility of HRVB in chronic patients without adverse effects. Significant positive effects were found in various patient profiles on hypertension and cardiovascular prognosis, inflammatory state, asthma disorders, depression and anxiety, sleep disturbances, cognitive performance and pain, which could be associated with improved quality of life. Improvements in clinical outcomes co-occurred with improvements in heart rate variability, suggesting possible regulatory effect of HRVB on autonomic function.

CONCLUSIONS

HRVB could be effective in managing patients with chronic diseases. Further investigations are required to confirm these results and recommend the most effective method.

Randomized Sham-Controlled Pilot Study of Neurocardiac Function in Patients With Acute Ischaemic Stroke Undergoing Heart Rate Variability Biofeedback

Background: Neurocardiac dysfunction worsens clinical outcome and increases mortality in stroke survivors. We hypothesized that heart rate variability (HRV) biofeedback improves neurocardiac function by modulating autonomic nervous system activity after acute ischaemic stroke (AIS).

Methods: We randomly allocated (1:1) 48 acute ischaemic stroke patients to receive nine sessions of HRV- or sham biofeedback over 3 days in addition to comprehensive stroke unit care. Before and after the intervention patients were evaluated for HRV via standard deviation of normal-to-normal intervals (SDNN, primary outcome), root mean square of successive differences between normal heartbeats (RMSSD), a predominantly parasympathetic measure, and for sympathetic vasomotor and sudomotor function. Severity of autonomic symptoms was assessed via survey of autonomic symptom scale total impact score (TIS) at baseline and after 3 months.

Results: We included 48 patients with acute ischaemic stroke [19 females, ages 65 (4.4), median (interquartile range)]. Treatment with HRV biofeedback increased HRV post intervention [SDNN: 43.5 (79.0) ms vs. 34.1 (45.0) ms baseline, p = 0.015; RMSSD: 46.0 (140.6) ms vs. 29.1 (52.2) ms baseline, p = 0.015] and alleviated autonomic symptoms after 3 months [TIS 3.5 (8.0) vs. 7.5 (7.0) baseline, p = 0.029], which was not seen after sham biofeedback (SDNN: p = 0.63, RMSSD: p = 0.65, TIS: 0.06). There were no changes in sympathetic vasomotor and sudomotor function (p = ns).

Conclusions: Adding HRV biofeedback to standard stroke unit care led to improved neurocardiac function and sustained alleviation of autonomic symptoms after acute ischaemic stroke, which was likely mediated by a predominantly parasympathetic mechanism.

Clinical Trial Registration:www.ClinicalTrials.gov, identifier: NCT03865225.

Posttraumatic Stress Disorder and Persistent Somatic Symptoms During the COVID-19 Pandemic: The Role of Sense of Threat

OBJECTIVE

Persistent somatic symptoms, such as pain and fatigue, have been referred to as somatization. Somatization is commonly associated with histories of trauma and posttraumatic stress disorder (PTSD). Although previous research has demonstrated that PTSD can predict somatic problems, there has been no examination of this at the level of PTSD symptom clusters and multidimensional assessment of somatic symptoms. We examined the association between the three International Classification of Disease (11th Edition) PTSD symptom clusters (reexperiencing in the here and now, avoidance, and sense of threat), measured in relation to the COVID-19 pandemic as the stressor, and somatic symptoms while statistically adjusting for confounding variables.

METHODS

Participants were a nationally representative sample of 1041 adults from the general population of the Republic of Ireland. Physical health problems across the domains of pain, gastrointestinal, cardiopulmonary, and fatigue were assessed by the Patient Health Questionnaire, and PTSD symptoms were assessed using the International Trauma Questionnaire.

RESULTS

Sense of threat was associated with the presence of pain (β = 0.254), fatigue (β = 0.332), gastrointestinal (β = 0.234), and cardiovascular symptoms (β = 0.239). Avoidance was associated with pain (β = 0.347). Reexperiencing was not associated with any physical health variable.

CONCLUSIONS

In the context of COVID-19, the sense of threat symptoms in PTSD is most strongly related to somatic problems. Findings suggest that interventions addressing sense of threat symptoms might provide relief from somatization.

Use of Mobile Technology Paired with Heart Rate Monitor to Remotely Quantify Behavioral Health Markers among Military Reservists and First Responders

INTRODUCTION

Heart rate variability (HRV) is a biological marker that reflects an individual's autonomic nervous system regulation. Psychological resilience is an individual's ability to recover from an adverse event and return to physiological homeostasis and mental well-being, indicated by higher resting HRV. The Biofeedback Assisted Resilience Training (BART) study evaluates a resilience-building intervention, with or without HRV biofeedback. This article evaluates the feasibility of remote psychophysiological research by validating the HRV data collected.

MATERIALS AND METHODS

The BART platform consists of a mobile health application (BART app) paired to a wearable heart rate monitor. The BART app is installed on the participant's personal phone/tablet to track and collect self-report psychological and physiological data. The platform collects raw heart rate data and processes HRV to server as online biofeedback. The raw data is processed offline to derive HRV for statistical analysis. The following HRV parameters are validated: inter-beat interval, respiratory sinus arrhythmia, low-frequency HRV, biofeedback HRV, and heart period. Bland-Altman and scatter plots are used to compare and contrast online and offline HRV measures. Repeated-measures ANOVA are used to compared means across tasks during the stress (rest, stress, and recovery) and training (rest and paced breathing) sessions in order to validate autonomic nervous system changes to physiological challenges.

RESULTS

The analyses included 245 participants. Bland-Altman plots showed excellent agreement and minimal bias between online and offline unedited inter-beat interval data during the stress session. RMANOVA during the training session indicated a significant strong effect on biofeedback HRV, F(11,390) = 967.96, P < .01. During the stress session, RMANOVA showed significant strong effect on respiratory sinus arrhythmia and low-frequency HRV, and a significant but weak effect on heart period.

CONCLUSIONS

The BART digital health platform supports remote behavioral and physiological data collection, intervention delivery, and online HRV biofeedback.

Posttraumatic Stress Disorder Treatment Effects on Cardiovascular Physiology: A Systematic Review and Agenda for Future Research

Posttraumatic stress disorder (PTSD) is linked to both altered physiological functioning and poorer cardiovascular health outcomes, including an increased risk for cardiovascular disease and cardiovascular-related mortality. An important question is whether interventions for PTSD might ameliorate the risk for poorer health by improving cardiovascular physiological intermediaries. To begin to characterize the literature addressing this question, we conducted a systematic review of empirical studies examining the impact of PTSD interventions on cardiovascular physiological intermediaries, including blood pressure (BP), heart rate (HR), cardiac impedance, and subclinical atherosclerosis. Outcomes included both tonic (i.e., resting) cardiovascular functioning and cardiovascular reactivity (CVR). A total of 44 studies met the inclusion criteria. There was mixed evidence regarding whether PTSD treatment improved tonic cardiovascular functioning. There was stronger evidence that PTSD treatments reduced CVR to trauma-related stressors, particularly for higher-quality studies of cognitive behavioral interventions. No studies examined cardiac impedance or subclinical atherosclerosis. The studies had a high degree of heterogeneity in the populations sampled and interventions tested. Moreover, they generally included small sample sizes and lacked control conditions. Interventions for PTSD may improve cardiovascular physiological outcomes, particularly CVR to trauma cues, although additional methodologically rigorous studies are needed. We outline changes to future research that would improve the literature regarding this important question, including the more frequent use of control groups and larger sample sizes.

Neurophysiological Approach by Self-Control of Your Stress-Related Autonomic Nervous System with Depression, Stress and Anxiety Patients

BACKGROUND

Heart Rate Variability Biofeedback (HRVB) is a treatment in which patients learn self-regulation of a physiological dysregulated vagal nerve function. While the therapeutic approach of HRVB is promising for a variety of disorders, it has not yet been regularly offered in a mental health treatment setting.

AIM

To provide a systematic review about the efficacy of HRV-Biofeedback in treatment of anxiety, depression, and stress related disorders.

METHOD

Systematic review in PubMed and Web of Science in 2020 with terms HRV, biofeedback, Post-Traumatic Stress Disorder (PTSD), depression, panic disorder, and anxiety disorder. Selection, critical appraisal, and description of the Random Controlled Trials (RCT) studies. Combined with recent meta-analyses.

RESULTS

The search resulted in a total of 881 studies. After critical appraisal, nine RCTs have been selected as well as two other relevant studies. The RCTs with control groups treatment as usual, muscle relaxation training and a "placebo"-biofeedback instrument revealed significant clinical efficacy and better results compared with control conditions, mostly significant. In the depression studies average reduction at the Beck Depression Inventory (BDI) scale was 64% (HRVB plus Treatment as Usual (TAU) versus 25% (control group with TAU) and 30% reduction (HRVB) at the PSQ scale versus 7% (control group with TAU). In the PTSD studies average reduction at the BDI-scale was 53% (HRV plus TAU) versus 24% (control group with TAU) and 22% (HRVB) versus 10% (TAU) with the PTSD Checklist (PCL). In other systematic reviews significant effects have been shown for HRV-Biofeedback in treatment of asthma, coronary artery disease, sleeping disorders, postpartum depression and stress and anxiety.

CONCLUSION

This systematic review shows significant improvement of the non-invasive HRVB training in stress related disorders like PTSD, depression, and panic disorder, in particular when combined with cognitive behavioral therapy or different TAU. Effects were visible after four weeks of training, but clinical practice in a longer daily self-treatment of eight weeks is more promising. More research to integrate HRVB in treatment of stress related disorders in psychiatry is warranted, as well as research focused on the neurophysiological mechanisms.

Posttraumatic Stress Disorder Subsequent to Apparent Mild Traumatic Brain Injury

Posttraumatic stress disorder (PTSD) is prevalent among veterans with a history of traumatic brain injury (TBI); however, the relationship between TBI and PTSD is not well understood. We present the case of a 31-year-old male veteran with PTSD who reported TBI before entering the military. The reported injury appeared to be mild: He was struck on the head by a baseball, losing consciousness for ∼10 seconds. Years later, he developed severe PTSD after combat exposure. He was not receiving clinical services for these issues but was encountered in the context of a research study. We conducted cognitive, autonomic, and MRI assessments to assess brain function, structure, and neurophysiology. Next, we compared amygdala volume, uncinate fasciculus diffusion, functional connectivity, facial affect recognition, and baroreceptor coherence with those of a control group of combat veterans (n = 23). Our veteran's MRI revealed a large right medial-orbital prefrontal lesion with surrounding atrophy, which the study neuroradiologist interpreted as likely caused by traumatic injury. Comparison with controls indicated disrupted structural and functional connectivity of prefrontal-limbic structures and impaired emotional, cognitive, and autonomic responses. Detection of this injury before combat would have been unlikely in a clinical context because our veteran had reported a phenomenologically mild injury, and PTSD is a simple explanation for substance abuse, sleep impairment, and psychosocial distress. However, it may be that right prefrontal-limbic disruption imparted vulnerability for the development of PTSD and exacerbated our veteran's emotional response to, and recovery from, PTSD.

Respiratory therapy for the treatment of anxiety: Meta-analytic review and regression

OBJECTIVE

Respiratory abnormalities are a hallmark of anxiety symptomatology and may serve as clinically useful modifiers for alleviating anxiety symptoms. However, gold-standard anxiety treatments (e.g., cognitive-behavioral interventions) often do not directly address respiratory components despite their theoretical utility and clinical accessibility. This review examined the clinical effectiveness of respiratory interventions, interventions that directly target respiration abnormalities and processes, in treating trait anxiety symptoms.

METHODS

The final analysis included 40 randomized controlled trials including at least one measure of trait anxiety, a respiratory-focused intervention group, and a non-respiratory control-group (active or inactive treatment). Overall effects of respiratory focused interventions were examined, as well as the effect of hypothesized moderators.

RESULTS

Respiratory component interventions yielded significantly greater improvements (moderate to large effect) in anxiety symptoms than controls, with the stronger effects observed in comparison to inactive, rather than active, control conditions. Significant heterogeneity in findings suggests that variability in intervention design, population, and control comparison may obfuscate interpretation of findings.

CONCLUSIONS

Evidence supports the clinical utility of respiratory interventions as either an independent anxiety treatment, or as an adjunct to other interventions. Clinical and research implications of findings along with recommendations for ongoing investigations in this domain are discussed.

The Impact of Caring and Killing on Physiological and Psychometric Measures of Stress in Animal Shelter Employees: A Pilot Study

Animal shelter employees are in a unique position where they care for, and later kill, the same animals. The aim of our exploratory study was to assess whether "caring" and/or "killing" evokes physiological and psychometric indicators of stress in employees. Experiment 1 compared three careers that kill regularly, but involve varying degrees of husbandry (n = 28). Blood pressure (BP), salivary cortisol, heart rate (HR), and heart rate variability (HRV) were collected; data showed higher HR and lower HRV during the process of killing. Psychometric scales showed that burnout and Impact Event Scale-Revised (IES-R) scores were higher in careers with higher contact with animals. Experiment 2 compared three careers that involve husbandry, but varying exposure to killing (n = 41). BP, cortisol awakening response, HR, and HRV were measured as well as Professional Quality of Life Scale, IES-R, and Moral Injury Event Scale were administered. There were no significant differences across careers in any measures. The data suggest that the process of killing may be physiologically stressful to the person, and higher levels of animal contact in a euthanasia context may be associated with burnout and traumatic stress, but that the act of euthanasia is not a unique predictor of overall occupational distress.

Measuring Heart Rate Variability in Free-Living Conditions Using Consumer-Grade Photoplethysmography: Validation Study

Background

Heart rate variability (HRV) is used to assess cardiac health and autonomic nervous system capabilities. With the growing popularity of commercially available wearable technologies, the opportunity to unobtrusively measure HRV via photoplethysmography (PPG) is an attractive alternative to electrocardiogram (ECG), which serves as the gold standard. PPG measures blood flow within the vasculature using color intensity. However, PPG does not directly measure HRV; it measures pulse rate variability (PRV). Previous studies comparing consumer-grade PRV with HRV have demonstrated mixed results in short durations of activity under controlled conditions. Further research is required to determine the efficacy of PRV to estimate HRV under free-living conditions.

Objective

This study aims to compare PRV estimates obtained from a consumer-grade PPG sensor with HRV measurements from a portable ECG during unsupervised free-living conditions, including sleep, and examine factors influencing estimation, including measurement conditions and simple editing methods to limit motion artifacts.

Methods

A total of 10 healthy adults were recruited. Data from a Microsoft Band 2 and a Shimmer3 ECG unit were recorded simultaneously using a smartphone. Participants wore the devices for >90 min during typical day-to-day activities and while sleeping. After filtering, ECG data were processed using a combination of discrete wavelet transforms and peak-finding methods to identify R-R intervals. P-P intervals were edited for deletion using methods based on outlier detection and by removing sections affected by motion artifacts. Common HRV metrics were compared, including mean N-N, SD of N-N intervals, percentage of subsequent differences >50 ms (pNN50), root mean square of successive differences, low-frequency power (LF), and high-frequency power. Validity was assessed using root mean square error (RMSE) and Pearson correlation coefficient (R2).

Results

Data sets for 10 days and 9 corresponding nights were acquired. The mean RMSE was 182 ms (SD 48) during the day and 158 ms (SD 67) at night. R2 ranged from 0.00 to 0.66, with 2 of 19 (2 nights) trials considered moderate, 7 of 19 (2 days, 5 nights) fair, and 10 of 19 (8 days, 2 nights) poor. Deleting sections thought to be affected by motion artifacts had a minimal impact on the accuracy of PRV measures. Significant HRV and PRV differences were found for LF during the day and R-R, SDNN, pNN50, and LF at night. For 8 of the 9 matched day and night data sets, R2 values were higher at night (P=.08). P-P intervals were less sensitive to rapid R-R interval changes.

Conclusions

Owing to overall poor concurrent validity and inconsistency among participant data, PRV was found to be a poor surrogate for HRV under free-living conditions. These findings suggest that free-living HRV measurements would benefit from examining alternate sensing methods, such as multiwavelength PPG and wearable ECG.