Autonomic arousal during actigraphically estimated waking and sleep in male veterans with PTSD

Feasibility of a breath robot intervention to reduce sleep problems in posttraumatic stress disorder: protocol for a randomized controlled study

BACKGROUND

Many patients with posttraumatic stress disorder (PTSD) suffer from sleep problems. Robot-based interventions might be an innovative approach to reduce sleep problems and hyperarousal in PTSD. However, the feasibility and effectiveness of a breath robot in patients with PTSD have never been empirically tested. The aim of this study is to investigate the feasibility of a breath robot to reduce sleep problems and hyperarousal in patients with PTSD.

METHODS

This randomized controlled feasibility study will include N = 30 adult patients with at least subsyndromal PTSD (PTSD Symptom Scale - Interview-5 (PSSI-5)) according to the Diagnostic and Statistical Manual of Mental Disorders, 5th Edition (DSM-5) and impaired sleep quality (Pittsburgh Sleep Quality Index (PSQI) > 5). Patients with organic sleep disorders or currently in psychotherapeutic treatment are excluded. Study participants are randomized to receive either a 4-week Somnox 2 robot intervention including simulation of human breath or a 4-week Somnox 2 robot intervention without human breath simulation. The primary outcome will be the proportion of randomized participants providing outcome data at post-treatment. We consider a proportion of > 50% to indicate feasibility. Additional feasibility outcomes include eligibility rate, recruitment speed, uptake, retention, treatment adherence, and dropout. Potential outcomes of effectiveness (sleep quality, PSQI; severity of PTSD symptoms, PSSI-5) will be assessed at two time points, before (T0) and after (T1) the intervention. Sleep characteristics (Consensus Sleep Diary (CSD)) are measured daily.

DISCUSSION

This study is the first to investigate the feasibility of a novel breath robot intervention for reducing sleep problems and hyperarousal in PTSD patients, with effectiveness considered as a secondary outcome. If feasible and effective, the use of a breath robot could be a nonintrusive and flexible intervention to supplement psychotherapy or to bridge treatment gaps.

TRIAL REGISTRATION

DRKS, DRKS00031063. Registered on 10/012023.

Rapid eye movement sleep parasympathetic activity predicts wake hyperarousal symptoms following a traumatic event

Heart rate variability (HRV) can be used to assess changes in output of the parasympathetic nervous system (PNS). Considering that patients with post-traumatic stress disorder (PTSD) often experience disturbances in sleep, arousal, and autonomic functioning, we sought to explore the association of PNS activity during sleep with hyperarousal symptoms of PTSD. Because a broad literature supports the importance of rapid eye movement (REM) sleep in PTSD, REM-sleep features were specifically examined as predictors of PTSD symptom severity. A total of 90 participants, primarily civilian and female, aged 18-40 years who had experienced a traumatic event in the last 2 years, underwent an ambulatory polysomnography (PSG) acclimation night followed by a second PSG night from which sleep physiological measures were computed. Participants underwent an ambulatory polysomnography (PSG) acclimation night followed by a second PSG night from which sleep physiological measures were computed. PTSD severity was measured using the PTSD Checklist for the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (PCL-5). Dependent variables were total PCL-5 score as well as its hyperarousal symptom subscore. Predictors included REM latency, percentage, density, segment length, and an index of parasympathetic tone (root mean square of the successive differences in the R-R interval or RMSSD). Hierarchical regression models were conducted to analyse the association of REM features with PCL-5 total and hyperarousal subscales. Using hierarchical regression, REM-sleep RMSSD accounted for a significant proportion of the variation in outcome variables, even when accounting for other REM-sleep features. The present findings support hypothesised relationships between PTSD symptomatology and REM-sleep physiology and, specifically, that lowered parasympathetic tone in REM may be an important associate of the hyperarousal symptom cluster in PTSD.

Associations between sleep-related heart rate variability and both sleep and symptoms of depression and anxiety: A systematic review

There is a bidirectional relationship between poor sleep and both mood- and anxiety-related disorders, which are among leading global health concerns. Additionally, both disordered sleep and these psychiatric disorders appear to be independently associated with altered autonomic nervous system (ANS) function. We hypothesise that ANS dysregulation during sleep may explain part of the relationship between poor sleep and mood- and anxiety-related disorders. Heart rate variability (HRV) is a frequently used marker of ANS function and gives an indication of ANS input to the heart - in particular, of the relative contributions of sympathetic and parasympathetic activity. A systematic review of PubMed, Scopus and Web of Science yielded 41 studies dealing with sleep, mood- and anxiety-related disorders and sleep-related HRV. Hyperarousal during sleep, reflecting a predominance of sympathetic activation and indicative of ANS dysregulation, may be an important factor in the association between poor sleep and mood-related disorders. Longitudinal studies and mediation analyses are necessary to further understand the potential mediating role of ANS dysregulation on the relationship between poor sleep and mood- and anxiety-related disorders.

Heart rate variability in patients with anxiety disorders: A systematic review and meta-analysis

AIMS

Patients with anxiety disorders (AD) have been found to have lower heart rate variability (HRV) than healthy individuals in some studies, but this was inconsistent. Furthermore, the influence of distinct diagnoses, study design, and demographic factors on the results was not comprehensively examined.

METHODS

We gathered studies comparing HRV in patients with AD and in healthy controls. The parasympathetic activity in the hierarchical order principle was adopted in the main analysis. We adopted the random effects model to calculate the standardized mean difference.

RESULTS

Of the 7805 screened studies, 99 were included in the quantitative analysis, with a total of 4897 AD patients and 5559 controls finally entered the meta-analysis. AD patients had a significantly lower resting-state HRV for parasympathetic activity compared to control (Hedges' g = -0.3897). For the diagnostic subgroup analysis relative to the controls, resting-state HRV was significantly lower in post-traumatic stress disorder, panic disorder, generalized anxiety disorder, and social anxiety disorder patients. HRV reactivity (all reactivity data, data on physiological challenge, and psychological challenge) did not show significant inter-group differences between AD patients and healthy subjects.

CONCLUSIONS

The results supported that patients with AD had significantly lower resting-state HRV than the healthy population, but no alterations were found for HRV reactivity.

Neuronal Circuits Associated with Fear Memory: Potential Therapeutic Targets for Posttraumatic Stress Disorder

Posttraumatic stress disorder (PTSD) is a psychiatric disorder that is associated with long-lasting memories of traumatic experiences. Extinction and discrimination of fear memory have become therapeutic targets for PTSD. Newly developed optogenetics and advanced in vivo imaging techniques have provided unprecedented spatiotemporal tools to characterize the activity, connectivity, and functionality of specific cell types in complicated neuronal circuits. The use of such tools has offered mechanistic insights into the exquisite organization of the circuitry underlying the extinction and discrimination of fear memory. This review focuses on the acquisition of more detailed, comprehensive, and integrated neural circuits to understand how the brain regulates the extinction and discrimination of fear memory. A future challenge is to translate these researches into effective therapeutic treatment for PTSD from the perspective of precise regulation of the neural circuits associated with the extinction and discrimination of fear memories.

Trauma-Related Sleep Problems and Associated Health Outcomes in Police Officers: A Path Analysis

Police officers are frequently exposed to two different types of potentially traumatic events: one dealing with physical threats to self and the other involving the witnessing of harm to others. These different types of traumatic experiences are thought to produce various posttraumatic reactions. Furthermore, sleep problems are also reported as a hallmark of posttraumatic stress disorder. There is evidence, however, that sleep problems may mediate the relationship between posttraumatic stress disorder symptoms and health outcomes, especially physical health and depression. Previous research has shown this to be the case among officers from large urban agencies. The purpose of the present study was to test a model involving a pathway from trauma type and posttraumatic stress disorder symptoms to physical health and depression that is mediated by sleep quality in officers (N = 193) using data from small- to mid-size police agencies. Results revealed that sleep problems served as a mediator between posttraumatic stress disorder hyperarousal and avoidance symptoms and health outcomes, that the trauma types are related to different posttraumatic stress disorder symptoms, and that complicated relationships exist between the study variables. In addition, the results indicated that approximately 25% of our sample displayed probable partial posttraumatic stress disorder or probable full posttraumatic stress disorder, causing substantial functional impairment. Suggestions for improving officer health and performance in the field are provided. Specifically, it appears that interventions designed to address posttraumatic stress disorder hyperarousal symptoms related to personal life threat and the posttraumatic stress disorder avoidance symptoms related to the witnessing of human suffering may maximize officer sleep quality and ultimately overall wellness. In particular, mindfulness-based interventions are well suited for addressing these symptom clusters.

Autonomic dysfunction in posttraumatic stress disorder indexed by heart rate variability: a meta-analysis

BACKGROUND

Changes in autonomic nervous system (ANS) function have been observed in a variety of psychological disorders, including posttraumatic stress disorder (PTSD). Analysis of heart rate variability (HRV) provides insight into the functioning of the ANS. Previous research on PTSD found lower HRV in PTSD patients compared to controls, indicating altered sympathetic and parasympathetic activity, but findings are inconsistent. The purpose of this meta-analysis was to examine differences in HRV indices between individuals with PTSD and healthy controls at baseline and during stress.

METHODS

The included primary studies present an aggregate of studies analyzing different HRV indices. Examined HRV indices were standard deviation of the normalized NN-intervals (SDNN), root mean square of successive differences (RMSSD), low-frequency (LF) and high-frequency (HF) spectral components, LF/HF ratio, and heart rate (HR). Moderating effects of study design, HRV and PTSD assessment, and sample characteristics were examined via subgroup-analyses and meta-regressions.

RESULTS

Random-effects meta-analyses for HRV parameters at rest revealed significant group differences for RMSSD and HF-HRV, suggesting lower parasympathetic activity in PTSD. The aggregated effect size for SDNN was medium, suggesting diminished total variability in PTSD. A small effect was found for LF-HRV. A higher LF/HF ratio was found in the PTSD sample as compared to controls. Individuals with PTSD showed significantly higher HR. During stress, individuals with PTSD showed higher HR and lower HF-HRV, both indicated by small effect sizes.

CONCLUSIONS

Findings suggest that PTSD is associated with ANS dysfunction.

Sleep disturbance in post-traumatic stress disorder (PTSD): a systematic review and meta-analysis of actigraphy studies

BACKGROUND

Sleep disturbance has been described as a 'hallmark' symptom of posttraumatic stress disorder (PTSD). Although there are robust findings of self-reported sleep disturbance in PTSD, evidence of sleep disturbance measured using actigraphy is less certain.

OBJECTIVE

To conduct a systematic review and meta-analysis to determine whether there are any significant differences between individuals with and without PTSD in actigraph-derived sleep measures.

METHOD

Case-control studies comparing participants with current PTSD to those without PTSD were eligible for inclusion. Sleep parameters of interest were: (1) total sleep time; (2) sleep onset latency; (3) wake after sleep onset (WASO); and (4) sleep efficiency. Data were meta-analysed as standardised mean differences (SMDs) and potential sources of heterogeneity were explored through meta-regression. Six actigraphy studies with 405 participants were included.

RESULTS

There was no evidence of a statistically significant difference between those with and without PTSD in total sleep time (SMD 0.09, 95%CI -0.23 to 0.42); WASO (SMD 0.18, 95%CI -0.06 to 0.43); sleep latency (SMD 0.32, 95%CI -0.04 to 0.69); or sleep efficiency (SMD -0.28, 95%CI -0.78 to 0.21).

CONCLUSIONS

Further high-quality research is required to determine whether there is a true difference in sleep between those with and without PTSD.

Randomized clinical trial of capnometry-assisted respiratory training in veterans with posttraumatic stress disorder hyperarousal

OBJECTIVE

To investigate whether capnometry-assisted antihyperventilation respiratory training, successful in treating panic, and sleep hygiene instructions would reduce posttraumatic stress disorder (PTSD) hyperarousal symptoms in U.S. military veterans.

METHOD

We conducted a parallel, nonblinded clinical trial and randomized 80 veterans with PTSD hyperarousal into treatment or wait list. Primary treatment outcomes from baseline to 1st follow-up were analyzed using mixed modeling. Baseline physiological measures were compared between the PTSD hyperarousal group and a no-PTSD group (n = 68).

RESULTS

Baseline respiration rate but not partial-pressure of end-tidal carbon dioxide (PCO₂) was higher in the PTSD hyperarousal group than in the no-PTSD group during 3 min of quiet sitting, indicating no difference in baseline hyperventilation. There was no significant effect of the intervention on PTSD hyperarousal symptoms or hyperventilation compared to wait list, but treatment did lower respiratory rate.

CONCLUSION

This intervention did not reduce PTSD hyperarousal symptoms, perhaps due to differences between underlying mechanisms of PTSD hyperarousal and panic disorder or to differences between veteran and civilian populations. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Posttraumatic stress disorder diagnosis is associated with reduced parasympathetic activity during sleep in US veterans and military service members of the Iraq and Afghanistan wars

Study Objectives

To determine whether high-frequency heart rate variability (HF-HRV) during sleep differs between those with and without posttraumatic stress disorder (PTSD) as a function of sleep type (non-rapid eye movement [NREM] vs. rapid eye movement [REM]), and to explore this relationship across successive sleep cycles. Participants with PTSD were hypothesized to have lower HF-HRV across both REM and NREM sleep.

Methods

Sixty-two post-9/11 military veterans and service members completed self-report measures of sleep quality, insomnia severity, and disruptive nocturnal behaviors. Participants then completed a laboratory-based polysomnographic study night with concurrent HRV assessment.

Results

Participants with PTSD (N = 29) had lower HF-HRV in overall NREM sleep relative to those without PTSD (N = 33) (F(1, 54) = 4.24, p = .04). Groups did not differ on overall HF-HRV during REM sleep. HF-HRV increased over the night for the sample as a whole during both NREM and REM sleep. PTSD status did not moderate the association between HF-HRV and sleep cycles. However, the PTSD group had lower HF-HRV in the first t(155) = 2.67, p = .008, and fourth NREM cycles, t(155) = 2.11, p = .036, relative to participants without PTSD.

Conclusions

Findings suggest blunted parasympathetic modulation during NREM sleep in a young cohort of military veterans and service-members with PTSD. Findings are concerning considering the increased risk of incident cardiovascular events associated with impaired parasympathetic nervous system function. Reduced parasympathetic modulation may be one mechanism underlying the increased prevalence of cardiovascular disease (CVD) among veterans with PTSD.

Assessing sleep quality using self-report and actigraphy in PTSD

Sleep disturbance is commonly reported by participants with post-traumatic stress disorder, but objective evidence of poor sleep is often absent. Here we compared self-report and actigraphic evaluations of sleep between veterans with post-traumatic stress disorder and controls. Participants reported their sleep retrospectively for the month before the recording night and on the recording night. On the recording night, they wore an Actiwatch-64 and were instructed to press the marker button upon getting into bed, each time they awoke, and at their final awakening. The post-traumatic stress disorder group reported much worse sleep than controls on the Pittsburgh Sleep Quality Index for the previous month and somewhat poorer sleep on the recording night. However, on the recording night, neither diary nor actigraphic measures of number of awakenings, total time in bed, nor time lying awake after sleep onset differed between participants with and without post-traumatic stress disorder. Diary-reported number of awakenings was fewer than actigraphically captured awakenings. These results suggest a memory bias towards remembering worse sleep on the nights before the recording night.

Sleep Disturbance in Posttraumatic Stress Disorder: Epiphenomenon or Causal Factor?

PURPOSE OF REVIEW

The goal of this review is to integrate recent findings on sleep disturbance and PTSD, examine sleep disturbance as a causal factor in the development of PTSD, and identify future directions for research, treatment, and prevention.

RECENT FINDINGS

Recent research highlights a relationship between both objective and subjective sleep disturbance and PTSD across diverse samples. Sleep disturbance also predicts PTSD over time. Finally, treatments targeting sleep disturbance lead to decreased PTSD symptoms, while standard PTSD treatments conclude with residual sleep disturbance. Sleep disturbance may be more than a mere epiphenomenon of PTSD. Future research examining the causal role of sleep disturbance in the development of PTSD, as well as the utility of targeting sleep disturbance in prevention and treatment, is necessary to fully understand the likely bidirectional relationship between sleep disturbance and PTSD.

Circadian Contrasts in Heart Rate Variability Associated With Posttraumatic Stress Disorder Symptoms in a Young Adult Cohort

Prior research has demonstrated that individuals exposed to trauma have shown impaired autonomic function. We sought to determine if heart rate variability (HRV), a marker of impaired autonomic function, differed across periods of wake, rest, and sleep as a function of the level of symptoms of posttraumatic stress disorder (PTSD). A sample of young adults (N = 209), 95 of whom met full criteria for current PTSD based on the Clinician Administered PTSD Scale (CAPS; Blake et al., 1995), were evaluated for ≈ 24 hr using actigraphy and electrocardiogram. Actigraphy data were categorized as active, rest, or sleep. Multilevel modeling analyses showed that individuals with high PTSD symptom severity had lower high-frequency HRV than individuals with low PTSD symptom severity during periods of sleep, t(1083) = 2.20, p = .028, Cohen's d = 0.12. No differences were found during periods of activity, t(1083) = 1.34, p = .499, d = 0.05, or rest, t(1083) = 1.34, p = .180, d = 0.09. Our findings extended the import of prior studies to suggest that those with elevated PTSD symptoms may have decreased parasympathetic control during sleep. Moreover, relative to periods of wake and rest, sleep may represent a state of increased vulnerability for decreased parasympathetic cardiac control. Individuals with elevated PTSD symptoms may benefit from early screening for detection of cardiovascular disease.

The impact of posttraumatic stress disorder versus resilience on nocturnal autonomic nervous system activity as functions of sleep stage and time of sleep

Posttraumatic stress disorder (PTSD) has been associated with sleep disturbances including alterations in sleep stages and recently, elevated nocturnal autonomic nervous system (ANS) arousal (i.e., dominance of the sympathetic nervous system over the parasympathetic nervous system). Data suggest that sleep contributes to the regulation of ANS activity. In our previous ambulatory heart rate variability (HRV) monitoring study, strong relationships between sleep and nocturnal ANS activity in resilient participants (i.e., individuals who had never had PTSD despite exposure to high-impact trauma) were not seen with PTSD. In this study, we examined the impact of PTSD vs. resilience on ANS activity as a function of sleep stage and time of sleep. Participants (age 18-35) with current PTSD (n=38) and resilience (n=33) completed two overnight polysomnography recordings in a lab setting. The second night electrocardiogram was analyzed for frequency domain HRV parameters and heart rate within rapid-eye-movement (REM) and non-REM (NREM) sleep periods. Results indicated that ANS arousal indexed by HRV was greater during REM compared with NREM sleep and that the REM-NREM difference was greater in the PTSD than in the resilient participants. This effect of PTSD was reduced to non-significance when analyses controlled for REM sleep percentage, which was lower with PTSD. Exploratory analyses revealed that the REM-NREM difference in HRV was correlated with REM sleep percentage in resilient participants, but not with PTSD. In contrast with our data from home settings, the present study did not find increased overall nocturnal ANS arousal with PTSD. Analyses did reveal higher heart rate during initial NREM sleep with more rapid decline over the course of NREM sleep with PTSD compared with resilience. Findings suggest that elevated ANS arousal indexed by heart rate with PTSD is specific to the early part of sleep and possible impairment in regulating ANS activity with PTSD related to REM sleep.

Noradrenergic dysregulation in the pathophysiology of PTSD

A central role for noradrenergic dysregulation in the pathophysiology of post-traumatic stress disorder (PTSD) is increasingly suggested by both clinical and basic neuroscience research. Here, we integrate recent findings from clinical and animal research with the earlier literature. We first review the evidence for net upregulation of the noradrenergic system and its responsivity to stress in individuals with PTSD. Next, we trace the evidence that the α₁ noradrenergic receptor antagonist prazosin decreases many of the symptoms of PTSD from initial clinical observations, to case series, to randomized controlled trials. Finally, we review the basic science work that has begun to explain the mechanism for this efficacy, as well as to explore its possible limitations and areas for further advancement. We suggest a view of the noradrenergic system as a central, modifiable link in a network of interconnected stress-response systems, which also includes the amygdala and its modulation by medial prefrontal cortex. Particular attention is paid to the evidence for bidirectional signaling between noradrenaline and corticotropin-releasing factor (CRF) in coordinating these interconnected systems. The multiple different ways in which the sensitivity and reactivity of the noradrenergic system may be altered in PTSD are highlighted, as is the evidence for possible heterogeneity in the pathophysiology of PTSD between different individuals who appear clinically similar. We conclude by noting the importance moving forward of improved measures of noradrenergic functioning in clinical populations, which will allow better recognition of clinical heterogeneity and further assessment of the functional implications of different aspects of noradrenergic dysregulation.