Heart rate variability in response to affective scenes in posttraumatic stress disorder

Exaggerated Peripheral and Systemic Vasoconstriction During Trauma Recall in Posttraumatic Stress Disorder: A Co-Twin Control Study

BACKGROUND

Individuals with posttraumatic stress disorder (PTSD) face an increased risk of cardiovascular disease, but the mechanisms linking PTSD to cardiovascular disease remain incompletely understood. We used a co-twin control study design to test the hypothesis that individuals with PTSD exhibit augmented peripheral and systemic vasoconstriction during a personalized trauma recall task.

METHODS

In 179 older male twins from the Vietnam Era Twin Registry, lifetime history of PTSD and current (last month) PTSD symptoms were assessed. Participants listened to neutral and personalized trauma scripts while peripheral vascular tone (Peripheral Arterial Tone ratio) and systemic vascular tone (e.g., total vascular conductance) were measured. Linear mixed-effect models were used to assess the within-pair relationship between PTSD and vascular tone indices.

RESULTS

The mean age of participants was 68 years, and 19% had a history of PTSD. For the Peripheral Arterial Tone ratio analysis, 32 twins were discordant for a history of PTSD, and 46 were discordant for current PTSD symptoms. Compared with their brothers without PTSD, during trauma recall, participants with a history of PTSD had greater increases in peripheral (β = -1.01, 95% CI [-1.72, -0.30]) and systemic (total vascular conductance: β = -1.12, 95% CI [-1.97, -0.27]) vasoconstriction after adjusting for cardiovascular risk factors. Associations persisted after adjusting for antidepressant medication use and heart rate and blood pressure during the tasks. Analysis of current PTSD symptom severity showed consistent results.

CONCLUSIONS

PTSD is associated with exaggerated peripheral and systemic vasoconstrictor responses to traumatic stress reminders, which may contribute to elevated risk of cardiovascular disease.

Probing the neurocardiac circuit in trauma and posttraumatic stress

The neurocardiac circuit is integral to physiological regulation of threat and trauma-related responses. However, few direct investigations of brain-behavior associations with replicable physiological markers of PTSD have been conducted. The current study probed the neurocardiac circuit by examining associations among its core regions in the brain (e.g., insula, hypothalamus) and the periphery (heart rate [HR], high frequency heart rate variability [HF-HRV], and blood pressure [BP]). We sought to characterize these associations and to determine whether there were differences by PTSD status. Participants were N = 315 (64.1 % female) trauma-exposed adults enrolled from emergency departments as part of the prospective AURORA study. Participants completed a deep phenotyping session (e.g., fear conditioning, magnetic resonance imaging) two weeks after emergency department admission. Voxelwise analyses revealed several significant interactions between PTSD severity 8-weeks posttrauma and psychophysiological recordings on hypothalamic connectivity to the prefrontal cortex (PFC), insula, superior temporal sulcus, and temporoparietaloccipital junction. Among those with PTSD, diastolic BP was directly correlated with right insula-hypothalamic connectivity, whereas the reverse was found for those without PTSD. PTSD status moderated the association between systolic BP, HR, and HF-HRV and hypothalamic connectivity in the same direction. While preliminary, our findings may suggest that individuals with higher PTSD severity exhibit compensatory neural mechanisms to down-regulate autonomic imbalance. Additional study is warranted to determine how underlying mechanisms (e.g., inflammation) may disrupt the neurocardiac circuit and increase cardiometabolic disease risk in PTSD.

Heart rate variability and psychological health: The key role of trait emotional awareness

Studies have shown that Trait Emotional Awareness (TEA) - the ability to recognize one's emotions - and Heart Rate Variability (HRV) are both negatively associated with psychological disorders. Although these studies imply that TEA is related to HRV and may explain the association between HRV and psychological disorders, there is limited research investigating this implication. Such investigation is essential to illuminate the psychophysiological processes linked to psychological disorders. The present study aims to investigate a) the association between TEA and HRV, b) the association between HRV and psychological disorders, and c) whether TEA explains the association between HRV and psychological disorders. A sample of 41 German students completed self-report questionnaires as indicators of psychological disorders, including the Hospital Anxiety and Depression Scale (HADS; Snaith & Zigmond, 1983) for anxiousness and depressiveness, as well as the somatization scale of the Hopkins Symptom Checklist (HSCL; Derogatis et al., 1976) for physical complaints. HRV was measured at baseline (resting HRV) and during exposure to a fear-provoking movie clip (reactive HRV). As hypothesized, a) TEA showed a positive association with reactive HRV, b) HRV showed negative associations with anxiousness and physical complaints, and c) TEA explained the relationships between reactive HRV and anxiousness, as well as physical complaints. Contrary to our hypothesis, we did not find any association between HRV and depressiveness. We discussed the contribution of TEA to psychophysiological health, limited generalizability of the current study, and direct future research to explore the underlying mechanisms linking TEA to health.

Effect of cognitive processing therapy on markers of cardiovascular risk in posttraumatic stress disorder patients: A randomized clinical trial

OBJECTIVE

Posttraumatic stress disorder (PTSD) is associated with elevated risk of coronary heart disease (CHD); however, the effects of PTSD treatment on CHD biomarkers is unknown. This study examined whether cognitive processing therapy (CPT) improves 24-hourheart rate variability (HRV), a predictor of CHD mortality.

METHODS

Individuals between the ages of 40 and 65 years with PTSD (n = 112) were randomized to receive 12 sessions of CPT or a Waiting List (WL) intervention comprised of 6 weekly telephone checks of emotional status. The primary outcome variable was 24-hour HRV estimated from the standard deviation of all normal R-R intervals (SDNN); secondary outcomes were the root mean square of successive differences between heart beats (RMSSD), low-frequency HRV (LF-HRV) and high-frequency HRV (HF-HRV). Secondary outcomes also included 24-hour urinary catecholamine excretion, plasma C-reactive protein (CRP), and flow-mediated dilation (FMD) of the brachial artery. For outcomes, linear mixed longitudinal models were used to estimate mean differences (Mdiff).

RESULTS

Participants randomized to the CPT group did not show improved SDNN (Mdiff = 9.8; 95%CI, -2.7 to 22.3; p = 0.12), the primary outcome variable, but showed improved RMSSD (Mdiff = 3.8; 95% CI, 0.5 to 7.1; p = 0.02), LF- HRV (Mdiff =0.3; 95% CI, 0.1 to 0.5; p = 0.01), and HF-HRV (Mdiff = 0.3; 95% CI, 0.0 to 0.6; p = 0.03) compared to WL. There were no differences between groups in catecholamine excretion, FMD, or inflammatory markers.

CONCLUSION

Treating PTSD may not only improve quality of life but may also help ameliorate heightened CHD risk characteristics of PTSD.

Nightmares: an independent risk factor for cardiovascular disease?

STUDY OBJECTIVES

Prior work has established associations between post-traumatic stress disorder (PTSD), disrupted sleep, and cardiovascular disease (CVD), but few studies have examined health correlates of nightmares beyond risks conferred by PTSD. This study examined associations between nightmares and CVD in military veterans.

METHODS

Participants were veterans (N = 3468; 77% male) serving since September 11, 2001, aged 38 years (SD = 10.4); approximately 30% were diagnosed with PTSD. Nightmare frequency and severity were assessed using the Davidson Trauma Scale (DTS). Self-reported medical issues were assessed using the National Vietnam Veterans Readjustment Study Self-report Medical Questionnaire. Mental health disorders were established using the Structured Clinical Interview for DSM-IV. The sample was stratified by the presence or absence of PTSD. Within-group associations between nightmare frequency and severity and self-reported CVD conditions, adjusting for age, sex, race, current smoking, depression, and sleep duration.

RESULTS

Frequent and severe nightmares during the past week were endorsed by 32% and 35% of participants, respectively. Those endorsing nightmares that were frequent, severe, and the combination thereof were more likely to also evidence high blood pressure (ORs 1.42, OR 1.56, and OR 1.47, respectively) and heart problems (OR 1.43, OR 1.48, and OR 1.59, respectively) after adjusting for PTSD diagnosis and other covariates.

CONCLUSIONS

Nightmare frequency and severity among veterans are associated with cardiovascular conditions, even after controlling for PTSD diagnosis. Study findings suggest that nightmares may be an independent risk factor for CVD. Additional research is needed to validate these findings using confirmed diagnoses and explore potential mechanisms.

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.

The impact of traumatic childhood experiences on interoception: disregarding one's own body

BACKGROUND

Deficient interoception, the processing and perception of internal bodily signals, has been discussed as a mechanism underlying various mental disorders. First results indicate a mediating role of interoception in the interplay of traumatic childhood experiences and adult mental disorders. Traumatic childhood experiences may hinder the adequate processing, integration, and trust in bodily signals that are important in order to understand and regulate own needs and emotions, thereby increasing the vulnerability for mental disorders. However, an overarching study investigating alterations in different interoceptive measures and trauma-related disorders as well as their mediating role between early trauma and emotion dysregulation is still missing.

METHODS

One hundred thirty-six individuals with varying levels of traumatic childhood experiences who either had a current diagnosis of major depression, posttraumatic stress disorder, or somatic symptom disorder, or no mental disorder, took part in a multidimensional assessment of interoceptive processes, including interoceptive accuracy, sensibility, and awareness. Kruskal-Wallis tests were used to compare groups regarding interoceptive processes and associations with traumatic childhood experiences and emotion dysregulation were analyzed with Spearman correlations. Furthermore, mediation analyses were computed to examine and compare interoceptive processes as potential mediators between traumatic childhood experiences and emotion dysregulation.

RESULTS

Only body dissociation, a measure for interoceptive sensibility, was significantly reduced in individuals with a current mental disorder. Body dissociation was also the only interoceptive measure significantly associated with traumatic childhood experiences and emotion dysregulation and the only significant mediator in the relationship between traumatic childhood experiences and emotion dysregulation across groups.

CONCLUSION

Results suggest body dissociation, but not other interoceptive measures, as an important feature linking traumatic childhood experiences to current emotion dysregulation, an important transdiagnostic feature. As body dissociation refers to a habitual non-attendance or disregard of interoceptive signals, integrative therapeutic interventions could help affected individuals to overcome difficulties in emotion perception and regulation.

TRIAL REGISTRATION

The general study design was preregistered; see the German Clinical Trials Register (DRKS-ID: DRKS00015182). This study's analysis plan was not preregistered.

PTSD and depression severity are associated with cardiovascular disease symptoms in trauma-exposed women

Background: Posttraumatic stress disorder (PTSD) and depression are associated with increased risk for cardiovascular disease (CVD), which is the leading cause of death and disability worldwide. Epidemiological studies have revealed these illnesses to be highly comorbid, particularly among women. In the current study, we explored associations between indices of cardiovascular health, PTSD, and depression among a sample of trauma-exposed individuals assigned female at birth.Methods: Participants were N = 49 individuals without CVD who reported lifetime Criterion A trauma exposure. Blood pressure (BP), heart rate (HR), and high-frequency heart rate variability (HF-HRV) were collected during a 5-minute resting period. Symptoms of CVD (e.g. extremity pain and swelling, shortness of breath), PTSD, and depression were assessed, along with an exploratory measure of anhedonia.Results: Trauma exposure was positively correlated with systolic BP (r = .32, p = .029) and diastolic BP (r = .30, p = .040). The number of reported CVD symptoms was positively correlated with symptoms of PTSD (r = .41, p = .004), depression (r = .40, p = .005) and anhedonia (r = .38, p = .007). CVD symptoms were also significantly associated with PTSD (β = .41, t = 2.43, p = .023), depression (β = .40, t = 2.76, p = .009), and anhedonia (β = .38, t = 2.51, p = .017) after controlling for age and trauma exposure. These associations were not moderated by HF-HRV in our sample.Conclusions: Our results support the association between PTSD and depressive symptoms and worse cardiovascular functioning among an often-overlooked population that is particularly vulnerable to these illnesses. Future studies should investigate residual impacts of PTSD and depression treatment on CVD risk among trauma-exposed individuals, particularly women.

Vagal control moderates the association between endothelial function and PTSD symptoms in women with T2DM

Background

Individuals with posttraumatic stress disorder (PTSD) are more likely to present with metabolic diseases such as type-2 diabetes mellitus (T2DM), and cardiovascular dysfunction has been implicated in this link. These diseases disproportionately affect women and individuals exposed to chronic environmental stressors (e.g., community violence, poverty). We examined associations among PTSD, cardiovascular indices, and metabolic function in highly trauma-exposed Black women with T2DM.

Methods

Participants (N = 80) were recruited for a follow-up study of stress and T2DM as part of the Grady Trauma Project. PTSD symptoms were assessed with the Clinician Administered PTSD Scale (CAPS-IV). Cardiovascular indices included heart rate (HR), blood pressure (BP), respiratory sinus arrhythmia (RSA), and endothelial function (assessed via flow-mediated dilation; FMD). An oral glucose tolerance test was used as an indicator of metabolic function.

Results

Of the cardiovascular indices, only FMD was significantly associated with PTSD symptoms (CAPS Avoidance symptoms; β = -0.37, p = .042), and glucose tolerance (β = -0.44, p = .019), controlling for age and body mass index. The association between FMD and PTSD Avoidance was moderated by RSA such that the effect of FMD was only significant at low levels of RSA (simple slopes β = -0.87, p = .004).

Conclusions

Our results indicate that endothelial function is significantly related to PTSD and glucose tolerance, over and above other cardiovascular measures (HR, BP, RSA). Further, our results suggest that low RSA may be a risk factor for the link between poor endothelial function and PTSD in women with T2DM.

Association between Heart Rate Variability Indices and Depressed Mood in Patients with Panic Disorder

Objective

Heart rate variability (HRV) reflects the regulation of the autonomic nervous system. Panic disorder is highly associated with autonomic dysfunction, and is often accompanied by depression. The aim of this study is to determine the association between depression and HRV indices in patients with panic disorder.

Methods

A total of 110 outpatients diagnosed with panic disorder participated in this study. The medical records of patients with panic disorder who visited the outpatient clinic of Konkuk University Hospital between December 2018 and March 2020 were retrospectively reviewed. Measurements used in this study include the Panic Disorder Severity Scale-Self Report, Beck Depression Inventory (BDI-II), Insomnia Severity Index, and HRV. Patients were divided into depressive and non-depressive groups based on their BDI-II scores. The association between HRV indices and depressive symptoms was statistically analyzed.

Results

The low frequency/high frequency (LF/HF) ratio was reduced in patients with depression (mean = -0.095, p = 0.004 in the above moderate depressive group, mean = -0.120, p = 0.020 in the severe depressive group). Significant correlations were found between depressive symptoms and standard deviation of NN interval (SDNN) (ms) (-0.19, p = 0.044), very low frequency (VLF) (ms2/Hz) (-0.22, p = 0.021), LF (-0.25, p = 0.008), HF (-0.19, p = 0.043), and LF/HF (-0.25, p = 0.009). Multiple linear regression analysis showed that BDI predicted SDNN (ms), VLF (ms2/Hz), LF, HF, and LF/HF.

Conclusion

We confirmed that the LF/HF ratio decreases when depression is accompanied by panic disorder. HRV indices may be useful markers for detecting depressive symptoms in patients with panic disorder.

Measuring heart rate variability using a heart rate monitor in horses (Equus caballus) during groundwork

Measuring physiological parameters of stress in horses during groundwork, for example when involved in equine-assisted interventions, is important to gain insight into the stress levels of the horses. Heart rate and heart rate variability can be used as physiological indicators of stress in horses. Heart rate monitors could be easily incorporated into practice, as they are not expensive and easy to use. However, it is questionable whether heart rate monitors present accurate heart rate variability results in exercising horses, similar to electrocardiograms. The aim of this study was to determine the accuracy of heart rate monitors for the assessment of heart rate variability in horses during groundwork exercise. Simultaneous telemetric electrocardiograms (Televet) and heart rate monitor (Polar H10 transmitter and M430 receiver, Hylofit electrodes) recordings were performed on 28 horses (15 mares and 13 geldings). Results indicate that the heart rate monitor accurately determined heart rate and time-domain heart rate variability parameters when compared to electrocardiograms during both baseline and groundwork conditions. As expected, heart rate significantly increased and the heart rate variability significantly decreased during groundwork compared to baseline conditions. This indicates that the heart rate monitor can be used to accurately determine heart rate variability during groundwork.

Involvement of the brain-heart axis in the link between PTSD and cardiovascular disease

Posttraumatic stress disorder (PTSD) has long been associated with a heightened risk of cardiovascular disease (CVD). A number of mechanisms have been implicated to underlie this brain-heart axis relationship, such as altered functioning of the autonomic nervous system and increased systemic inflammation. While neural alterations have repeatedly been observed in PTSD, they are rarely considered in the PTSD-CVD link. The brain-heart axis is a pathway connecting frontal and limbic brain regions to the brainstem and periphery via the autonomic nervous system and it may be a promising model for understanding CVD risk in PTSD given its overlap with PTSD neural deficits. We first provide a summary of the primary mechanisms implicated in the association between PTSD and CVD. We then review the brain-heart axis and its relevance to PTSD, as well as findings from PTSD trials demonstrating that a number of PTSD treatments have effects on areas of the brain-heart axis. Finally, we discuss sex considerations in the PTSD-CVD link. A critical next step in this study is to determine if PTSD treatments that affect the brain-heart axis (e.g., brain stimulation that improves autonomic function) also reduce the risk of CVD.

PTSD symptom clusters and cardiovascular responses to stress: Reactivity and recovery

OBJECTIVE

Posttraumatic stress disorder (PTSD) symptoms are associated with high blood pressure (BP) and decreased heart rate variability (HRV) at rest and in response to acute stress. Unique contributions of PTSD symptom clusters to cardiovascular responses to stress are rarely investigated. This study tested whether PTSD-related arousal/reactivity drives relationships of higher PTSD symptoms with higher BP and lower HRV during rest, reactivity (stressor-induced change from baseline), and recovery.

METHODS

Using a cross-sectional observational design, we enrolled 84 trauma-exposed community adults (83% female; 68% White; Mage = 35) who endorsed at least one core PTSD symptom. Participants completed a physical exam, self-reports of trauma history and PTSD symptoms, and BP and HRV frequency domain measurements during rest, stressor (mental arithmetic task), and recovery.

RESULTS

Arousal/reactivity was not associated with BP or HRV reactivity but associated with a higher low (LF) to high (HF) frequency (HF) ratio (LF/HF) during recovery reflecting sympathetic predominance. During the stressor, more avoidance and intrusion were associated with increased diastolic blood pressure (DBP) from baseline; more avoidance was associated with parasympathetic predominance (lower LF/HF); and more negative cognitions/mood was associated with decreased systolic blood pressure (SBP), DBP, and LF from baseline. During recovery, more intrusion and negative cognitions/mood were associated with increased SBP from baseline; less negative cognitions/mood was associated with sympathetic predominance (higher LF/HF).

CONCLUSIONS

PTSD symptom clusters demonstrated differential relationships with SBP, DBP, and HRV during reactivity and recovery. Findings may inform targeted PTSD symptom reduction interventions for disrupting links between PTSD and CVD risk.

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.

Contrasting Associations Between Heart Rate Variability and Brainstem-Limbic Connectivity in Posttraumatic Stress Disorder and Its Dissociative Subtype: A Pilot Study

Background

Increasing evidence points toward the need to extend the neurobiological conceptualization of posttraumatic stress disorder (PTSD) to include evolutionarily conserved neurocircuitries centered on the brainstem and the midbrain. The reticular activating system (RAS) helps to shape the arousal state of the brain, acting as a bridge between brain and body. To modulate arousal, the RAS is closely tied to the autonomic nervous system (ANS). Individuals with PTSD often reveal altered arousal patterns, ranging from hyper- to blunted arousal states, as well as altered functional connectivity profiles of key arousal-related brain structures that receive direct projections from the RAS. Accordingly, the present study aims to explore resting state functional connectivity of the RAS and its interaction with the ANS in participants with PTSD and its dissociative subtype.

Methods

Individuals with PTSD (n = 57), its dissociative subtype (PTSD + DS, n = 32) and healthy controls (n = 40) underwent a 6-min resting functional magnetic resonance imaging and pulse data recording. Resting state functional connectivity (rsFC) of a central node of the RAS – the pedunculopontine nuclei (PPN) – was investigated along with its relation to ANS functioning as indexed by heart rate variability (HRV). HRV is a prominent marker indexing the flexibility of an organism to react adaptively to environmental needs, with higher HRV representing greater effective adaptation.

Results

Both PTSD and PTSD + DS demonstrated reduced HRV as compared to controls. HRV measures were then correlated with rsFC of the PPN. Critically, participants with PTSD and participants with PTSD + DS displayed inverse correlations between HRV and rsFC between the PPN and key limbic structures, including the amygdala. Whereas participants with PTSD displayed a positive relationship between HRV and PPN rsFC with the amygdala, participants with PTSD + DS demonstrated a negative relationship between HRV and PPN rsFC with the amygdala.

Conclusion

The present exploratory investigation reveals contrasting patterns of arousal-related circuitry among participants with PTSD and PTSD + DS, providing a neurobiological lens to interpret hyper- and more blunted arousal states in PTSD and PTSD + DS, respectively.

Trauma-related dissociation and the autonomic nervous system: a systematic literature review of psychophysiological correlates of dissociative experiencing in PTSD patients

Background: Neurophysiological models link dissociation (e.g. feeling detached during or after a traumatic event) to hypoarousal. It is currently assumed that the initial passive reaction to a threat may coincide with a blunted autonomic response, which constitutes the dissociative subtype of post-traumatic stress disorder (PTSD). Objective: Within this systematic review we summarize research which evaluates autonomic nervous system activation (e.g. heart rate, blood pressure) and dissociation in PTSD patients to discern the validity of current neurophysiological models of trauma-related hypoarousal. Method: Of 553 screened articles, 28 studies (N = 1300 subjects) investigating the physiological response to stress provocation or trauma-related interventions were included in the final analysis. Results: No clear trend exists across all measured physiological markers in trauma-related dissociation. Extracted results are inconsistent, in part due to high heterogeneity in experimental methodology. Conclusion: The current review is unable to provide robust evidence that peri- and post-traumatic dissociation are associated with hypoarousal, questioning the validity of distinct psychophysiological profiles in PTSD.

Physiological indicators of emotional arousal related to ANS activity in response to associative cards for psychotherapeutic PTSD treatment

SEE FAR CBT is an integrative treatment protocol for PTSD and anxiety disorders which combines CBT, body-mind (somatic experience) and imagery-based (fantastic reality; FR) methods. FR is introduced using associative therapeutic cards (COPE cards) to represent both "a pleasant/safe place" and the re-narrating process of the traumatic story. Although some preliminary evidence exists regarding the impact of COPE cards integration in psychotherapy, further validation is needed as to whether these cards can induce distinct arousal-affective states in the observer. The aim of this study was to examine whether exposure to COPE cards evoke different emotional-psychophysiological states using objective physiological measures reflecting autonomic nervous system responses; hence, to further validate its use as a potentially effective tool within the context of SEE FAR CBT therapeutic process. Ninety-five healthy under-graduate participants were first exposed to high-arousal, negatively-valenced cards and asked to put themselves in a state of emotional/physical arousal. Afterwards, they were exposed to low-arousal, positively-valenced cards and were asked to try to calm and relax to the best of their ability. Heart rate, blood pressure and heart rate variability (HRV) were measured at baseline, at the arousal phase and finally at the relaxation phase. It was found that exposure to arousing negative cards resulted in significant increase in blood pressure and a decrease in HRV, while exposure to relaxing positive cards resulted in significant decrease in blood pressure and an increase in HRV. These findings support the efficacy and utility of associative COPE cards in affecting psychophysiological arousal.

A prospective examination of sex differences in posttraumatic autonomic functioning

BACKGROUND

Cross-sectional studies have found that individuals with posttraumatic stress disorder (PTSD) exhibit deficits in autonomic functioning. While PTSD rates are twice as high in women compared to men, sex differences in autonomic functioning are relatively unknown among trauma-exposed populations. The current study used a prospective design to examine sex differences in posttraumatic autonomic functioning.

METHODS

192 participants were recruited from emergency departments following trauma exposure (Mean age = 35.88, 68.2% female). Skin conductance was measured in the emergency department; fear conditioning was completed two weeks later and included measures of blood pressure (BP), heart rate (HR), and high frequency heart rate variability (HF-HRV). PTSD symptoms were assessed 8 weeks after trauma.

RESULTS

2-week systolic BP was significantly higher in men, while 2-week HR was significantly higher in women, and a sex by PTSD interaction suggested that women who developed PTSD demonstrated the highest HR levels. Two-week HF-HRV was significantly lower in women, and a sex by PTSD interaction suggested that women with PTSD demonstrated the lowest HF-HRV levels. Skin conductance response in the emergency department was associated with 2-week HR and HF-HRV only among women who developed PTSD.

CONCLUSIONS

Our results indicate that there are notable sex differences in autonomic functioning among trauma-exposed individuals. Differences in sympathetic biomarkers (BP and HR) may have implications for cardiovascular disease risk given that sympathetic arousal is a mechanism implicated in this risk among PTSD populations. Future research examining differential pathways between PTSD and cardiovascular risk among men versus women is warranted.

Emotion dysregulation and dissociation contribute to decreased heart rate variability to an acute psychosocial stressor in trauma-exposed Black women

Reduced heart rate variability (HRV) in response to stress is a biomarker of emotion dysregulation (ED) and is related to posttraumatic stress disorder (PTSD), yet less is known about its role with dissociation in trauma-exposed adults. The goals of the current study were to examine unique patterns of associations between ED, dissociation, and PTSD with HRV at 15, 30, and 45 min (T1, T2, T3) following an acute psychosocial stressor task in a sample of 49 trauma-exposed, urban-dwelling Black women. Associations with baseline psychophysiology measures were also examined. ED and dissociation were assessed using self-report; PTSD was determined using a semi-structured interview. Heart rate (HR) and HRV, indexed with low frequency/high frequency (LF/HF) ratio and respiratory sinus arrhythmia (RSA), were measured with electrocardiogram recordings. ED and dissociation were positively correlated with LF/HF ratio at T3 (p < .05). There were no significant differences between individuals with PTSD versus those without PTSD in HR or HRV following acute stressor; PTSD diagnosis was related to higher HR at baseline. Latent growth modeling revealed that ED was associated with higher LF/HF ratio directly following acute stressor, while dissociation was associated with increase in LF/HF ratio over time. These findings demonstrate that ED is related to higher sympathetic reactivity for a prolonged period of time following stress exposure, while dissociation shows a delayed association with LF/HF ratio, suggesting a distinct impaired parasympathetic activation pattern exists for dissociation.

Using artificial intelligence and longitudinal location data to differentiate persons who develop posttraumatic stress disorder following childhood trauma

Post-traumatic stress disorder (PTSD) is characterized by complex, heterogeneous symptomology, thus detection outside traditional clinical contexts is difficult. Fortunately, advances in mobile technology, passive sensing, and analytics offer promising avenues for research and development. The present study examined the ability to utilize Global Positioning System (GPS) data, derived passively from a smartphone across seven days, to detect PTSD diagnostic status among a cohort (N = 185) of high-risk, previously traumatized women. Using daily time spent away and maximum distance traveled from home as a basis for model feature engineering, the results suggested that diagnostic group status can be predicted out-of-fold with high performance (AUC = 0.816, balanced sensitivity = 0.743, balanced specificity = 0.8, balanced accuracy = 0.771). Results further implicate the potential utility of GPS information as a digital biomarker of the PTSD behavioral repertoire. Future PTSD research will benefit from application of GPS data within larger, more diverse populations.

Post-traumatic stress disorder and its association with stroke and stroke risk factors: A literature review

Stroke is a major cause of mortality and disability globally that has multiple risk factors. A risk factor that has recently gained more attention is post-traumatic stress disorder (PTSD). Literature searches were carried out for updated PTSD information and for the relationship between PTSD and stroke. The review was divided into two sections, one exploring PTSD as an independent risk factor for stroke, with a second concentrating on PTSD's influence on stroke risk factors. The study presents accumulating evidence that shows traumatic stress predicts stroke and is also linked to many major stroke risk factors. The review contributes knowledge to stroke aetiology and acts as a reference for understanding the relationship between PTSD and stroke. The information presented indicates that screening and identification of traumatic experience would be beneficial for directing stroke patients to appropriate psychological and lifestyle interventions. In doing so, the burden of stroke may be reduced worldwide.

Impact of Water Temperature on Heart Rate Variability during Bathing

Background: Heart rate variability (HRV) is affected by many factors. This paper aims to explore the impact of water temperature (WT) on HRV during bathing. Methods: The bathtub WT was preset at three conditions: i.e., low WT (36–38 °C), medium WT (38–40 °C), and high WT (40–42 °C), respectively. Ten subjects participated in the data collection. Each subject collected five electrocardiogram (ECG) recordings at each preset bathtub WT condition. Each recording was 18 min long with a sampling rate of 200 Hz. In total, 150 ECG recordings and 150 WT recordings were collected. Twenty HRV features were calculated using 1-min ECG segments each time. The k-means clustering analysis method was used to analyze the rough trends based on the preset WT. Analyses of the significant differences were performed using the multivariate analysis of variance of t-tests, and the mean and standard deviation (SD) of each HRV feature based on the WT were calculated. Results: The statistics show that with increasing WT, 11 HRV features are significantly (p < 0.05) and monotonously reduced, four HRV features are significantly (p < 0.05) and monotonously rising, two HRV features are rising first and then reduced, two HRV features (fuzzy and approximate entropy) are almost unchanged, and vLF power is rising. Conclusion: The WT has an important impact on HRV during bathing. The findings in the present work reveal an important physiological factor that affects the dynamic changes of HRV and contribute to better quantitative analyses of HRV in future research works.

Respiratory sinus arrhythmia reactivity in anxiety and posttraumatic stress disorder: A review of literature

Respiratory sinus arrhythmia (RSA) reactivity is thought to indicate how adaptively one responds to stress. RSA reactivity has been examined across anxiety disorders and posttraumatic stress disorder (PTSD), to better understand the psychophysiological stress response of these disorders. The current state of the literature is mixed, and the association between RSA reactivity and PTSD/anxiety is unclear. This review examines RSA reactivity in response to laboratory stressor tasks across samples with anxiety and PTSD. Results indicated a complex literature that may suggest an association between anxiety/PTSD and RSA reactivity. There is evidence to suggest a pattern of heightened RSA withdrawal in PTSD and trait anxious samples. There was little evidence to suggest a heightened RSA withdrawal pattern in other anxiety disorders. This review also highlights methodological considerations which may allow for clearer interpretations of RSA reactivity. The current literature includes heterogeneity across stressor tasks, RSA measures, and comorbidities that complicates interpretation of results. Studies using samples with comorbid depression produce more consistent evidence of heightened RSA withdrawal in anxiety/PTSD. Future directions for understanding the contribution of these variables (i.e., stressor tasks, RSA measures, comorbid depression) and mechanisms contributing to the possible association between RSA reactivity and anxiety/PTSD are considered.

Maternal expressions of positive emotion for children predicts children's respiratory sinus arrhythmia surrounding stress

The aim of this study is to assess whether positive emotional exchanges (i.e., emotion coregulation) within the mother-child dyad play a protective role in children's physiological response to a distressing task. Specifically, we test whether positive emotion coregulation among mothers and their preschool-aged children is associated with children's respiratory sinus arrhythmia (RSA) at baseline, during, and following a frustration task. One hundred Singaporean mother-child dyads (M_childage  = 3.5 years) participated in a standardized "Laughing Task" in which positive emotional constructs were measured. Children also participated in a frustration task while RSA was continuously monitored. Hierarchical linear regressions revealed that greater maternal positive emotional responses to children were associated with child RSA at baseline and in recovery from frustration, but not during frustration. These findings have implications for the important role that positive emotion responsivity from mothers may play in children's developing autonomic response systems, and underscore the need for longitudinal work on this topic.

Biomarkers of Pathological Dissociation: A Systematic Review

Pathological dissociation is a severe, debilitating and transdiagnostic psychiatric symptom. This review identifies biomarkers of pathological dissociation in a transdiagnostic manner to recommend the most promising research and treatment pathways in support of the precision medicine framework. A total of 205 unique studies that met inclusion criteria were included. Studies were divided into four biomarker categories, namely neuroimaging, psychobiological, psychophysiological and genetic biomarkers. The dorsomedial and dorsolateral prefrontal cortex, bilateral superior frontal regions, (anterior) cingulate, posterior association areas and basal ganglia are identified as neurofunctional biomarkers of pathological dissociation and decreased hippocampal, basal ganglia and thalamic volumes as neurostructural biomarkers. Increased oxytocin and prolactin and decreased tumor necrosis factor alpha (TNF-α) are identified as psychobiological markers. Psychophysiological biomarkers, including blood pressure, heart rate and skin conductance, were inconclusive. For the genetic biomarker category studies related to dissociation were limited and no clear directionality of effect was found to warrant identification of a genetic biomarker. Recommendations for future research pathways and possible clinical applicability are provided.

Effects of mindfulness training on posttraumatic stress symptoms from a community-based pilot clinical trial among survivors of intimate partner violence

Objective: Exposure to intimate partner violence (IPV) is a significant public health issue associated with deleterious mental and medical health comorbidities, including posttraumatic stress disorder (PTSD). The hallmark symptoms of posttraumatic stress (PTS), even when not meeting the threshold for a diagnosis of PTSD, appear to be underpinned by poor self-regulation in multiple domains, including emotion, cognitive control, and physiological stress. Mindfulness-based stress reduction (MBSR) holds promise for treating PTS symptoms because evidence suggests it targets these domains. The current study was a pilot randomized clinical trial designed to examine changes in emotion regulation, attentional function, and physiological stress dysregulation among women IPV survivors with elevated PTS symptoms after participation in a group-based, 8-week MBSR program. Method: In total, 29 participants were randomized to receive MBSR (n = 19) or an active control (n = 10). Assessments were conducted at study entry, as well as 8 and 12 weeks later. Results: Between-group differences on primary outcomes were nonsignificant; however, when exploring within groups, statistically significant decreases in PTS symptoms, F(1.37, 16.53) = 5.19, p < .05, and emotion dysregulation, F(1.31, 14.46) = 9.36, p < .01, were observed after MBSR but not after the control intervention. Further, decreases in PTSD and emotion dysregulation were clinically significant for MBSR participants but not control participants. Conclusions: These preliminary data signal that MBSR may improve PTS symptoms and emotion regulation and suggest further study of the effectiveness of PTSD interventions guided by integrative models of MBSR mechanisms and psychophysiological models of stress regulation. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Sex differences in post-traumatic stress disorder risk: autonomic control and inflammation

AIM

Over 7 million U.S. adults and about 20% of the military population have post-traumatic stress disorder (PTSD), a debilitating condition that is independently linked to a significantly greater risk of developing cardiovascular disease (CVD). Women have twice the probability of developing PTSD after experiencing a traumatic event compared to men. Existing literatures have reported higher inflammation and autonomic dysfunction including impaired baroreflex sensitivity, increased sympathetic reactivity and decreased parasympathetic activity in PTSD. However, most of these findings stem from studies conducted predominantly in males.

METHODS

We attempt in this narrative review to summarize the mixed literature available on sex differences in autonomic dysfunction and inflammation in PTSD, at rest and in response to stress in PTSD.

RESULTS

This review reveals that there is a paucity of research exploring autonomic function in females with PTSD. Recent studies have included female participants without probing for sex differences. A small number of studies have been conducted exclusively in women. Available data suggest that sympathetic nervous system output tends to be heightened, while parasympathetic activity and arterial baroreflex sensitivity appear more blunted in females with PTSD. Although few studies have investigated sex differences in inflammation in PTSD, data within females suggest chronic increases in inflammation with PTSD. This autonomic dysregulation and inflammation have also been described in males with PTSD.

CONCLUSION

In sum, given the inherent biological differences in CVD clinical presentation and characteristics between men and women, human and animal studies aiming at elucidating sex differences in the pathophysiology of PTSD are needed.

Neurophysiological responses to safety signals and the role of cardiac vagal control

BACKGROUND

Deficits in safety signal learning are well-established in fear-related disorders (e.g., PTSD, phobias). The current study used a fear conditioning paradigm to test associations among eye blink startle and event-related brain potential (ERP) latency measures of safety signal learning, as well as the role of cardiac vagal control (a measure of top-down inhibition necessary for safety learning).

METHODS

Participants were 49 trauma-exposed women ages 17 to 28 years. Eyeblink startle response and ERP amplitudes/latencies were derived for conditioned stimuli associated (CS+) and not associated (CS-) with an aversive unconditioned stimulus. ERPs included the P100 and late positive potential (LPP), which index early visual processing and sustained emotional encoding, respectively. Cardiac vagal control was assessed with resting heart rate variability (HRV).

RESULTS

P100 and LPP latencies for the CS- (safety signal stimulus) were significantly negatively associated with startle to the CS-, but not the CS + . LPP CS- latencies were significantly negatively associated with PTSD Intrusion scores, and this relationship was moderated by vagal control, such that the effect was only present among those with low HRV.

CONCLUSIONS

ERP-based markers of safety signal learning were associated with startle response to the CS- (but not CS+) and PTSD symptoms, indicating that these markers may have relevance for fear-related disorders. Cardiac vagal control indexed by HRV is a moderating factor in these associations and may be relevant to safety signal learning.

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.

Equine-assisted therapeutic activities and their influence on the heart rate variability: A systematic review

OBJECTIVE

To examine the effect of equine-assisted therapeutic interventions on users' heart rate variability, using this said variability as an objective biological variable related to stress levels.

METHOD

A systematic review has been carried out using the methodology suggested in the PRISMA declaration following systematic searches in academic databases.

RESULTS

432 registers were initially identified; however, in the screening and suitability process, nine papers were included in the review. With one exception, all of them reported that equine-assisted therapeutic activities had a favourable effect on users' heart rate variability as such activities favour a state of relaxation by activating the Parasympathetic Nervous System. The analysis of the quality of the evidence and the confirmation of the bias in the works indicate that these results must be considered with caution.

DISCUSSION

Although these preliminary results are promising, more rigorous clinical trials are necessary to overcome the methodological limitations of the works.

Examining the cardiovascular response to fear extinction in a trauma-exposed sample

BACKGROUND

Trauma and symptoms of posttraumatic stress disorder (PTSD) have repeatedly been linked to impaired cardiovascular functioning. Poor fear extinction is a well-established biomarker of PTSD that may provide insight into mechanisms underlying cardiovascular risk. The current study probed the cardiovascular response to extinction in a sample of trauma-exposed individuals.

METHODS

Participants were 51 trauma-exposed women who underwent a fear conditioning paradigm. Heart rate (HR) during extinction was examined in response to a conditioned stimulus that was previously paired with an aversive unconditioned stimulus (CS+) and one that was never paired (CS-). Heart rate variability (HRV) was calculated at baseline and during the extinction session.

RESULTS

Consistent with fear bradycardia, initial HR deceleration (.5-2s) after CS + onset occurred during early extinction and appeared to extinguish over time. Higher baseline HRV was significantly associated with greater fear bradycardia during early extinction.

CONCLUSIONS

This is the first study to demonstrate a pattern of fear bradycardia in early extinction, which was associated with higher HRV levels and decreased over the course of the extinction phase. These results suggest that increased fear bradycardia may be indicative of greater vagal control (i.e., HRV), both of which are psychophysiological biomarkers that may influence cardiovascular and autonomic disease risk in trauma-exposed individuals.

Nervous and Endocrine System Dysfunction in Posttraumatic Stress Disorder: An Overview and Consideration of Sex as a Biological Variable

Decades of research into the biological mechanisms of posttraumatic stress disorder (PTSD) suggests that chronic activation of the stress response leads to long-lasting changes in the structure and function of the nervous and endocrine systems. While the prevalence of PTSD is twice as high in females as males, little is known about how sex differences in neuroendocrine systems may contribute to PTSD. In response to the paucity of research on sex-related mechanisms, the National Institutes of Health created a policy that asks researchers to consider sex as a biological variable. This review provides an overview of the current understanding of nervous and endocrine dysfunction in PTSD (e.g., neural circuitry, autonomic arousal, hormonal response), highlighting areas where the influence of sex has been characterized and where further research is needed. We also provide recommendations for using the sex-as-a-biological-variable policy to address specific gaps in PTSD neuroscience research.

Post-Traumatic Stress, Mother's Emotion Regulation, and Parenting in Survivors of Intimate Partner Violence

Post-traumatic stress symptoms (PTSS) are high among female survivors of intimate partner violence (IPV), and children of parents experiencing PTSS are at heightened risk for a wide range of emotional and behavioral problems. Parenting has significant influence on child adjustment, and although links have been found between parental psychopathology and maladaptive parenting, little is known about the factors that may explain this relation. The current study examines mother's emotion regulation (ER) as a factor influencing the relation between mother PTSS and parenting around children's emotions in a study sample of sixty-four female survivors of IPV and their 6- to 12-year-old children. Mothers reported on their own PTSS and their parenting. Respiratory sinus arrhythmia (RSA) was used as a psychophysiological index of mother's ER. Experiential components of mother's ER was also measured by observer coding of the Meta-Emotion Interview, a structured assessment that asks parents about their attitudes toward and experiences with emotions, including their regulation of emotions. Mother's RSA reactivity moderated the relation between PTSS and negative parenting. There was also a significant indirect relation between mothers' PTSS symptom severity and supportive parenting reactions through mothers' self-report of ER. Results suggest that mother's ER abilities represent factors that significantly affect associations between maternal PTSS and parent's emotion socialization practices. Implications for assessment and intervention with families exposed to the stress of IPV are discussed.

Posttraumatic Stress Disorder and Alterations in Resting Heart Rate Variability: A Systematic Review and Meta-Analysis

OBJECTIVE

The functions of both the central and peripheral autonomic nervous system, indexed by heart rate variability (HRV), are affected by psychology and physiology. This review summarizes the results of studies comparing the evaluation of HRV parameters between individuals with posttraumatic stress disorder (PTSD) and healthy controls.

METHODS

Eligible studies (n=499) were identified through literature searches of the EMBASE, Medline, PubMed and Web of Science databases. Nineteen studies met our inclusion criteria. A random effects model was used, and standardized mean differences for highfrequency HRV(HF-HRV), low-frequency HRV(LF-HRV) and the root mean square of successive R-R interval differences (RMSSD) were calculated.

RESULTS

Significant effects were found for HF-HRV [p<0.0001, Z=4.18; Hedges'g=-1.58, 95% confidence interval (CI) (-2.32, -0.84); k=14] and RMSSD [p<0.00001, Z=4.80; Hedges'g=-1.96, 95% CI (-2.76, -1.16); k=9] relative to healthy controls. Considerable heterogeneity was revealed, but the main effects for HF-HRV and RMSSD were robust in subsequent meta-regression and subgroup analyses.

CONCLUSION

Given the relationships among low vagal state, inflammation, and alterations in brain structure and function, including executive function and emotion regulation, reduced HRV may be regarded as an endophenotype in PTSD research.

Heart and Brain Interaction of Psychiatric Illness: A Review Focused on Heart Rate Variability, Cognitive Function, and Quantitative Electroencephalography

Heart rate variability (HRV) reflects beat-to-beat variability in the heart rate due to the dynamic interplay of the sympathetic and parasympathetic nervous systems. HRV is considered an index of the functional status of the autonomic nervous system. A decrease in HRV is thus observed in individuals with autonomic dysfunction. Abnormal HRV has been reported in a range of mental disorders. In this review, we give an overview of HRV in patients with major depressive disorder (MDD), schizophrenia, and posttraumatic stress disorder (PTSD), one of whose core symptoms is cognitive dysfunction. The association between HRV and cognitive function is highlighted in this review. This review consists of three main sections. In the first section, we examine how HRV in patients with MDD, schizophrenia, and PTSD is characterized, and how it is different when compared to that in healthy controls. In the second section, beyond the heart itself, we discuss the intimate connection between the heart and the brain, focusing on how HRV interacts with quantitative electroencephalography (qEEG) in the context of physiological changes in the sleep cycle. Lastly, we finish the review with the examination of the association between HRV and cognitive function. The overall findings indicate that the reduction in HRV is one of main manifestations in MDD, schizophrenia, and PTSD, and also more generally HRV is closely linked to the change in qEEG and also to individual differences in cognitive performance.

Examining the Prospective Relationship between Pre-Disaster Respiratory Sinus Arrhythmia and Post-Disaster Posttraumatic Stress Disorder Symptoms in Children

Previous studies have examined the concurrent relationship between posttraumatic stress disorder (PTSD) and a range of psychophysiological variables, including respiratory sinus arrhythmia (RSA). However, there is a lack of research examining the prospective development of trauma symptomatology, and the directionality of the association between RSA level and PTSD has yet to be determined. The current study is the first prospective study to examine whether RSA level and RSA reactivity are risk factors for PTSD symptoms in children. Assessments were conducted both prior to (Time 1) and following (Time 2) a natural disaster (i.e., Hurricane Katrina). Participants were 36 children who were 3-6 years-old during the Time 1 assessment. Structured diagnostic interviews were used to assess PTSD symptoms at both Time 1 and Time 2. RSA level during a neutral stimulus, RSA reactivity to emotional video stimuli (distress, joy, and trauma videos) and RSA reactivity to memory stimuli (remote happy memory, trauma memory, mother's recall of the trauma memory) were also collected at both time points. Time 1 RSA level during a neutral stimulus was a significant predictor of Time 2 PTSD symptoms (controlling for age, Time 1 PTSD symptoms, Time 2 neutral RSA level), such that lower RSA during a neutral condition was related to higher PTSD symptoms. Also, Time 1 RSA reactivity in response to memory (but not video) stimuli, in the form of relatively less vagal withdrawal, was a significant predictor of more Time 2 PTSD symptoms (controlling for age, Time 1 PTSD symptoms, Time 2 RSA reactivity). This unique prospective study provides evidence for level of RSA and RSA reactivity as pre-existing clinical markers of stress sensitivity that predict psychopathology following a trauma.

The long-term effects of early-life trauma on psychological, physical and physiological health among the elderly: the study of Holocaust survivors

Objectives: To study post-traumatic stress symptoms and post-traumatic growth and heart rate variability among elderly Holocaust survivors and a matched comparison group and the mediational effect of post-traumatic stress symptoms and post-traumatic growth on the association between Holocaust experience and heart rate variability. Method: 159 Holocaust survivors and 87 matched participants without Holocaust experience answered post-traumatic stress symptoms and post-traumatic growth questionnaires. Heart rate variability time and frequency parameters were measured for a subsample of N = 133. Results: Holocaust survivors reported higher levels of post-traumatic stress symptoms and post-traumatic growth. Most heart rate variability measures were similar in the two groups, except for better heart rate variability measured by the ratio of low frequency/high frequency among Holocaust survivors. Structural equation modeling showed that belonging to the Holocaust survivor group was associated with higher post-traumatic stress symptoms and higher post-traumatic growth, as well as better heart rate variability scores (standard deviation of normal to normal R-R intervals, high frequency and the ratio of low frequency/high frequency) through the mediation of post-traumatic stress symptoms and post-traumatic growth. Conclusions: The study emphasized the duality of the association between post-traumatic stress symptoms and post-traumatic growth and their integrated effect on heart rate variability.

Biofeedback-Assisted Resilience Training for Traumatic and Operational Stress: Preliminary Analysis of a Self-Delivered Digital Health Methodology

Background

Psychological resilience is critical to minimize the health effects of traumatic events. Trauma may induce a chronic state of hyperarousal, resulting in problems such as anxiety, insomnia, or posttraumatic stress disorder. Mind-body practices, such as relaxation breathing and mindfulness meditation, help to reduce arousal and may reduce the likelihood of such psychological distress. To better understand resilience-building practices, we are conducting the Biofeedback-Assisted Resilience Training (BART) study to evaluate whether the practice of slow, paced breathing with or without heart rate variability biofeedback can be effectively learned via a smartphone app to enhance psychological resilience.

Objective

Our objective was to conduct a limited, interim review of user interactions and study data on use of the BART resilience training app and demonstrate analyses of real-time sensor-streaming data.

Methods

We developed the BART app to provide paced breathing resilience training, with or without heart rate variability biofeedback, via a self-managed 6-week protocol. The app receives streaming data from a Bluetooth-linked heart rate sensor and displays heart rate variability biofeedback to indicate movement between calmer and stressful states. To evaluate the app, a population of military personnel, veterans, and civilian first responders used the app for 6 weeks of resilience training. We analyzed app usage and heart rate variability measures during rest, cognitive stress, and paced breathing. Currently released for the BART research study, the BART app is being used to collect self-reported survey and heart rate sensor data for comparative evaluation of paced breathing relaxation training with and without heart rate variability biofeedback.

Results

To date, we have analyzed the results of 328 participants who began using the BART app for 6 weeks of stress relaxation training via a self-managed protocol. Of these, 207 (63.1%) followed the app-directed procedures and completed the training regimen. Our review of adherence to protocol and app-calculated heart rate variability measures indicated that the BART app acquired high-quality data for evaluating self-managed stress relaxation training programs.

Conclusions

The BART app acquired high-quality data for studying changes in psychophysiological stress according to mind-body activity states, including conditions of rest, cognitive stress, and slow, paced breathing.

Young Children's Physiological Reactivity during Memory Recall: Associations with Posttraumatic Stress and Parent Physiological Synchrony

Autonomic reactivity is implicated in stress response and social engagement - both key components of posttraumatic stress disorder (PTSD) - but few studies have examined autonomic reactivity in pediatric samples, and no known studies have examined physiological synchrony among children with PTSD and caregivers. In a sample of 247 young children (94 girls, 153 boys), most (85%) of whom had exposure to trauma and 40% who met criteria for PTSD, we examined children's patterns of respiratory sinus arrhythmia (RSA) at baseline and in response to a memory recall task, as well as correspondence between parents' and children's RSA. Children with PTSD demonstrated significantly higher reactivity than other groups during their recollection of a traumatic memory, but not during other memory tasks. Regarding synchrony, caregivers' and children's RSA were more significantly and positively correlated during the trauma recall task among children who had had exposure to a potentially traumatic event but did not meet PTSD criteria, suggesting physiological synchrony may be protective in contexts of trauma. Overall, findings demonstrate physiological reactivity differences among young children with PTSD. While more work is needed to understand the meaning of parent-child physiological synchrony, these data suggest that children's psychopathology is associated with physiological synchrony processes among young children with exposure to trauma.

Assessing Anxiety Disorders Using Wearable Devices: Challenges and Future Directions

Wearable devices (WD) are starting to increasingly be used for interventions to promote well-being by reducing anxiety disorders (AD). Electrocardiogram (ECG) signal is one of the most commonly used biosignals for assessing the cardiovascular system as it significantly reflects the activity of the autonomic nervous system during emotional changes. Little is known about the accuracy of using ECG features for detecting ADs. Moreover, during our literature review, a limited number of studies were found that involve ECG collection using WD for promoting mental well-being. Thus, for the sake of validating the reliability of ECG features for detecting anxiety in WD, we screened 1040 articles, and only 22 were considered for our study; specifically 6 on panic, 4 on post-traumatic stress, 4 on generalized anxiety, 3 on social, 3 on mixed, and 2 on obsessive-compulsive anxiety disorder articles. Most experimental studies had controversial results. Upon reviewing each of these papers, it became apparent that the use of ECG features for detecting different types of anxiety is controversial, and the use of ECG-WD is an emerging area of research, with limited evidence suggesting its reliability. Due to the clinical nature of most studies, it is difficult to determine the specific impact of ECG features on detecting ADs, suggesting the need for more robust studies following our proposed recommendations.

Clinical utility of heart rate variability during Head-up tilt test in subjects with chronic posttraumatic stress disorder

Posttraumatic stress disorder (PTSD) is characterized by psychophysiological abnormalities, such as an altered baseline heart rate and hyperarousal, implying dysfunctional arousal regulation. Heart rate variabilities (HRVs) is known to reflect autonomic nervous system activity. We examined the changes of HRVs in PTSD patients with head-up tilt position to closely investigate disease-specific changes in autonomic function in PTSD patients. Sixty-seven patients with PTSD and 72 patients without PTSD were assessed using the PTSD Checklist for DSM-5 (PCL-5) and psychiatric interview. Heart rate data including standard deviation of the NN intervals, the square root of the mean squared differences of successive NN intervals, log low-frequency and log high-frequency were collected for 10 min before and after tilting. Considering interactions between groups and head-up tilting, the head-up tilting induced reduction of the high-frequency component of HRVs was significantly greater in the PTSD group [F (1, 272) = 4.718, p = 0.031]. The change of HRVs in PTSD patients suggested the presence of autonomic dysfunction in despite of the posture.

Vagus nerve stimulation as a tool for enhancing extinction in exposure-based therapies

RATIONALE

Emotionally traumatic experiences can lead to maladaptive memories that are enduring and intrusive. The goal of exposure-based therapies is to extinguish conditioned fears through repeated, unreinforced exposures to reminders of traumatic events. The extinction of conditioned fear depends upon the consolidation of new memories made during exposure to reminders. An impairment in extinction recall, observed in certain patient populations, can interfere with progress in exposure-based therapies, and the drive to avoid thoughts and reminders of the trauma can undermine compliance and increase dropout rate. Effective adjuncts to exposure-based therapies should improve the consolidation and maintenance of the extinction memory or improve the tolerability of the therapy. Under stressful conditions, the vagus nerve responds to elevations in epinephrine and signals the brain to facilitate the storage of new memories while, as part of the parasympathetic nervous system, it slows the sympathetic response.

OBJECTIVE

Here, we review studies relevant to fear extinction, describing the anatomical and functional characteristics of the vagus nerve and mechanisms of vagus nerve stimulation (VNS)-induced memory enhancement and plasticity.

RESULTS

We propose that stimulation of the left cervical vagus nerve during exposure to conditioned cues signals the brain to store new memories just as epinephrine or emotional arousal would do, but bypasses the peripheral sympathetic "fight-or-flight" response.

CONCLUSIONS

In support of this hypothesis, we have found that VNS accelerates extinction and prevents reinstatement of conditioned fear in rats. Finally, we propose future studies targeting the optimization of stimulation parameters and the search for biomarkers of VNS effectiveness that may improve exposure therapy outcomes.

Affective communication during bad news consultation. Effect on analogue patients' heart rate variability and recall

OBJECTIVE

The aim of the study was to investigate the effect of physicians' supportive communication on analogue patients' (APs) heart rate variability (HRV) and recall, while watching a video of palliative treatment being explained to a female patient.

METHODS

Sixty healthy women, acting as APs, were randomly assigned to watch one of two versions (standard vs. affective) of a scripted video-vignette of a bad news consultation to a female patient. The physician's communication differed only in the delivery of four supportive comments. Empathy, support and engagement perception were assessed by three questions. APs' HR was recorded during video-observation and recall was assessed immediately after. HRV was determined through measures defined in time and frequency domains.

RESULTS

Data of 54 APs (27 + 27) were included. The group with supportive communication perceived the physician as more empathic and supportive. Intra- and Inter-group comparisons suggested a greater sense of stress in the standard communication group. Recall did not differ in the two groups.

CONCLUSION AND PRACTICE IMPLICATIONS

Findings show that the use of supportive expressions contribute to the perception of the physician as more empathic, potentially buffer patients' arousal after a bad news announcement, but does not confirm a positive impact on general recall.

Elevated resting blood pressure augments autonomic imbalance in posttraumatic stress disorder

Posttraumatic stress disorder (PTSD) is characterized by increased sympathetic nervous system (SNS) activity, blunted parasympathetic nervous system (PNS) activity, and impaired baroreflex sensitivity (BRS), which contribute to accelerated cardiovascular disease. Patients with PTSD also have chronic stress-related elevations in resting blood pressure (BP), often in the prehypertensive range; yet, it is unclear if elevated resting blood pressure (ERBP) augments these autonomic derangements in PTSD. We hypothesized that compared with normotensive PTSD (N-PTSD), those with ERBP (E-PTSD) have further increased SNS, decreased PNS activity, and impaired BRS at rest and exaggerated SNS reactivity, PNS withdrawal, and pressor responses during stress. In 16 E-PTSD and 17 matched N-PTSD, we measured continuous BP, ECG, muscle sympathetic nerve activity (MSNA), and heart rate variability (HRV) markers reflecting cardiac PNS activity [standard deviation of R-R intervals (SDNN), root mean square of differences in successive R-R intervals (RMSSD), and high frequency power (HF)] during 5 min of rest and 3 min of mental arithmetic. Resting MSNA ( P = 0.943), sympathetic BRS ( P = 0.189), and cardiovagal BRS ( P = 0.332) were similar between groups. However, baseline SDNN (56 ± 6 vs. 78 ± 8 ms, P = 0.019), RMSSD (39 ± 6 vs. 63 ± 9 ms, P = 0.018), and HF (378 ± 103 vs. 693 ± 92 ms², P = 0.015) were lower in E-PTSD versus N-PTSD. During mental stress, the systolic blood pressure response ( P = 0.011) was augmented in E-PTSD. Although MSNA reactivity was not different ( P > 0.05), the E-PTSD group had an exaggerated reduction in HRV during mental stress ( P < 0.05). PTSD with ERBP have attenuated resting cardiac PNS activity, coupled with exaggerated BP reactivity and PNS withdrawal during stress.

Respiratory Sinus Arrhythmia in Cognitive Behavioral Therapy for Posttraumatic Stress Symptoms in Children: Preliminary Treatment and Gender Effects

Cognitive behavioral therapy (CBT) is an efficacious treatment for posttraumatic stress disorder (PTSD) symptoms, but the effect of CBT on physiological indicators is largely unknown. Respiratory sinus arrhythmia (RSA) is an established parasympathetic marker of self-regulatory capacity and stress responsivity. The present study tested if and how resting RSA and RSA reactivity changed following treatment among a sample of children (n = 48) who experienced at least one traumatic event and presented with PTSD symptoms. RSA reactivity was measured in response to personalized trauma-related scripts. Results indicated that changes in RSA after treatment were dependent on pretreatment resting levels of RSA, with individuals with high and low pretreatment resting RSA levels appearing to converge over time in both resting RSA and RSA reactivity by the 3-month follow up. Specific to RSA reactivity, a sex difference was evident, as following treatment, females showed less RSA withdrawal whereas males showed more RSA withdrawal. PTSD symptoms were significantly reduced after CBT but symptom change was not associated with pretreatment resting RSA levels. Overall, these results suggest that there may be multiple physiological patterns within children with PTSD and the direction of the physiological changes after CBT may depend on initial differences in resting RSA levels.

Effect of expressive and neutral writing on respiratory sinus arrhythmia response over time

BACKGROUND AND OBJECTIVES

Parasympathetic activity, as indexed by respiratory sinus arrhythmia (RSA), underlies key aspects of emotional and cognitive self-regulation. Examining time-varying RSA response during expressive writing about trauma may help inform theory about mechanisms of this intervention. The present study investigated changes in RSA during expressive writing.

METHODS

Participants (N = 246, M_age = 21.5 years, 72% female) were randomly assigned to expressive or neutral writing conditions and wrote for three 20-min sessions. RSA was measured continuously during the first and third writing session.

RESULTS

Linear mixed model analyses of RSA changes within and across sessions by writing groups found that neutral writers, but not expressive writers, exhibited change in RSA. The overall RSA changes during expressive and neutral writing are consistent with theory about the relationship between cognitive and emotional processing mechanisms and vagal activation.

LIMITATIONS

As the present study was not a clinical sample selected on trauma exposure, findings should be considered preliminary. Additionally, engagement of affective and cognitive processes was only hypothesized, as manipulation checks were not performed.

CONCLUSIONS

The present study illustrates the benefits of examining changes in RSA over time. Future work with clinical samples should include additional measures and tasks to better define these mechanisms and rule out alternative hypotheses.