The sleep physiology of nightmares in veterans with psychological trauma: Evaluation of a dominant model using participant-applied electroencephalography in the home environment.

Nightmares are a core feature of posttraumatic stress disorder, are poorly understood, and are associated with serious negative outcomes. Their biology has been difficult to study, and the feasibility of capturing them in the naturalistic home environment has been poor. This said, the published research and dominant scientific model has focused on nightmares as a manifestation of noradrenergic hyperarousal during rapid eye movement sleep. The current study used at-home, participant-applied devices to measure nightmare physiology in posttraumatic stress disorder treatment-seeking veterans, by examining heartrate measures as indicators of noradrenergic tone, and sleep-stage characteristics and stability in the sleep preceding time-stamped nightmare awakenings. Our data indicate the high feasibility of participant-administered, at-home measurement, and showed an unexpected stability of -rapid eye movement sleep along with no evidence of heartrate elevations in sleep preceding nightmare awakenings. Altogether, these data highlight new opportunities for the study of nightmares while questioning the sufficiency of dominant models, which to date are largely theoretically based.

Bedtime regularity predicts positive affect among veterans with posttraumatic stress disorder: an ecological momentary assessment study.

BACKGROUND: Regularizing bedtime and out-of-bed times is a core component of behavioral treatments for sleep disturbances common among patients with posttraumatic stress disorder (PTSD). Although improvements in subjective sleep complaints often accompany improvements in PTSD symptoms, the underlying mechanism for this relationship remains unclear. Given that night-to-night sleep variability is a predictor of physical and mental well-being, the present study sought to evaluate the effects of bedtime and out-of-bed time variability on daytime affect and explore the optimal window lengths of over which variability is calculated. METHODS: For about 30 days, male U.S. military veterans with PTSD (N = 64) in a residential treatment program provided ecological momentary assessment data on their affect and slept on beds equipped with mattress actigraphy. We computed bedtime and out-of-bed time variability indices with varying windows of days. We then constructed multilevel models to account for the nested structure of our data and evaluate the impact of bedtime and out-of-bed time variability on daytime affect. RESULTS: More regular bedtime across 6-9 days was associated with greater subsequent positive affect. No similar effects were observed between out-of-bed time variability and affect. CONCLUSIONS: Multiple facets of sleep have been shown to differently predict daily affect, and bedtime regularity might represent one of such indices associated with positive, but not negative, affect. A better understanding of such differential effects of facets of sleep on affect will help further elucidate the complex and intertwined relationship between sleep and psychopathology. TRIAL REGISTRATION: The trial retrospectively was registered on the Defense Technical Information Center website: Award # W81XWH-15-2-0005.

Calibrating actigraphy to improve sleep efficiency estimates.

Actigraphy (ACT) can enhance treatment for insomnia by providing objective estimates of sleep efficiency; however, only two studies have assessed the accuracy of actigraphy-based estimates of sleep efficiency (ACT-SE) in sleep-disordered samples studied at home. Both found poor correspondence with polysomnography-based estimates (PSG-SE). The current study tested that concordance in a third sample and piloted a method for improving ACT-SE. Participants in one of four diagnostic categories (panic disorder, post-traumatic stress disorder, comorbid post-traumatic stress and panic disorder and controls without sleep complaints) underwent in-home recording of sleep using concurrent ambulatory PSG and actigraphy. Precisely synchronized PSG and ACT recordings were obtained from 41 participants. Sleep efficiency was scored independently using conventional methods, and ACT-SE/PSG-SE concordance examined. Next, ACT data recorded initially at 0.5 Hz were resampled to 30-s epochs and rescaled on a per-participant basis to yield optimized concordance between PSG- and ACT-based sleep efficiency estimates. Using standard scoring of ACT, the correlation between ACT-SE and PSG-SE across participants was statistically significant (r = 0.35, P < 0.025), although ACT-SE failed to replicate a main effect of diagnosis. Individualized calibration of ACT against a night of PSG yielded a significantly higher correlation between ACT-SE and PSG-SE (r = 0.65, P < 0.001; z = 1.692, P = 0.0452, one-tailed) and a significant main effect of diagnosis that was highly correspondent with the effect on PSG-SE. ACT-based estimates of sleep efficiency in sleep-disordered patients tested at home can be improved significantly by calibration against a single night of concurrent PSG.

Dog ownership may promote cardiometabolic health in U.S. military veterans.

Dog ownership has been associated with reduced cardiovascular and all-cause mortality in civilian epidemiological samples. Associations between dog ownership and cardiometabolic disease were examined in the 2019-2020 wave of the National Health and Resilience in Veterans Study. Dog and cat ownership data were obtained from 3078 Veterans and cross-tabulated with self-reported, professionally diagnosed, heart disease, heart attack, stroke, high blood pressure, diabetes, and high cholesterol. In unadjusted tests, dog ownership was associated with lower rates of heart disease, high blood pressure, diabetes, and high cholesterol, while cat ownership was not. Relative to non-owners, dog owners were younger, were more likely to screen positive for posttraumatic stress disorder and/or major depressive disorder, and more active. Binary logistic regression models of associations between dog ownership and cardiometabolic disease were adjusted for age, sex, trauma load, mood disorder, substance abuse, nicotine abuse, and exercise. After adjustment, dog ownership was still associated with lower odds of hypertension and high cholesterol. Dog ownership also interacted with exercise to lower odds of heart disease and attenuated the effect of trauma load on hypertension. Conversely, age interacted with dog ownership such that odds of diabetes and stroke were higher in older Veterans who owned dogs.

Neighborhood disadvantage is associated with sleep disturbance in a sample of trauma-exposed Veterans.

OBJECTIVES: This study examined associations among neighborhood disadvantage, all-night respiratory sinus arrhythmia, fear of sleep, nightmare frequency, and sleep duration in a sample of trauma-exposed Veterans. METHODS: Participants completed baseline assessments and slept on a mattress actigraphy system for seven nights. Neighborhood disadvantage was assessed with the Area Deprivation Index, a census-based socioeconomic index. Differences between the least and most disadvantaged groups on the sleep variables were analyzed. RESULTS: Data were available from 37 Veterans. Residing in neighborhoods with greater disadvantage was associated with elevated fear of sleep and reduced sleep-period respiratory sinus arrhythmia. No significant differences were observed for nightmare frequency or sleep duration. A regression confirmed that neighborhood context had a significant effect on respiratory sinus arrhythmia, after controlling for other baseline sleep variables. CONCLUSIONS: In this sample of Veterans, sleep context may increase hypervigilance in turn serving as a mechanism by which trauma-induced sleep disruptions are maintained.

Heart rate during sleep in PTSD patients: Moderation by contact with a service dog.

There is growing interest in the potential health benefits of dog ownership in both the lay and scientific communities. Large reductions in risk for cardiovascular disease and all-cause mortality in dog owners relative to non-owners have been observed in epidemiological samples. Persons diagnosed with posttraumatic stress disorder exhibit elevated risk for cardiovascular disease. The current study tested a sample of 45 U.S. military veterans with deployment-related posttraumatic stress disorder employing an intensive, longitudinal, within-subjects design contrasting sleep heart rate on nights with and without a service dog. As participants were engaged in residential psychiatric treatment, sleep opportunities, waking activities, meals, and medications, were consistently scheduled. The primary recording methodology, mattress actigraphy, enabled passive quantification of heart rate over a total sample of 1097 nights. Service dog contact was associated with reduced sleep heart rate especially in participants with more severe PTSD. Longer-term longitudinal studies will be needed to assess the durability and asymptotic magnitude of this effect. An unexpected effect of nights in study was associated with increased heart rate consistent with hospitalization-associated deconditioning.

Longitudinal profiles of sleep during residential PTSD treatment.

We investigated longitudinal profiles of objectively measured sleep periods (SP) over the course of residential treatment for posttraumatic stress disorder (PTSD) in a cohort of U.S. male veterans. Participants (N = 190) slept on mattress-actigraphy systems in a Veterans Affairs (VA) residential PTSD program. The final sample included 4078 sleep periods. Latent class mixed model analyses were used to identify between-subject profiles in sleep period durations, controlling for daily medication intake, over the first fifty days of residency. Logistic regression was used to determine the association of pre-treatment characteristics with identified profiles. Three longitudinal profiles of sleep period characterized most of the sample: 'stable' (56%), 'decreasing' (35%), and 'increasing' (8%). Less severe pre-treatment PTSD avoidance symptoms predicted membership in the 'decreasing' class and increased depression symptoms were predictive of membership in the 'increasing' class. Nearly half of the sample reported a summary change of 1 h or more over the course of the initial 50-nights in the program. Future work is needed to identify how these profiles might drive inpatient treatment decisions regarding the provision of adjunctive sleep-focused treatment such as cognitive-behavioral treatment for insomnia or hypnotic medications.

Sleep Spindles Favor Emotion Regulation Over Memory Consolidation of Stressors in Posttraumatic Stress Disorder.

BACKGROUND: Posttraumatic stress disorder (PTSD) is a trauma-induced condition, characterized by intrusive memories and trauma-associated anxiety. Non-rapid eye movement (NREM) sleep spindles might play a crucial role in learning and consolidating declarative stressor information. However, sleep and possibly sleep spindles are also known to regulate anxiety, suggestive of a dual role for sleep spindles in the processing of stressors. Specifically, in individuals with high PTSD symptom burden, spindles might fail to regulate anxiety levels after exposure and instead might maladaptively consolidate stressor information. METHODS: To disentangle the role of spindles in declarative memory versus anxiety regulation after stressor exposure and to examine the role of PTSD in these processes, we measured nap sleep after a cohort of 45 trauma-exposed participants were exposed to laboratory stress. Participants (high vs. low PTSD symptoms) completed 2 visits: a stress visit involving exposure to negatively valent images before nap and a control visit. In both visits, sleep was monitored via electroencephalography. A stressor recall session occurred after the nap in the stress visit. RESULTS: Stage 2 NREM (NREM2) spindle rates were higher in stress versus control sleep, indicative of stress-induced changes in spindles. In participants with high PTSD symptoms, NREM2 spindle rates in stress sleep predicted poorer recall accuracy of stressor images relative to participants with low PTSD symptoms, while correlating with greater reduction in stressor-induced anxiety levels after sleep. CONCLUSIONS: Contrary to our expectations, although spindles are known to play a role in declarative memory processes, our findings highlight an important role for spindles in sleep-dependent anxiety regulation in PTSD.

Autonomic regulation during sleep in PTSD.

The following article reviews the existing data on autonomic nervous system status in posttraumatic stress disorder. This review is embedded in a framework that considers the comparative ethology of sleep under threat. In sum, the current literature, though still quite limited, supports a role for impaired parasympathetic drive but not for increased sympathetic drive in the periphery during sleep in PTSD. Understanding this domain better can be expected to provide insights into the elevated prevalence of cardiovascular disease in posttraumatic stress disorder (PTSD) and may help to identify as-yet unrecognized medical comorbidities. Measurement issues and future opportunities are considered.

Reading the mind in the eyes in PTSD: Limited Moderation by the presence of a service dog.

Persons with posttraumatic stress disorder (PTSD) frequently experience relationship failures in family and occupational domains resulting in loss of social supports. Prior research has implicated impairments in social cognition. The Reading the Mind in the Eyes Test (RMET) measures a key component of social cognition, the ability to infer the internal states of other persons based on features of the eyes region of the face; however, studies administering this popular test to persons with PTSD have yielded mixed results. This study assessed RMET performance in 47 male U.S. military Veterans with chronic, severe PTSD. Employing a within-subjects design that avoided selection biases, it aimed specifically to determine whether components of RMET performance, including accuracy, response latency, and stimulus dwell time, were improved by the company of a service dog, an intervention that has improved social function in other populations. RMET accuracies and response latencies in this PTSD sample were in the normal range. The presence of a familiar service dog did not improve RMET accuracy, reduce response latencies, or increase dwell times. Dog presence increased the speed of visual scanning perhaps consistent with reduced social fear.

The relationship of fear-potentiated startle and polysomnography-measured sleep in trauma-exposed men and women with and without PTSD: testing REM sleep effects and exploring the roles of an integrative measure of sleep, PTSD symptoms, and biological sex.

STUDY OBJECTIVES: Published research indicates that sleep is involved in emotional information processing. Using a fear-potentiated startle (FPS) and nap sleep protocol, we examined the relationship of emotional learning with REM sleep (REMS) in trauma-exposed participants. We also explored the roles of posttraumatic stress disorder (PTSD) symptoms, biological sex, and an integrative measure of polysomnography-measured (PSG) sleep in the learning-sleep relationship. METHODS: After an adaptation nap, participants (N = 46) completed two more visits (counterbalanced): a stress-condition visit, which included FPS conditioning procedures prior to a nap and assessment of learning retention and fear extinction training after the nap, and a control visit, which included a nap opportunity without stressful procedures. FPS conditioning included a "fear" visual stimulus paired with an air blast to the neck and a "safety" visual stimulus never paired with an air blast. Retention and extinction involved presentation of the visual stimuli without the air blast. Primary analyses examined the relationship between FPS responses pre- and post-sleep with stress-condition REMS duration, controlling for control-nap REMS duration. RESULTS: Higher safety learning predicted increased REMS and increased REMS predicted more rapid extinction learning. Similar relationships were observed with an integrative PSG sleep measure. They also showed unexpected effects of PTSD symptoms on learning and showed biological sex effects on learning-sleep relationships. CONCLUSIONS: Findings support evidence of a relationship between adaptive emotional learning and REMS. They underscore the importance of examining sex effects in sleep-learning relationships. They introduce an integrative PSG sleep measure with potential relevance to studies of sleep and subjective and biological outcomes.

Tracking positive and negative affect in PTSD inpatients during a service dog intervention.

Though popular across many audiences, engagement with a service dog has undergone limited empirical evaluation as a complementary or alternative treatment for posttraumatic stress disorder (PTSD). The present study took advantage of a service dog training intervention underway in a Department of Veterans Affairs residential PTSD treatment program to perform a within-subjects comparison of a range of phenotypic markers. The present report considers negative and positive affect, assessed throughout the day, contrasting weeks when participants were or were not accompanied by their service dog. Fifty-four veterans were studied for 2-6 weeks. Negative and positive affect were sampled five times per day using items from the Positive and Negative Affect Schedule. Participants also wore a single-patch ECG/activity recorder and slept on beds recording sleep actigraphically. Linear mixed effects regression was employed to estimate the effect of the presence of service dog on momentary affect in the context of other presumable influences. Missing data were managed using methods applicable to random and nonrandom missingness. In this sample, the presence of a service dog was associated with reduced negative and increased positive affect, with both effects diminishing over time. Only negative affect was associated with time in residential treatment, and only positive affect was associated with concurrent heart rate, activity, and the interaction of activity and prior-night actigraphic sleep efficiency. These results concur with prior reports of reduced PTSD symptomology in association with the presence of a service dog, and with the distinct neurocircuitries underlying defensive and appetitive emotion and motivation. Limitations derive from the artificial environment and brief duration of study. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Regional gray matter oligodendrocyte- and myelin-related measures are associated with differential susceptibility to stress-induced behavior in rats and humans.

Individual reactions to traumatic stress vary dramatically, yet the biological basis of this variation remains poorly understood. Recent studies demonstrate the surprising plasticity of oligodendrocytes and myelin with stress and experience, providing a potential mechanism by which trauma induces aberrant structural and functional changes in the adult brain. In this study, we utilized a translational approach to test the hypothesis that gray matter oligodendrocytes contribute to traumatic-stress-induced behavioral variation in both rats and humans. We exposed adult, male rats to a single, severe stressor and used a multimodal approach to characterize avoidance, startle, and fear-learning behavior, as well as oligodendrocyte and myelin basic protein (MBP) content in multiple brain areas. We found that oligodendrocyte cell density and MBP were correlated with behavioral outcomes in a region-specific manner. Specifically, stress-induced avoidance positively correlated with hippocampal dentate gyrus oligodendrocytes and MBP. Viral overexpression of the oligodendrogenic factor Olig1 in the dentate gyrus was sufficient to induce an anxiety-like behavioral phenotype. In contrast, contextual fear learning positively correlated with MBP in the amygdala and spatial-processing regions of the hippocampus. In a group of trauma-exposed US veterans, T1-/T2-weighted magnetic resonance imaging estimates of hippocampal and amygdala myelin associated with symptom profiles in a region-specific manner that mirrored the findings in rats. These results demonstrate a species-independent relationship between region-specific, gray matter oligodendrocytes and differential behavioral phenotypes following traumatic stress exposure. This study suggests a novel mechanism for brain plasticity that underlies individual variance in sensitivity to traumatic stress.

Hippocampal volume and declarative memory function in combat-related PTSD.

The proposition that declarative memory deficits are systematically related to smaller hippocampal volume was tested in a relatively large sample (n = 95) of U.S. military veterans with and without combat-related posttraumatic stress disorder. This correlative analysis was extended by including multiple measures of verbal and visual declarative memory and multiple memory-relevant regional brain volumes that had been shown to exhibit main effects of PTSD in prior work. Small-to-moderate effects were observed on verbal declarative memory in line with a recent meta-analysis; nevertheless, little or no evidence of systematic linear covariation between memory measures and brain volumes was observed.

Sleep patterns and sleep-related factors between caregiving and non-caregiving women.

This exploratory study compared objective sleep patterns and sleep-related factors between caregiving and non-caregiving women with sleep impairments, and compared the sleep patterns of the caregivers with their care recipients. Nine women caring for adults with dementia and a comparison sample of 34 non-caregiving women provided three nights of in-home polysomnography (PSG) and self-report questionnaires of sleep quality and physical and emotional well-being. Care recipients' sleep was monitored with actigraphy on the same nights of the caregivers' PSG. Caregivers and non-caregivers' sleep patterns were similar across most PSG-measured parameters. Caregivers perceived more sleep disturbances, but PSG showed minimal differences compared to non-caregivers. Caregivers reported more depressive symptoms, and depression was strongly correlated with longer sleep latency. Caregiver's sleep quantity was highly correlated with the sleep quantity of their care recipient. The results suggest that, in this sample, caregivers' sleep was not significantly different from the non-caregiving women, despite differences in perceptions. Although the sample is small, this exploratory study supports the use of multiple nights of in-home PSG to assess caregiver sleep and provides more data on sleep patterns of female dementia caregivers and their relatives.

Increased epoch-to-epoch parasympathetic cardiac regulation in participants with posttraumatic stress disorder compared to those with panic disorder and control participants.

BACKGROUND: Research on the link between respiratory sinus arrhythmia (RSA) and posttraumatic stress disorder (PTSD) has largely focused on average levels of RSA. However, given that rapid shifts in parasympathetic tone are necessary to maintain adaptive cardiac variability, the exclusive focus on these tonic estimates provides an incomplete quantification of parasympathetic cardiac regulation. METHOD: The present study is a secondary analysis of previously published data. This analysis aimed to address this limitation by examining the dynamic regulatory effect of the parasympathetic nervous system on heart rate. As such, we examined epoch-to-epoch parasympathetic cardiac regulation - operationalized as the lagged relationship between RSA and heart rate (HR) across consecutive 30-s epochs - across a single night in participants with PTSD, panic disorder (PD), comorbid PTSD and PD (PTSD + PD), and healthy controls. Electrocardiogram and respiratory signals were continuously recorded from 23 participants with PTSD, 14 with PD, 16 with PTSD + PD, and 16 control participants over a single night of sleep in a laboratory setting. RESULTS: No group differences in tonic RSA were observed; however, participants with PTSD only and PTSD + PD exhibited significantly greater epoch-to-epoch parasympathetic cardiac regulation over the night than those with PD only and control participants. Moreover, greater severity of hyperarousal symptoms was significantly associated with increased epoch-to-epoch parasympathetic cardiac regulation among participants with PTSD only and PTSD + PD. DISCUSSION: These data provide preliminary evidence for an upregulatory parasympathetic response to self-reported hyperarousal in participants with PTSD only and PTSD + PD reflected by increased epoch-to-epoch parasympathetic cardiac regulation.

Sleep/Wake Detection by Behavioral Response to Haptic Stimuli.

STUDY OBJECTIVES: Actigraphy, the tool of choice for assessment of sleep phase disorders, is insensitive to movement-free waking. This study aimed to determine whether the detection of waking could be performed by recording instrumental responses to haptic stimuli delivered by a low-cost device. METHODS: Twenty adults underwent 2 nights of laboratory polysomnography (PSG) while wearing a fingerless glove under which a stimulating actigraph ("Wakemeter") was apposed to the palm. The Wakemeter, controlled by a tablet computer, delivered gentle, haptic stimuli every 10 minutes during the sleep period. If a stimulus was detected, the participant squeezed the Wakemeter. Stimulus times, response times and movements were streamed to the tablet. Concurrent PSG data were scored blind to stimuli and responses. Self-reported sleep quality ratings were collected each morning. RESULTS: The Wakemeter was acceptable to 19 of 20 participants, and effects on self-reported and objective sleep were small. The probability of a response to the stimulus during a wake epoch was high regardless of movement. In contrast, actigraphy magnitude distributions were indistinguishable across epochs scored wake without movement versus sleep, confirming a known limitation of actigraphy. A simple method for calculating sleep efficiency from responses to the stimuli yielded estimates that were highly correlated with PSG-derived estimates (rho = .69, P < .001). CONCLUSIONS: Behavioral responses to haptic stimuli detected epochs of movement-free wake during the sleep period and may augment actigraphy in the low-burden estimation of sleep efficiency. Acceptability of the method over longer recording periods remains to be established.

Effects of moderate-intensity exercise on polysomnographic and subjective sleep quality in older adults with mild to moderate sleep complaints.

BACKGROUND: This study sought to determine the 12-month effects of exercise increases on objective and subjective sleep quality in initially inactive older persons with mild to moderate sleep complaints. METHODS: A nonclinical sample of underactive adults 55 years old or older (n=66) with mild to moderate chronic sleep complaints were randomly assigned to a 12-month program of primarily moderate-intensity endurance exercise (n=36) or a health education control program (n=30). The main outcome measure was polysomnographic sleep recordings, with additional measures of subjective sleep quality, physical activity, and physical fitness. Directional hypotheses were tested. RESULTS: Using intent-to-treat methods, at 12 months exercisers, relative to controls, spent significantly less time in polysomnographically measured Stage 1 sleep (between-arm difference=2.3, 95% confidence interval [CI], 0.7-4.0; p=003), spent more time in Stage 2 sleep (between-arm difference=3.2, 95% CI, 0.6-5.7; p=.04), and had fewer awakenings during the first third of the sleep period (between-arm difference=1.0, 95% CI, 0.39-1.55; p=.03). Exercisers also reported greater 12-month improvements relative to controls in Pittsburgh Sleep Quality Index (PSQI) sleep disturbance subscale score (p=.009), sleep diary-based minutes to fall asleep (p=.01), and feeling more rested in the morning (p=.02). CONCLUSIONS: Compared with general health education, a 12-month moderate-intensity exercise program that met current physical activity recommendations for older adults improved some objective and subjective dimensions of sleep to a modest degree. The results suggest additional areas for investigation in this understudied area.

Two Independent Predictors of Nightmares in Posttraumatic Stress Disorder.

STUDY OBJECTIVES: Understanding nightmares (NM) and disturbing dreams (DD) in posttraumatic stress disorder (PTSD) has been limited by the unpredictability of these events and their nonappearance in the sleep laboratory. This study used intensive, longitudinal, ambulatory methods to predict morning reports of NM/DD in veterans in whom chronic, severe PTSD was diagnosed. METHODS: Participants were 31 male United States military veterans engaged in residential treatment for PTSD and participating in a service animal training intervention. Participants slept on mattress actigraphs and provided reports of momentary mood, as well as morning NM/DD reports, for up to 6 weeks. Mattress actigraphy provided sleep-period heart rate and respiratory sinus arrhythmia (RSA), and an actigraphic estimate of sleep efficiency. On one night, a respiratory event index (REI) was obtained using an ambulatory system. RESULTS: A total of 468 morning reports were obtained, of which 282 endorsed NM/DD during the prior night, and 186 did not. After accounting for multiple predictors, only elevated REI and lower prior-night sleep RSA predicted morning endorsement of NM/DD. These two predictors did not interact. CONCLUSIONS: Elevated REI and lower sleep period RSA were independently predictive of NM/DD. The former result is consistent with studies showing that sleep-disordered breathing (SDB) is a factor in NM/DD, and that continuous positive airway pressure (CPAP) can reduce these symptoms in patients with comorbid PTSD and SDB. The latter result implicates dysregulated arousal modulation during sleep in trauma-related NM/DD. It is consistent with findings that NM/DD are reported in patients without SDB and can persist in patients with comorbid PTSD and SDB even when CPAP successfully remediates SDB.