Mellman TA, Kobayashi I, Lavela J, Wilson B, Hall Brown TS. A relationship between REM sleep measures and the duration of posttraumatic stress disorder in a young adult urban minority population.

Discrepancies between subjectively and objectively measured sleep parameters were not associated with trauma exposure or PTSD. This challenges prior assertions that individuals with PTSD overreport their sleep disturbances.

Posttraumatic stress disorder (PTSD) has been associated with heightened nocturnal autonomic nervous system (ANS) arousal and sleep disturbances. It has been suggested that relationships between sleep and nocturnal ANS activity are influenced by insomnia; however, investigation of this relationship has been limited in PTSD. This study examined nocturnal ANS activity and its relationship to sleep in PTSD and resilience. Physically healthy young adult African Americans with current PTSD (n = 20) or who had never had PTSD despite exposure to a high-impact traumatic event (resilient, n = 18) were monitored with ambulatory electrocardiograms and actigraphy for 24-hr periods. Frequency-domain heart-rate variability measures, that is, low-frequency to high-frequency ratios (LF/HF), which index sympathetic nervous system activity, and normalized HF (nHF), which indexes parasympathetic nervous system activity were examined. Normalized HF during the time-in-bed period was lower for those with PTSD than those with resilience (p = .041). Total sleep time was strongly correlated with time-in-bed LF/HF (r = -.72) and nHF (r = .75) in the resilient group, but these were not correlated in the PTSD group. The results suggest elevated nocturnal ANS arousal and dissociation between ANS activity and total sleep time in PTSD.

Background Blunted nocturnal blood pressure (BP) dipping is an early marker of cardiovascular risk that is prevalent among African Americans. Purpose We evaluated relationships of BP dipping to neighborhood and posttraumatic stress and sleep in urban residing young adult African Americans. Methods One hundred thirty six Black, predominately African American, men and women with a mean age of 22.9 (SD = 4.6) filled out surveys, were interviewed and had two, 24-hour ambulatory BP recordings. Results Thirty eight percent had BP dipping ratios < .10. Wake after sleep onset (WASO), neighborhood disorder and neighborhood poverty rates but not posttraumatic stress symptoms, and other sleep measures, correlated significantly with dipping ratios. Models with the neighborhood measures that also included WASO increased the explained variance. Conclusions Studies elucidating mechanisms underlying effects of neighborhoods on BP dipping and the role of disrupted sleep, and how they can be mitigated are important directions for future research.

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