An attempt to identify reproducible high-density EEG markers of PTSD during sleep

• Published in: Sleep (New York, N.Y.) Vol. 43; no. 1; p. 1
• Main Authors: Wang, Chao, Ramakrishnan, Sridhar, Laxminarayan, Srinivas, Dovzhenok, Andrey, Cashmere, J David, Germain, Anne, Reifman, Jaques
• Format: Journal Article
• Language: English
• Published: US Oxford University Press 13-01-2020
• Subjects: Analysis; Electrodes; Electroencephalography; Eye movements; Post traumatic stress disorder; Power (Philosophy); Sleep; Sleep deprivation; Sound recordings; sleep; power spectrum; post-traumatic stress disorder; delta activity; topography; hyperarousal; gamma activity; high-density EEG; sleep depth
• ISSN: 0161-8105; 1550-9109
• DOI: 10.1093/sleep/zsz207

Abstract
Study Objectives
We examined electroencephalogram (EEG) spectral power to study abnormalities in regional brain activity in post-traumatic stress disorder (PTSD) during sleep. We aimed to identify sleep EEG markers of PTSD that were reproducible across nights and subsamples of our study population.
Methods
Seventy-eight combat-exposed veteran men with (n = 31) and without (n = 47) PTSD completed two consecutive nights of high-density EEG recordings in a laboratory. We performed spectral-topographical EEG analyses on data from both nights. To assess reproducibility, we used the first 47 consecutive participants (18 with PTSD) for initial discovery and the remaining 31 participants (13 with PTSD) for replication.
Results
In the discovery analysis, compared with non-PTSD participants, PTSD participants exhibited (1) reduced delta power (1–4 Hz) in the centro-parietal regions during nonrapid eye movement (NREM) sleep and (2) elevated high-frequency power, most prominent in the gamma band (30–40 Hz), in the antero-frontal regions during both NREM and rapid eye movement (REM) sleep. These findings were consistent across the two study nights, with reproducible trends in the replication analysis. We found no significant group differences in theta power (4–8 Hz) during REM sleep and sigma power (12–15 Hz) during N2 sleep.
Conclusions
The reduced centro-parietal NREM delta power, indicating reduced sleep depth, and the elevated antero-frontal NREM and REM gamma powers, indicating heightened central arousal, are potential objective sleep markers of PTSD. If independently validated, these putative EEG markers may offer new targets for the development of sleep-specific PTSD diagnostics and interventions.