The Spectral Fingerprint of Sleep Problems in Post-Traumatic Stress Disorder

Abstract

BACKGROUNDSleep problems are a core feature of post-traumatic stress disorder (PTSD). However, a robust objective measure for the sleep disturbance in patients has yet to be found.\n\nMETHODSThe current study assessed EEG power across a wide frequency range and multiple scalp locations, in matched trauma-exposed individuals with and without PTSD, during rapid eye movement (REM) and non-REM (NREM) sleep. In addition, a full polysomnographical evaluation was performed, including sleep staging and assessment of respiratory function, limb movements and heart rate. The occurrence of sleep disorders was also assessed.\n\nRESULTSIn PTSD patients, NREM sleep shows a substantial loss of slow oscillation power and increased higher frequency activity compared to controls. The change is most pronounced in right-frontal brain areas and correlates with insomnia. PTSD REM sleep shows a large power shift in the opposite direction, with increased slow oscillation power in occipital areas, which is strongly related to nightmare activity and to lesser extent with insomnia. These pronounced spectral changes occur in the context of severe subjective sleep problems, increased occurrence of various sleep disorders and modest changes in sleep macrostructure.\n\nCONCLUSIONSThis is the first study to show pronounced changes in EEG spectral topologies during both NREM and REM sleep in PTSD. Importantly, the observed power changes reflect the hallmarks of PTSD sleep problems: insomnia and nightmares and may thus be specific for PTSD. A spectral index derived from these data distinguishes patients from controls with high effect size, bearing promise as a candidate biomarker.