Lipinska M., Timol R., Kaminer D., Thomas K.G.F.
Department of Psychology, University of Cape Town, Cape Town, South Africa
Lipinska, M., Department of Psychology, University of Cape Town, Cape Town, South Africa; Timol, R., Department of Psychology, University of Cape Town, Cape Town, South Africa; Kaminer, D., Department of Psychology, University of Cape Town, Cape Town, South Africa; Thomas, K.G.F., Department of Psychology, University of Cape Town, Cape Town, South Africa
Successful memory consolidation during sleep depends on healthy slow-wave and rapid eye movement sleep, and on successful transition across sleep stages. In post-traumatic stress disorder, sleep is disrupted and memory is impaired, but relations between these two variables in the psychiatric condition remain unexplored. We examined whether disrupted sleep, and consequent disrupted memory consolidation, is a mechanism underlying declarative memory deficits in post-traumatic stress disorder. We recruited three matched groups of participants: post-traumatic stress disorder (n = 16); trauma-exposed non-post-traumatic stress disorder (n = 15); and healthy control (n = 14). They completed memory tasks before and after 8 h of sleep. We measured sleep variables using sleep-adapted electroencephalography. Post-traumatic stress disorder-diagnosed participants experienced significantly less sleep efficiency and rapid eye movement sleep percentage, and experienced more awakenings and wake percentage in the second half of the night than did participants in the other two groups. After sleep, post-traumatic stress disorder-diagnosed participants retained significantly less information on a declarative memory task than controls. Rapid eye movement percentage, wake percentage and sleep efficiency correlated with retention of information over the night. Furthermore, lower rapid eye movement percentage predicted poorer retention in post-traumatic stress disorder-diagnosed individuals. Our results suggest that declarative memory consolidation is disrupted during sleep in post-traumatic stress disorder. These data are consistent with theories suggesting that sleep benefits memory consolidation via predictable neurobiological mechanisms, and that rapid eye movement disruption is more than a symptom of post-traumatic stress disorder. © 2014 European Sleep Research Society.
adult; arousal; article; clinical article; controlled study; correlational study; declarative memory; electroencephalography; female; human; memory consolidation; mental task; posttraumatic stress disorder; predictive value; priority journal; REM sleep deprivation; sleep disorder; sleep quality; sleep stage; memory; post-traumatic stress disorder; REM; sleep; Adult; Case-Control Studies; Electroencephalography; Female; Healthy Volunteers; Humans; Memory; Memory Disorders; Polysomnography; Rape; Retention (Psychology); Sleep Initiation and Maintenance Disorders; Sleep, REM; Stress Disorders, Post-Traumatic; Stress, Psychological