Differential effects of sleep on explicit and implicit memory for potential trauma reminders: findings from an analogue study

Abstract

Background: Recent findings suggest that disruptions of sleep-related memory processing are involved in the development of posttraumatic stress symptoms. More specifically, exposure to an analogue traumatic event resulted in fewer intrusive memories, when it was followed by sleep instead of continued wakefulness. However, competing evidence suggests that sleep deprivation may reduce intrusive re-experiencing. To address these conflicting accounts, we examined how sleepas opposed to partial sleep deprivationmodulates explicit and implicit trauma memory using an analogue procedure. Methods: Healthy participants (N = 41) were assigned to a Sleep or Partial sleep deprivation group. Prior to nocturnal sleep, both groups were exposed to "traumatic" picture stories. After sleep or partial sleep deprivation, participants were subjected to tests of explicit and implicit memory for potential trauma reminders. Thereafter, participants completed an intrusion triggering task that was embedded in a distractor task. Results: Analyses revealed higher explicit memory for potential trauma reminders after sleep as compared to partial sleep deprivation. No group differences were found for implicit memory. Participants responded with fewer intrusions after sleep than following partial sleep deprivation. Conclusions: The current findings support a protective role of sleep in trauma memory processing, which may be evident after the first night of sleep post-trauma. Although more research is needed, our results corroborate the importance of promoting restful sleep in trauma-exposed individuals.

Sleep differentially impacts involuntary intrusions and voluntary recognitions of lab‐analogue traumatic memories

“…According to the theoretical accounts of PTSD, excessive involuntary intrusions could be due to insufficient integration between highly salient traumatic memories and existing autobiographical memory framework (Brewin, 2001; Ehlers & Clark, 2000). Based on converging findings from ours and from previous studies (Kleim et al., 2016; Porcheret et al., 2019; Sopp et al., 2019a; Woud et al., 2018), we consider sleep provides a critical time window for system‐level consolidation and integration to happen, which then reduces involuntary intrusions (Rasch & Born, 2013).…”

REM sleep in acutely traumatized individuals and interventions for the secondary prevention of post-traumatic stress disorder

“…In a follow-up nap study, the same authors did not find differences between sleep and wake conditions in intrusions frequency and level of distress, however, participants with periods of REM sleep experienced fewer and less distressing intrusions than those without REM sleep and those who stayed awake (Kleim & Wilhelm, 2019). This is in line with a study examining the effects of partial sleep deprivation in the second half of the night (in which REM sleep dominates) on memory of traumatic picture stories: both stronger explicit trauma memory and fewer intrusions after sleep than following partial sleep deprivation were observed (Sopp, Brueckner, Schafer, Lass-Hennemann, & Michael, 2019). Our own group is performing a laboratorybased, sleep deprivation study with the trauma film paradigm with the largest cohort of participants so far.…”

Traumatic stress and the circadian system: neurobiology, timing and treatment of posttraumatic chronodisruption

“…Accordingly, several human cohort studies have associated early-life traumatic stress exposure with adult SD years later (Agorastos et al, 2019 , Baiden, Fallon, den Dunnen, & Boateng, 2015 , Greenfield, Lee, Friedman, & Springer, 2011 , Kajeepeta, Gelaye, Jackson, & Williams, 2015 , Lind, Aggen, Kendler, York, & Amstadter, 2016 ). Posttraumatic chronodisruption could negatively influence the traumatic memory encoding and consolidation (Henckens, Hermans, Pu, Joels, & Fernandez, 2009 , Sopp, Brueckner, Schäfer, Lass-Hennemann, & Michael, 2019 ) and at the same time enhance maladaptive neuroendocrine, immune, metabolic and autonomic stress regulation, resulting in the extensive symptomatology and comorbidity of trauma-related disorders (Agorastos et al, 2020 , 2018 , 2019 ; Agorastos, 2017 ; Agorastos et al, 2014 , 2014 ; Boscarino, 2004 ; Entringer et al, 2012 ; Pervanidou, Agorastos, Kolaitis, & Chrousos, 2017 ).

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