Memory suppression trades prolonged fear and sleep-dependent fear plasticity for the avoidance of current fear

Preferential consolidation of emotional reactivity during sleep: A systematic review and meta-analysis

Many studies have investigated whether sleep affects cognitively unmodulated reactivity to emotional stimuli. These studies operationalize emotion regulation by using subjective and/or objective measures to compare pre- and post-sleep reactivity to the same emotional stimuli. Findings have been inconsistent: some show that sleep attenuates emotional reactivity, whereas others report enhanced or maintained reactivity. Across-study methodological differences may account for discrepant findings. To resolve the questions of whether sleep leads to the attenuation, enhancement, or maintenance of emotional reactivity, and under which experimental conditions particular effects are observed, we undertook a synthesized narrative and meta-analytic approach. We searched PubMed, PsycINFO, PsycARTICLES, Web of Science, and Cochrane Library databases for relevant articles, using search terms determined a priori and search limits of language = English, participants = human, and dates = January 2006–June 2021. Our final sample included 24 studies that investigated changes in emotional reactivity in response to negatively and/or positively valenced material compared to neutral material over a period of sleep compared to a matched period of waking. Primary analyses used random effects modeling to investigate whether sleep preferentially modulates reactivity in response to emotional stimuli; secondary analyses examined potential moderators of the effect. Results showed that sleep (or equivalent periods of wakefulness) did not significantly affect psychophysiological measures of reactivity to negative or neutral stimuli. However, self-reported arousal ratings of negative stimuli were significantly increased post-sleep but not post-waking. Sub-group analyses indicated that (a) sleep-deprived participants, compared to those who slept or who experienced daytime waking, reacted more strongly and negatively in response to positive stimuli; (b) nap-exposed participants, compared to those who remained awake or who slept a full night, rated negative pictures less negatively; and (c) participants who did not obtain substantial REM sleep, compared to those who did and those exposed to waking conditions, had attenuated reactivity to neutral stimuli. We conclude that sleep may affect emotional reactivity, but that studies need more consistency in methodology, commitment to collecting both psychophysiological and self-report measures, and should report REM sleep parameters. Using these methodological principles would promote a better understanding of under which conditions particular effects are observed.

Go to Bed and You MIGHT Feel Better in the Morning—the Effect of Sleep on Affective Tone and Intrusiveness of Emotional Memories

Purpose of Review

It is important to examine what effect sleep has after an emotional experience. More knowledge about this topic could help inform us whether there are any potential sleep interventions that could help make sure that memories of negative emotional experiences are processed in the most adaptive manner possible.

Recent Findings

Findings on the role of sleep in altering reactivity to emotional stimuli have been highly varied, with significant findings in opposite directions. A new exciting development in the field is several studies finding that sleep seems to make memories of negative experiences less intrusive.

Summary

This review has mainly aimed to give an overview of the field, and of which issues need to be resolved. We argue for there being a strong need for standardization of how data are analyzed and presented, as well as for better methods for determining to what extent the effects of sleep are specific for a particular memory, or represent general changes in emotional reactivity.

Does Sleep Selectively Strengthen Certain Memories Over Others Based on Emotion and Perceived Future Relevance?

Sleep has been found to have a beneficial effect on memory consolidation. It has furthermore frequently been suggested that sleep does not strengthen all memories equally. The first aim of this review paper was to examine whether sleep selectively strengthens emotional declarative memories more than neutral ones. We examined this first by reviewing the literature focusing on sleep/wake contrasts, and then the literature on whether any specific factors during sleep preferentially benefit emotional memories, with a special focus on the often-suggested claim that rapid eye movement sleep primarily consolidates emotional memories. A second aim was to examine if sleep preferentially benefits memories based on other cues of future relevance such as reward, test-expectancy or different instructions during encoding. Once again, we first focused on studies comparing sleep and wake groups, and then on studies examining the contributions of specific factors during sleep (for each future relevance paradigm, respectively). The review revealed that although some support exists that sleep is more beneficial for certain kinds of memories based on emotion or other cues of future relevance, the majority of studies does not support such an effect. Regarding specific factors during sleep, our review revealed that no sleep variable has reliably been found to be specifically associated with the consolidation of certain kinds of memories over others based on emotion or other cues of future relevance.

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

Increasing evidence supports a close link between REM sleep and the consolidation of emotionally toned memories such as traumatic experiences. In order to investigate the role of sleep for the development of symptoms related to traumatic experiences, beyond experimental models in the laboratory, sleep of acutely traumatised individuals may be examined on the first night after trauma. This might allow us to identify EEG variables predicting the development of posttraumatic stress disorder (PTSD) symptoms, and guide the way to novel sleep interventions to prevent PTSD. Based on our experience, patients' acceptance of polysomnography in the first hours after treatment in an emergency room poses obstacles to such a strategy. Wearable, self-applicable sleep recorders might be an option for the investigation of sleep in the aftermath of trauma. They would considerably decrease the perceived burden for patients and thus increase the likelihood of successful patient recruitment. As one potential sleep intervention, sleep deprivation directly after trauma has been suggested to reduce the consolidation of traumatic memories and hence act as a secondary preventive measure. However, experimental data from sleep deprivation studies in healthy volunteers with the trauma film paradigm have been inconclusive regarding the beneficial or detrimental effects of sleep on traumatic memory processing. Depending on further insights into the role of sleep in traumatic memory consolidation through observational and experimental studies, several options for therapeutic sleep interventions are conceivable: besides behavioural sleep deprivation, selective REM sleep suppression or enhancement by a pharmacological intervention into the serotonergic, noradrenergic or cholinergic systems might provide novel therapeutic options. While REM-modulating drugs have been used with some success for the prevention of PTSD after trauma, they have never been tried before the first night of sleep. In conclusion, more experimental and observational research is needed before sleep interventions are performed in actual trauma victims.

The Fear-Avoidance Components Scale (FACS): Responsiveness to Functional Restoration Treatment in a Chronic Musculoskeletal Pain Disorder (CMPD) Population

OBJECTIVES

To assess the clinical validity and factor structure of the Fear-Avoidance Components Scale (FACS), a new fear-avoidance measure.

MATERIALS AND METHODS

In this study, 426 chronic musculoskeletal pain disorder patients were admitted to a Functional Restoration Program (FRP). They were categorized into 5 FACS severity levels, from subclinical to extreme, at admission, and again at discharge. Associations with objective lifting performance and other patient-reported psychosocial measures were determined at admission and discharge, and objective work outcomes for this predominantly disabled cohort, were assessed 1 year later.

RESULTS

Those patients in the severe and extreme FACS severity groups at admission were more likely to "drop out" of treatment than those in the lower severity groups (P=0.05). At both admission and discharge, the FACS severity groups were highly and inversely correlated with objective lifting performance and patient-reported fear-avoidance-related psychosocial variables, including kinesiophobia, pain intensity, depressive symptoms, perceived disability, perceived injustice, and insomnia (Ps<0.001). All variables showed improvement at FRP discharge. Patients in the extreme FACS severity group at discharge were less likely to return to, or retain, work 1 year later (P≤0.02). A factor analysis identified a 2-factor solution.

DISCUSSION

Strong associations were found among FACS scores and other patient-reported psychosocial and objective lifting performance variables at both admission and discharge. High discharge-FACS scores were associated with worse work outcomes 1 year after discharge. The FACS seems to be a valid and clinically useful measure for predicting attendance, physical performance, distress, and relevant work outcomes in FRP treatment of chronic musculoskeletal pain disorder patients.

The Fear-avoidance Components Scale (FACS): Development and Psychometric Evaluation of a New Measure of Pain-related Fear Avoidance

Pain-related fear avoidance (FA), a common problem for patients with painful medical conditions, involves pain-related catastrophizing cognitions, hypervigilance, and avoidance behaviors, which can ultimately lead to decreased functioning, depression, and disability. Several patient-reported instruments have been developed to measure FA, but they have been criticized for limited construct validity, inadequate item specificity, lack of cutoff scores, and missing important FA components. The Fear-Avoidance Components Scale (FACS) is a new patient-reported measure designed to comprehensively evaluate FA in patients with painful medical conditions. It combines important components of FA found in prior FA scales, while trying to correct some of their deficiencies, within a framework of the most current FA model. Psychometric evaluation of the FACS found high internal consistency (α = 0.92) and high test/retest reliability (r = 0.90-0.94, P < 0.01). FACS scores differentiated between 2 separate chronic pain patient samples and a nonpatient comparison group. When clinically relevant severity levels were created, FACS severity scores were highly associated with FA-related patient-reported psychosocial and objective lifting performance variables. These results suggest that the FACS is a psychometrically strong and reliable measure that can help healthcare providers assess FA-related barriers to function and recovery.

Psychological Effect of an Analogue Traumatic Event Reduced by Sleep Deprivation

STUDY OBJECTIVE

To examine the effect of sleep deprivation compared to sleep, immediately after experimental trauma stimuli on the development of intrusive memories to that trauma stimuli.

DESIGN

Participants were exposed to a film with traumatic content (trauma film). The immediate response to the trauma film was assessed, followed by either total sleep deprivation (sleep deprived group, N = 20) or sleep as usual (sleep group, N = 22). Twelve hours after the film viewing the initial psychological effect of the trauma film was measured and for the subsequent 6 days intrusive emotional memories related to the trauma film were recorded in daily life.

SETTING

Academic sleep laboratory and participants' home environment.

PARTICIPANTS

Healthy paid volunteers.

MEASUREMENTS AND RESULTS

On the first day after the trauma film, the psychological effect as assessed by the Impact of Event Scale - Revised was lower in the sleep deprived group compared to the sleep group. In addition, the sleep deprived group reported fewer intrusive emotional memories (mean 2.28, standard deviation [SD] 2.91) compared to the sleep group (mean 3.76, SD 3.35). Because habitual sleep/circadian patterns, psychological health, and immediate effect of the trauma film were similar at baseline for participants of both groups, the results cannot be accounted for by pre-existing inequalities between groups.

CONCLUSIONS

Our findings suggest that sleep deprivation on one night, rather than sleeping, reduces emotional effect and intrusive memories following exposure to experimental trauma.

Effects of sleep on memory for conditioned fear and fear extinction

Learning and memory for extinction of conditioned fear is a basic mammalian mechanism for regulating negative emotion. Sleep promotes both the consolidation of memory and the regulation of emotion. Sleep can influence consolidation and modification of memories associated with both fear and its extinction. After brief overviews of the behavior and neural circuitry associated with fear conditioning, extinction learning, and extinction memory in the rodent and human, interactions of sleep with these processes will be examined. Animal and human studies suggest that sleep can serve to consolidate both fear and extinction memory. In humans, sleep also promotes generalization of extinction memory. Time-of-day effects on extinction learning and generalization are also seen. Rapid eye movement (REM) may be a sleep stage of particular importance for the consolidation of both fear and extinction memory as evidenced by selective REM deprivation experiments. REM sleep is accompanied by selective activation of the same limbic structures implicated in the learning and memory of fear and extinction. Preliminary evidence also suggests extinction learning can take place during slow wave sleep. Study of low-level processes such as conditioning, extinction, and habituation may allow sleep effects on emotional memory to be identified and inform study of sleep's effects on more complex, emotionally salient declarative memories. Anxiety disorders are marked by impairments of both sleep and extinction memory. Improving sleep quality may ameliorate anxiety disorders by strengthening naturally acquired extinction. Strategically timed sleep may be used to enhance treatment of anxiety by strengthening therapeutic extinction learned via exposure therapy. (PsycINFO Database Record