Dream enactment behavior-a real nightmare: a review of post-traumatic stress disorder, REM sleep behavior disorder, and trauma-associated sleep disorder

Secondary RBD: Not just neurodegeneration

Rapid eye movement sleep behavior disorder is a parasomnia characterized by excessive muscle activity during rapid eye movement sleep (rapid eye movement sleep without atonia), along with dream enactment behavior. Isolated rapid eye movement sleep behavior disorder tends to occur in older males and is of concern due to the known link to Parkinson's disease and other synucleinopathies. When rapid eye movement sleep behavior disorder occurs in association with other neurological or general medical conditions, or resulting from the use of various substances, it is called secondary rapid eye movement sleep behavior disorder; the most common cause is neurodegenerative illness, specifically the synucleinopathies. Here, the focus will be on the subset of secondary rapid eye movement sleep behavior disorder in which there is no neurodegenerative disease.

Opportunities and Pitfalls of REM Sleep Behavior Disorder and Olfactory Dysfunction as Early Markers in Parkinson's Disease

During its pre-motor stage, Parkinson's disease (PD) presents itself with a multitude of non-motor symptoms with different degrees of specificity and sensitivity. The most important among them are REM sleep behavior disorder (RBD) and olfactory dysfunction. RBD is a parasomnia characterized by the loss of REM sleep muscle atonia and dream-enacting behaviors. Olfactory dysfunction in individuals with prodromal PD is usually described as hyposmia (reduced sense of smell) or anosmia (complete loss of olfactory function). These symptoms can precede the full expression of motor symptoms by decades. A close comprehension of these symptoms and the underlying mechanisms may enable early screening as well as interventions to improve patients' quality of life. Therefore, these symptoms have unmatched potential for identifying PD patients in prodromal stages, not only allowing early diagnosis but potentially opening a window for early, possibly disease-modifying intervention. However, they come with certain challenges. This review addresses some of the key opportunities and pitfalls of both RBD and olfactory dysfunction as early markers of PD.

Trauma-Associated Sleep Disorder

Trauma-associated sleep disorder (TASD) is a recently described parasomnia that develops following a traumatic event. It consists of trauma-related nightmares, disruptive nocturnal behaviors, and autonomic disturbances, and shares similarities with post-traumatic stress disorder and rapid eye movement behavior disorder. The underlying pathophysiology of TASD and how it relates to other parasomnias are still not entirely understood; proposed treatment is similarly nebulous, with prazosin at the forefront along with management of comorbid sleep disorders. The purpose of this article is to characterize and highlight the clinical features of this condition.

Vivid dreams are associated with a high percentage of REM sleep: a prospective study in veterans

STUDY OBJECTIVES

Vivid dreams are dreams that feel real or are associated with dream enactment behavior. They are prevalent in veterans, especially in those with psychiatric disorders such as post-traumatic stress disorders. Such psychiatric disorders have known association with abnormalities in rapid eye movement (REM) sleep. Vivid dreams are also described in neurological conditions, such Lewy body dementias, which are also associated with REM sleep abnormality. Although vivid dreams occur in neuropsychiatric disorders that have REM sleep abnormalities, there are no studies that have directly investigated an association between vivid dreams and REM sleep. We sought to study vivid dreams and REM sleep in veterans.

METHODS

Veterans undergoing polysomnography at our hospital were invited to enroll. Participants completed a dream-related questionnaire the morning after their polysomnography.

RESULTS

We prospectively enrolled 505 veterans. After a night in the sleep laboratory, 196 of 504 (39%) reported experiencing a dream, and, of those, 117 of 190 (62%) described their dream as vivid. Discrepancies in patient totals are secondary to missing questionnaire data. Our novel finding is that participants with a high percentage of REM sleep (above 25%) were more than twice likely to report a vivid dream than participants with a lower percentage of REM sleep (P < .0001). Nonvivid dreams were not associated with a high percentage of REM sleep.

CONCLUSIONS

Vivid dreams are associated with a high percentage of REM sleep. Further research into the role of REM sleep abnormalities in vivid dreams may help to advance understanding of neuropsychiatric disorders.

CITATION

Fattal D, Platti N, Hester S, Wendt L. Vivid dreams are associated with a high percentage of REM sleep: a prospective study in veterans. J Clin Sleep Med. 2023;19(9):1661-1668.

Biomarkers of Neurodegeneration in Post-Traumatic Stress Disorder: An Integrative Review

Post-Traumatic Stress Disorder (PTSD) is a chronic psychiatric disorder that occurs following exposure to traumatic events. Recent evidence suggests that PTSD may be a risk factor for the development of subsequent neurodegenerative disorders, including Alzheimer's dementia and Parkinson's disease. Identification of biomarkers known to be associated with neurodegeneration in patients with PTSD would shed light on the pathophysiological mechanisms linking these disorders and would also help in the development of preventive strategies for neurodegenerative disorders in PTSD. With this background, the PubMed and Scopus databases were searched for studies designed to identify biomarkers that could be associated with an increased risk of neurodegenerative disorders in patients with PTSD. Out of a total of 342 citations retrieved, 29 studies were identified for inclusion in the review. The results of these studies suggest that biomarkers such as cerebral cortical thinning, disrupted white matter integrity, specific genetic polymorphisms, immune-inflammatory alterations, vitamin D deficiency, metabolic syndrome, and objectively documented parasomnias are significantly associated with PTSD and may predict an increased risk of subsequent neurodegenerative disorders. The biological mechanisms underlying these changes, and the interactions between them, are also explored. Though requiring replication, these findings highlight a number of biological pathways that plausibly link PTSD with neurodegenerative disorders and suggest potentially valuable avenues for prevention and early intervention.

Sleep-related motor disorders

Sleep-related motor disorders include non-rapid-eye movement (NREM) sleep parasomnias, rapid-eye movement (REM), sleep parasomnias including REM sleep behavior disorder (RBD), isolated motor phenomena in sleep, and periodic limb movement disorder. Restless legs syndrome (RLS) occurs while awake but is closely related to sleep and has a circadian pattern. The pontine sublaterodorsal tegmental nucleus has an important role in aligning motor control with sleep states, and dysfunction in this region can explain motor activities including cataplexy and loss of REM atonia seen in REM sleep behavior disorder. This chapter begins with a review of motor control in sleep. The rest of the chapter summarizes the clinical presentation, epidemiology, differential and treatment of NREM, REM, and isolated sleep-related motor disorders as well as restless legs syndrome.

Clinical and polysomnographic features of trauma associated sleep disorder

STUDY OBJECTIVES

Trauma associated sleep disorder is a proposed parasomnia that develops after trauma with clinical features of trauma related nightmares, disruptive nocturnal behaviors, and autonomic disturbances. The purpose of this case series is to better characterize the clinical and video-polysomnographic features of patients meeting clinical criteria for this proposed parasomnia.

METHODS

Semistructured clinical interview and detailed video-polysomnography review of 40 patients. Movements and vocalizations in rapid eye movement sleep were quantified according to the rapid eye movement sleep behavior disorder severity scale.

RESULTS

Patients (n = 40, 32 males) were service members and veterans with a median age of 38.9 years (range 24-57 years) who reported trauma related nightmares and disruptive nocturnal behaviors at home. On video-polysomnography, 28 (71.8%) patients had disruptive nocturnal behaviors in rapid eye movement sleep consisting of limb, head, and axial movements; vocalizations were present in 8 (20%). On the rapid eye movement sleep behavior disorder severity scale, most (n = 28, 71.8%) had a low rating but those with greater severity (n = 11, 28.2%) had a higher prevalence of posttraumatic stress disorder (P = .013) and markedly less N3 sleep (P = .002). The cohort had a high rate of insomnia (n = 35, 87.5%) and obstructive sleep apnea (n = 19, 47.5%). Most patients were treated with prazosin (n = 29, 72.5%) with concomitant behavioral health interventions (n = 25, 64.1%); 15 (51.7%) patients receiving prazosin reported improved symptomatology.

CONCLUSIONS

Disruptive nocturnal behaviors can be captured on video-polysomnography during rapid eye movement sleep, although they may be less pronounced than what patients report in their habitual sleeping environment. Clinical and video-polysomnographic correlations are invaluable in assessing patients with trauma associated sleep disorder to document objective abnormalities. This case series provides a further basis for establishing trauma associated sleep disorder as a unique parasomnia.

CITATION

Brock MS, Matsangas P, Creamer JL, et al. Clinical and polysomnographic features of trauma associated sleep disorder. J Clin Sleep Med. 2022;18(12):2775-2784.

Exploring the Sensitivity of Prodromal Dementia with Lewy Bodies Research Criteria

Dementia with Lewy bodies (DLB) is an insidious neurodegenerative disease characterised by a precipitous decline in cognition, sleep disturbances, motor impairment and psychiatric features. Recently, criteria for prodromal DLB (pDLB) including clinical features and biomarkers have been put forward to aid the classification and research of this ambiguous cohort of patients. Researchers can use these criteria to classify patients with mild cognitive impairment (MCI) with Lewy bodies (MCI-LB) as either possible (either one core clinical feature or one biomarker are present) or probable pDLB (at least two core clinical features, or one core clinical feature and at least one biomarker present). However, as isolated REM sleep behaviour disorder (iRBD) confirmed with polysomnography (PSG) can be included as both a clinical and a biomarker feature, potentially reducing the specificity of these diagnostic criteria. To address this issue, the current study classified a cohort of 47 PSG-confirmed iRBD patients as probable prodromal DLB only in the presence of an additional core feature or if there was an additional non-PSG biomarker. Thirteen iRBD patients demonstrated MCI (iRBD-MCI). In the iRBD-MCI group, one presented with parkinsonism and was thus classified as probable pDLB, whilst the remaining 12 were classified as only possible pDLB. All patients performed three tasks designed to measure attentional deficits, visual hallucinations and visuospatial impairment. Patients also attended clinical follow-ups to monitor for transition to DLB or another synucleinopathy. Findings indicated that the only patient categorised by virtue of having two core clinical features as probable pDLB transitioned over 28 months to a diagnosis of DLB. The performance of this probable pDLB patient was also ranked second-highest for their hallucinatory behaviours and had comparatively lower visuospatial accuracy. These findings highlight the need for more stringent diagnostic research criteria for pDLB, given that only one of the 13 patients who would have satisfied the current guidelines for probable pDLB transitioned to DLB after two years and was indeed the patient with two orthogonal core clinical features.

Sleep medicine: Practice, challenges and new frontiers

Sleep medicine is an ambitious cross-disciplinary challenge, requiring the mutual integration between complementary specialists in order to build a solid framework. Although knowledge in the sleep field is growing impressively thanks to technical and brain imaging support and through detailed clinic-epidemiologic observations, several topics are still dominated by outdated paradigms. In this review we explore the main novelties and gaps in the field of sleep medicine, assess the commonest sleep disturbances, provide advices for routine clinical practice and offer alternative insights and perspectives on the future of sleep research.

The association of polysomnographic sleep on posttraumatic stress disorder symptom clusters in trauma-exposed civilians and veterans

Study Objectives

Self-reported sleep disturbance has been established as a risk factor and predictor for posttraumatic stress disorder (PTSD); however, less is known about the relationship between objective sleep and PTSD symptom clusters, and the specific role of hyperarousal. The present study examined the relationships between sleep continuity and architecture on PTSD symptom clusters.

Methods

Participants underwent two in-laboratory sleep studies to assess sleep continuity and architecture. They also completed the Clinician-Administered PTSD-IV scale and the Structured Clinical Interview for the DSM-IV to assess for PTSD diagnosis and other psychiatric disorders.

Results

Sleep continuity (i.e. total sleep time, sleep efficiency percent, wake after sleep onset, sleep latency) was significantly related to PTSD Cluster B (reexperiencing) symptom severity (R ² = .27, p < .001). Sleep architecture, specifically Stage N1 sleep, was significantly associated with PTSD Cluster B (t = 2.98, p = .004), C (Avoidance; t = 3.11, p = .003), and D (Hyperarosual; t = 3.79, p < .001) symptom severity independently of Stages N2, N3, and REM sleep. REM sleep variables (i.e. REM latency, number of REM periods) significantly predicted Cluster D symptoms (R ² = .17, p = .002).

Conclusions

These data provide evidence for a relationship between objective sleep and PTSD clusters, showing that processes active during Stage N1 sleep may contribute to PTSD symptomatology in civilians and veterans. Further, these data suggest that arousal mechanisms active during REM sleep may also contribute to PTSD hyperarousal symptoms.This paper is part of the War, Trauma, and Sleep Across the Lifespan Collection. This collection is sponsored by the Sleep Research Society.

Dream-enactment behaviours during the COVID-19 pandemic: an international COVID-19 sleep study

There has been increasing concern about the long-term impact of coronavirus disease 2019 (COVID-19) as evidenced by anecdotal case reports of acute-onset parkinsonism and the polysomnographic feature of increased rapid eye movement sleep electromyographic activity. This study aimed to determine the prevalence and correlates of dream-enactment behaviours, a hallmark of rapid eye movement sleep behaviour disorder, which is a prodrome of α-synucleinopathy. This online survey was conducted between May and August 2020 in 15 countries/regions targeting adult participants (aged ≥18 years) from the general population with a harmonised structured questionnaire on sleep patterns and disorders, COVID-19 diagnosis and symptoms. We assessed dream-enactment behaviours using the Rapid Eye Movement Sleep Behaviour Disorder Single-Question Screen with an additional question on their frequency. Among 26,539 respondents, 21,870 (82.2%) answered all items that were analysed in this study (mean [SD] age 41.6 [15.8] years; female sex 65.5%). The weighted prevalence of lifetime and weekly dream-enactment behaviours was 19.4% and 3.1% and were found to be 1.8- and 2.9-times higher in COVID-19-positive cases, respectively. Both lifetime and weekly dream-enactment behaviours were associated with young age, male sex, smoking, alcohol consumption, higher physical activity level, nightmares, COVID-19 diagnosis, olfactory impairment, obstructive sleep apnea symptoms, mood, and post-traumatic stress disorder features. Among COVID-19-positive cases, weekly dream-enactment behaviours were positively associated with the severity of COVID-19. Dream-enactment behaviours are common among the general population during the COVID-19 pandemic and further increase among patients with COVID-19. Further studies are needed to investigate the potential neurodegenerative effect of COVID-19.

Need for Age-Appropriate Diagnostic Criteria for PTSD

Abstract. Studies in patient or community samples suggest that many older adults who experience clinically significant psychopathology do not fit easily into our existing disorder classification systems. This affects older people with traumatic experiences, who in their senescence report multiple mental disturbances and reduced quality of life. Thus, there is a need to develop age-appropriate diagnostic criteria for posttraumatic stress disorder (PTSD). To date, the new ICD-11 has done this only in a very rudimentary way. This article gives a brief historical overview and names the reasons for these diagnostic problems. Subsequently, it proposes six plus one (male-only) features to be dominant and life-stage specific in older adults: posttraumatic nightmares and reenactments, impaired sleep, painful memories of traumatically lost close persons, hypervigilance including elevated startle response, weakness or asthenia, somatoform pain or chronic primary pain, and in males only: reckless or self-destructive behavior. Finally, it outlines future steps to improve the adequate recognition of clinical presentations of trauma sequelae.

Sleep-related (psychogenic) dissociative disorders as parasomnias associated with a psychiatric disorder: update on reported cases

STUDY OBJECTIVES

To update the literature on the diagnostic category of sleep-related dissociative disorders (SRDDs), involving psychogenic dissociation, since the time of their inclusion in the parasomnias section of the International Classification of Sleep Disorders, second edition, in 2005; to summarize the most salient clinical and video-polysomnographic (vPSG) findings and typical clinical profile from all reported cases; and to provide the rationale for the re-inclusion of the group of SRDDs in future editions of the International Classification of Sleep Disorders.

METHODS

A systematic computerized literature search was conducted searching for SRDDs, nocturnal dissociative disorders, and nocturnal dissociation.

RESULTS

Nine additional cases were identified, with sufficient clinical history and vPSG findings to justify the diagnosis of SRDDs, supplementing the 11 cases cited in the International Classification of Sleep Disorders, second edition, for a total of 20 cases. Twenty-six other cases with vPSG testing were found, with 18 cases reported in abstracts and 8 cases reported in a publication with compelling histories of SRDDs and 2 consecutive vPSG studies, but without the vPSG findings explicitly reported for any case. In more than half of all reported cases, there was objective diagnostic confirmation for SRDDs consisting of the hallmark finding of abnormal nocturnal behaviors arising from sustained electroencephalography wakefulness, or during wake-sleep transitions, without epileptiform activity. These nocturnal behaviors often replicated daytime psychogenic dissociative behaviors. A history of trauma (physical, sexual, emotional) was an almost universal finding, along with major psychopathology. All patients, except for one, had prominent histories of daytime dissociative disorders. Many of the patients were referred on account of a presumed parasomnia.

CONCLUSIONS

Cases of SRDDs continue to be reported, often as a "parasomnia mimic," with psychogenic dissociation being clearly distinguished from physiologic sleep-wake dissociation as found in primary sleep disorders such as narcolepsy, rapid eye movement sleep behavior disorder, etc. Eleven reasons are provided for why the category of SRDDs should be re-included in future editions of the International Classification of Sleep Disorders, and in the parasomnias section.

Disturbed Sleep in PTSD: Thinking Beyond Nightmares

Sleep disturbances frequently co-occur with posttraumatic stress disorder (PTSD). Insomnia and nightmares are viewed as core symptoms of PTSD. Yet, relations between disturbed sleep and PTSD are far more complex: PTSD is linked to a broad range of sleep disorders and disturbed sleep markedly affects PTSD-outcome. This article provides a concise overview of the literature on prevalent comorbid sleep disorders, their reciprocal relation with PTSD and possible underlying neurophysiological mechanisms. Furthermore, diagnostic procedures, standard interventions-particularly first choice non-pharmacological therapies-and practical problems that often arise in the assessment and treatment of sleep disturbances in PTSD are described. Finally, we will present some perspectives on future multidisciplinary clinical and experimental research to develop new, more effective sleep therapies to improve both sleep and PTSD.