Diagnostic criteria for disorders of arousal: A video-polysomnographic assessment

Differential effects of sleep deprivation on sleepwalking: Role of demographic and clinical profiles

BACKGROUND

Although sleepwalking is one of the most prevalent and potentially injurious of the NREM parasomnias, it is still diagnosed primarily based on the patient's clinical history. Early pilot work suggested that sleep deprivation protocols could help obtain a polysomnographically-based (PSG) diagnosis of sleepwalking, but larger studies remain lacking.

METHODS

We compared baseline PSG recordings with those obtained after 25hrs of sleep deprivation in a cohort of 124 consecutively assessed adult sleepwalkers.

RESULTS

When compared to baseline recordings, post-sleep deprivation PSG assessments resulted in nearly twice as many somnambulistic episodes being recorded in the laboratory and significantly increased the proportion of patients (from 48 % to 63 %) experiencing at least one lab-based episode. Moreover, while 17 % of patients experienced a sleepwalking event exclusively during recovery sleep, only 2 % of patients did so solely at baseline. Sleep deprivation had similar facilitating effects on patents' somnambulistic events regardless of age of onset and positive versus negative family history for sleepwalking. Younger age and higher home episode frequency both predicted a positive response to sleep deprivation. A separate group of 17 patients with comorbid sleep disorders showed a similar increase in their proportion experiencing at least one episode during recovery sleep.

CONCLUSION

The results from this large series of sleepwalkers provide strong support for the use of sleep deprivation in facilitating the occurrence of somnambulistic events in the sleep laboratory.

Latency to N3 interruption in arousal disorders

STUDY OBJECTIVES

To help expert witnesses in criminal cases using the "sleepwalking defense," we studied the time of first and last interruptions from stage N3 in patients with arousal disorders, including sexsomnia, as well as their determinants.

METHODS

The epochs of lights off, sleep onset, first N3 interruption (with and without behaviors), and last N3 interruption were determined by videopolysomnography on two consecutive nights in 163 adults with disorders of arousal, including 46 with and 117 without sexsomnia.

RESULTS

The first N3 interruption (independently of concomitant behavior) occurred as early as 8 minutes after sleep onset and within 100 minutes of falling asleep in 95% of cases. The first motor arousal from N3 occurred as early as 25 minutes after lights off time, a timing more variable between participants (between 30 and 60 minutes after lights off time in 25% of participants and within 60 minutes of falling asleep in 50%). These latencies did not differ between the groups with and without sexsomnia. No correlation was found between these latencies and the young age, sex, or clinical severity. The latency of motor arousals was shorter when they were associated with a fast-wave EEG profile and were not preceded by another type of N3 arousal.

CONCLUSIONS

The first motor arousal may occur early in the night in patients with arousal disorders, with or without sexsomnia, suggesting that abnormal behaviors occurring as early as 25 minutes after lights off time in clinical and criminal cases can be a parasomnia manifestation.

Temporal dynamics of awakenings from slow-wave sleep in non-rapid eye movement parasomnia

Non-rapid eye movement parasomnia disorders, also called disorders of arousal, are characterized by abnormal nocturnal behaviours, such as confusional arousals or sleep walking. Their pathophysiology is not yet fully understood, and objective diagnostic criteria are lacking. It is known, however, that behavioural episodes occur mostly in the beginning of the night, after an increase in slow-wave activity during slow-wave sleep. A better understanding of the prospect of such episodes may lead to new insights in the underlying mechanisms and eventually facilitate objective diagnosis. We investigated temporal dynamics of transitions from slow-wave sleep of 52 patients and 79 controls. Within the patient group, behavioural and non-behavioural N3 awakenings were distinguished. Patients showed a higher probability to wake up after an N3 bout ended than controls, and this probability increased with N3 bout duration. Bouts longer than 15 min resulted in an awakening in 73% and 34% of the time in patients and controls, respectively. Behavioural episodes reduced over sleep cycles due to a reduction in N3 sleep and a reducing ratio between behavioural and non-behavioural awakenings. In the first two cycles, N3 bouts prior to non-behavioural awakenings were significantly shorter than N3 bouts advancing behavioural awakenings in patients, and N3 awakenings in controls. Our findings provide insights in the timing and prospect of both behavioural and non-behavioural awakenings from N3, which may result in prediction and potentially prevention of behavioural episodes. This work, moreover, leads to a more complete characterization of a prototypical hypnogram of parasomnias, which could facilitate diagnosis.

From physiological awakening to pathological sleep inertia: Neurophysiological and behavioural characteristics of the sleep-to-wake transition

Sleep inertia refers to the transient physiological state of hypoarousal upon awakening, associated with various degrees of impaired neurobehavioral performance, confusion, a desire to return to sleep and often a negative emotional state. Scalp and intracranial electro-encephalography as well as functional imaging studies have provided evidence that the sleep inertia phenomenon is underpinned by an heterogenous cerebral state mixing local sleep and local wake patterns of activity, at the neuronal and network levels. Sleep inertia is modulated by homeostasis and circadian processes, sleep stage upon awakening, and individual factors; this translates into a huge variability in its intensity even under physiological conditions. In sleep disorders, especially in hypersomnolence disorders such as idiopathic hypersomnia, sleep inertia may be a daily, serious and long-lasting symptom leading to severe impairment. To date, few tools have been developed to assess sleep inertia in clinical practice. They include mainly questionnaires and behavioral tests such as the psychomotor vigilance task. Only one neurophysiological protocol has been evaluated in hypersomnia, the forced awakening test which is based on an event-related potentials paradigm upon awakening. This contrasts with the major functional consequences of sleep inertia and its potentially dangerous consequences in subjects required to perform safety-critical tasks soon after awakening. There is a great need to identify reproducible biomarkers correlated with sleep inertia-associated cognitive and behavioral impairment. These biomarkers will aim at better understanding and measuring sleep inertia in physiological and pathological conditions, as well as objectively evaluating wake-promoting treatments or non-pharmacological countermeasures to reduce this phenomenon.

The parasomnia defense in sleep-related homicide: A systematic review and a critical analysis of the medical literature

This review critically analyzes the forensic application of the Parasomnia Defense in homicidal incidents, drawing from medical literature on disorders of arousal (DOA) and rapid-eye-movement sleep behavior disorder (RBD). A systematic search of PubMed, Scopus, Embase, and Cochrane databases was conducted until October 16, 2022. We screened English-language articles in peer-reviewed journals discussing murders committed during sleep with a Parasomnia Defense. We followed PRISMA guidelines, extracting event details, diagnosis methods, factors influencing the acts, perpetrator behavior, timing, motives, concealment, mental experiences, victim demographics, and court verdicts. Three sleep experts evaluated each case. We selected ten homicides, four attempted homicides, and one homicide/attempted homicide that met inclusion/exclusion criteria. Most cases were suspected DOA as unanimously confirmed by experts. RBD cases were absent. Among aggressors, a minority reported dream-like experiences. Victims were primarily female family members killed in or near the bed by hands and/or with sharp objects. Objective sleep data and important crime scene details were often missing. Verdicts were ununiform. Homicides during DOA episodes, though rare, are documented, validating the Parasomnia Defense's use in forensics. RBD-related fatal aggression seems very uncommon. However, cases often lack diagnostic clarity. We propose updated guidelines to enhance future reporting and understanding of such incidents.

The Clinical Spectrum of the Parasomnias

Parasomnias are defined as abnormal movements or behaviors that occur in sleep or during arousals from sleep. Parasomnias vary in frequency from episodic events that arise from incomplete sleep state transition. The framework by which parasomnias are categorized and diagnosed is based on the International Classification of Sleep Disorders-Third Edition, Text Revision (ICSD-3-TR), published by the American Academy of Sleep Medicine. The recent Third Edition, Text Revision (ICSD-3-TR) of the ICSD provides an expert consensus of the diagnostic requirements for sleep disorders, including parasomnias, based on an extensive review of the current literature.

Sleep Terrors

Sleep terrors, categorized under disorders of arousal, more prevalent in pediatric population, generally are self-limited but sometimes can persist or occur in adulthood. These are primed by factors enhancing homeostatic drive on backdrop of developmental predisposition and are precipitated by factors increasing sleep fragmentation resulting in dissociated state of sleep with some cerebral regions showing abnormal slow wave activity and others fast activity. This phenotypically evolves into abrupt partial arousal with individual arousing from N3 or N2 sleep with behaviors representing intense fear such as crying with autonomic hyperactivity. There is no recollection of the event, and lack of vivid dream mentation although fragmented imagery may be noted. Behavioral management is of prime importance including addressing precipitating factors, family reassurance, safety measures, and scheduled awakenings. Pharmacologic agents such as clonazepam and antidepressants are used infrequently in case of disruptive episodes.

Somnambulism

Somnambulism, also called sleepwalking, classified as a non-rapid eye movement sleep parasomnia, encompasses a range of abnormal paroxysmal behaviors, leading to sleepwalking in dissociated sleep in an altered state of consciousness with impaired judgment and configuring a kind of hierarchical continuum with confusional arousal and night terror. Despite being generally regarded as a benign condition, its potential severity entails social, personal, and even forensic consequences. This comprehensive review provides an overview on the current state of knowledge, elucidating the phenomenon of somnambulism and encompassing its clinical manifestations and diagnostic approaches.

Challenges in diagnosing NREM parasomnias: Implications for future diagnostic classifications

NREM parasomnias are frequent and potentially disabling sleep disorders characterized by recurrent abnormal behaviors emerging from NREM sleep. Recently, several studies provided more detailed clinical and polysomnographic characterization of NREM parasomnia which may enhance the diagnostic process. Several revisions of the diagnostic criteria have been proposed in the classification of sleep disorders, the latest being ICSD-3-TR in 2023 with no changes on NREM parasomnias since ICSD-3 published in 2014. We performed an extensive literature review to assess the evidence on the procedure of its diagnosis. We dissected the inconsistencies and shortcomings in the ICSD-3-TR to propose a revision of the current diagnostic criteria. We highlighted the limits of several clinical criteria which should rather be supportive features than mandatory criteria. Infrared cameras with video-recordings with are promising tools to precisely characterize home episodes. Sensitive and specific polysomnographic markers of NREM parasomnias have been identified and should be considered in future revisions. We also suggest the use of diagnostic specifiers (clinical subtypes, clinical significance, levels of severity, age effect, levels of certainty) to define homogeneous subgroups of patients for therapeutic intervention and research purposes. In conclusion, we advocate for significant changes in the current diagnostic criteria of NREM parasomnias for future classification.

Sleep and epilepsy: A clinical and pathophysiological overview

The interaction between sleep and epilepsy is complex. A better understanding of the mechanisms linking sleep and epilepsy appears increasingly important as it may improve diagnosis and therapeutic strategies in patients with epilepsy. In this narrative review, we aim to (i) provide an overview of the physiological and pathophysiological processes linking sleep and epilepsy; (ii) present common sleep disorders in patients with epilepsy; (iii) discuss how sleep and sleep disorders should be considered in new therapeutic approaches to epilepsy such as neurostimulation; and (iv) present the overall nocturnal manifestations and differential diagnosis between epileptic seizures and parasomnia.

Nocturnal agitation: From sleep state dissociation to sleep-related dissociative state

Nocturnal agitation refers to a broad spectrum of symptoms from simple movements to aggressive behaviors with partial or complete loss of awareness. An accurate identification of its etiology is critical for appropriate therapeutic intervention. In children and young adults, distinguishing between non-rapid eye movement (NREM) sleep parasomnias and psychogenic non-parasomniac manifestations, a condition known as sleep-related dissociative disorder (SRDD), can be challenging. This review aims to summarize current clinical, neurophysiological, and epidemiological knowledge on NREM parasomnia and SRDD, and to present the pathophysiological hypotheses underlying these nocturnal manifestations. Sleepwalking, sleep terror and confusional arousals are the three main presentations of NREM parasomnias and share common clinical characteristics. Parasomniac episodes generally occur 30minutes to three hours after sleep-onset, they are usually short, lasting no more than few minutes and involve non-stereotyped, clumsy behaviors with frequent amnesia. The prevalence of NREM parasomnia decreases from 15-30% in children to 2-4% in adults. Parasomniac episodes are incomplete awakening from the deepest NREM sleep and are characterized by a dissociated brain activity, with a wake-like activation in motor and limbic structures and a preserved sleep in the fronto-parietal regions. SRDD is a less known condition characterized by dramatic, often very long episodes with frequent aggressive and potentially dangerous behaviors. SRDD episodes frequently occur in quiet wakefulness before falling asleep. These dissociative manifestations are frequently observed in the context of psychological trauma. The pathophysiology of SRDD is poorly understood but could involve transient changes in brain connectivity due to labile sleep-wake boundaries in predisposed individuals. We hypothesize that SRDD and NREM parasomnia are forms of sleep-related dissociative states favored by a sleep-wake state dissociation during sleep-onset and awakening process, respectively.

Non-REM Sleep Parasomnias

OBJECTIVE

Non-rapid eye movement (non-REM) parasomnias are common across the lifespan. This article describes the manifestations, diagnosis, and management of non-REM parasomnias in adults and discusses the social implications of these conditions.

LATEST DEVELOPMENTS

Non-REM parasomnias represent a hybrid state of wakefulness and sleep, often triggered by events that increase the frequency of arousals or make it more difficult to fully arouse from sleep. Sleep deprivation, certain medications, and untreated obstructive sleep apnea are known to provoke parasomnias, particularly in those who are genetically predisposed. Non-REM parasomnias include disorders of arousal (ie, sleepwalking, sleep terrors, and confusional arousals), sleep-related eating disorder, and exploding head syndrome. Clinical overlap exists between sleep-related eating disorder and disorders of arousal, suggesting that sleep-related eating disorder may be a fourth disorder of arousal or a manifestation of sleepwalking. Exploding head syndrome is a unique parasomnia of uncertain etiology.

ESSENTIAL POINTS

Non-REM parasomnias can range from minor nuisances to severe, life-altering events. While some patients with non-REM parasomnia experience significant consequences during sleep, wakefulness, or both, non-REM parasomnias do not pose a major risk to most patients. For all patients with non-REM parasomnias, safety should be explicitly discussed and addressed. Nonpharmacologic treatment should be prioritized, as increasing total sleep time, avoiding triggering substances, and treating comorbid sleep disorders is often sufficient for the management of non-REM parasomnias. If symptoms persist despite these interventions, treatment with clonazepam or other medications can be considered.

A case of disorder of arousal with prolonged postarousal hypersynchronous delta activity

Disorder of arousal (DOA) is a form of non-rapid eye movement sleep parasomnia caused by partial or incomplete arousal from deep sleep. Most previous studies of patients with DOA analyzed prearousal hypersynchronous delta activity (HSDA), but few studies have described postarousal HSDA. Herein, we report a 23-year-old man with a history of abrupt arousal during sleep and confused behavior and speech since he was 14 years old. During video electroencephalography monitoring, he had 9 arousal events of getting up, sitting on the bed, looking around, or simple arousal, including eyes open, looking at the ceiling, or head flexion. During all arousal events, the postarousal electroencephalography pattern was prolonged HSDA for approximately 40 seconds. The patient was treated unsuccessfully for more than 2 years with an antiseizure medication (lacosamide); eventually, he responded to clonazepam that was administered for the possibility of DOA. Prolonged rhythmic HSDA without spatiotemporal evolution can appear as a postarousal electroencephalography pattern of DOA. When diagnosing DOA, it is important to recognize that postarousal HSDA can appear as a characteristic electroencephalography pattern of DOA.

CITATION

Kang M, Shin D, Lee HC, Provini F, Jung KY. A case of disorder of arousal with prolonged postarousal hypersynchronous delta activity. J Clin Sleep Med. 2023;19(7):1365-1368.

Spotlight on Sleep Stage Classification Based on EEG

The recommendations for identifying sleep stages based on the interpretation of electrophysiological signals (electroencephalography [EEG], electro-oculography [EOG], and electromyography [EMG]), derived from the Rechtschaffen and Kales manual, were published in 2007 at the initiative of the American Academy of Sleep Medicine, and regularly updated over years. They offer an important tool to assess objective markers in different types of sleep/wake subjective complaints. With the aims and advantages of simplicity, reproducibility and standardization of practices in research and, most of all, in sleep medicine, they have overall changed little in the way they describe sleep. However, our knowledge on sleep/wake physiology and sleep disorders has evolved since then. High-density electroencephalography and intracranial electroencephalography studies have highlighted local regulation of sleep mechanisms, with spatio-temporal heterogeneity in vigilance states. Progress in the understanding of sleep disorders has allowed the identification of electrophysiological biomarkers better correlated with clinical symptoms and outcomes than standard sleep parameters. Finally, the huge development of sleep medicine, with a demand for explorations far exceeding the supply, has led to the development of alternative studies, which can be carried out at home, based on a smaller number of electrophysiological signals and on their automatic analysis. In this perspective article, we aim to examine how our description of sleep has been constructed, has evolved, and may still be reshaped in the light of advances in knowledge of sleep physiology and the development of technical recording and analysis tools. After presenting the strengths and limitations of the classification of sleep stages, we propose to challenge the "EEG-EOG-EMG" paradigm by discussing the physiological signals required for sleep stages identification, provide an overview of new tools and automatic analysis methods and propose avenues for the development of new approaches to describe and understand sleep/wake states.

Home nocturnal infrared video to record non-rapid eye movement sleep parasomnias

To assess the feasibility, the acceptability and the usefulness of home nocturnal infrared video in recording the frequency and the complexity of non-rapid eye movement sleep parasomnias in adults, and in monitoring the treatment response. Twenty adult patients (10 males, median age 27.5 years) with a diagnosis of non-rapid eye movement parasomnia were consecutively enrolled. They had a face-to-face interview, completed self-reported questionnaires to assess clinical characteristics and performed a video-polysomnography in the Sleep Unit. Patients were then monitored at home during at least five consecutive nights using infrared-triggered cameras. They completed a sleep diary and questionnaires to evaluate the number of parasomniac episodes at home and the acceptability of the home nocturnal infrared video recording. Behavioural analyses were performed on home nocturnal infrared video and video-polysomnography recordings. Eight patients treated by clonazepam underwent a second home nocturnal infrared video recording during five consecutive days. All patients had at least one parasomniac episode during the home nocturnal infrared video monitoring, compared with 75% during the video-polysomnography. A minimum of three consecutive nights with home nocturnal infrared video was required to record at least one parasomniac episode. Most patients underestimated the frequency of episodes on the sleep diary compared with home nocturnal infrared video. Episodes recorded at home were often more complex than those recorded during the video-polysomnography. The user-perceived acceptability of the home nocturnal infrared video assessment was excellent. The frequency and the complexity of the parasomniac episodes decreased with clonazepam. Home nocturnal infrared video has good feasibility and acceptability, and may improve the evaluation of the phenotype and severity of the non-rapid eye movement parasomnias and of the treatment response in an ecological setting.

Diagnosis and Management of NREM Sleep Parasomnias in Children and Adults

Non-rapid eye movement (NREM) sleep parasomnias are recurrent abnormal behaviors emerging as incomplete arousals out of NREM sleep. Mounting evidence on NREM sleep parasomnias calls for an update of clinical and therapeutical strategies. In the current review, we summarize the state of the art and provide the necessary background to stimulate a critical revision of diagnostic criteria of disorders of arousal (DoA), the most common NREM sleep parasomnia. In particular, we highlight the poor sensitivity of the diagnostic items related to amnesia and absence of conscious experiences during DoA episodes, encourage the role of video-polysomnography and home-video recordings in the diagnostic and treatment work-up, and suggest three levels of diagnostic certainty based on clinical and objective findings. Furthermore, we highlight current gaps of knowledge that prevent the definition of standard guidelines and future research avenues.

NREM Sleep Parasomnias Commencing in Childhood: Trauma and Atopy as Perpetuating Factors

Objective/Background: Phenotyping of non-rapid-eye-movement (NREM) parasomnias is currently poorly undertaken. This study aimed to determine whether there are differences phenotypically among childhood-, adolescent-, and adult-onset NREM parasomnias continuing into and presenting in adulthood. Patients/Methods: A retrospective, cohort study of patients presenting with NREM parasomnia between 2008 and 2019 (n = 307) was conducted. Disorders included sleepwalking (n = 231), night terrors (n = 150), sexualised behaviour in sleep (n = 50), and sleep-related eating disorder (n = 28). Results: Compared to the adult-onset NREM behaviours group, the childhood- and adolescent-onset groups were more likely to have a family history of NREM behaviours (p < 0.001), experience a greater spectrum of NREM disorders (p = 0.001), and report a history of sleep-talking significantly more frequently (p = 0.014). Atopy was most prevalent in the childhood-onset group (p = 0.001). Those with childhood-onset NREM parasomnias were significantly more likely to arouse from N3 sleep on video polysomnography (p = 0.0003). Psychiatric disorders were more likely to be comorbid in the adult-onset group (p = 0.012). A history of trauma coinciding with onset of NREM behaviours was significantly more common in the childhood- and adolescent-onset groups (p < 0.001). Conclusions: Significant differences exist across childhood-, adolescent-, and adult-onset NREM parasomnia presenting in adulthood. This study suggests that adult-onset slow-wave sleep disorders may be confounded by psychiatric disorders resulting in nocturnal sleep disruption and that unresolved traumatic life experiences perpetuate NREM disorders arising in childhood and comprise one of the strongest external risk factors for triggering and perpetuating these disorders in adolescence.

What respiratory physicians should know about parasomnias

Parasomnias have significant quality-of-life, prognostic and potentially forensic implications for patients and their bed-partners. Identifying key clinical features will accelerate diagnosis and appropriate management for these patients. Parasomnias are undesirable physical events or experiences that arise out of, or during, sleep. They can include movements, behaviours, emotions, perceptions, dreams or autonomic nervous system activity. While more common during childhood, they can persist into, or present de novo, during adulthood. Parasomnias can arise out of non-rapid eye movement (NREM) sleep, as in confusional arousals, sleepwalking, sleep terrors or sleep-related eating disorder, or out of REM sleep, as in REM behaviour disorder, recurrent isolated sleep paralysis or nightmare disorder. Sleep-related hypermotor epilepsy is an important differential diagnosis to consider in patients presenting with a parasomnia. A thorough clinical history, including a collateral history if available, is crucial to identify characteristic clinical features. Video polysomnography is useful to identify macro- and micro-sleep architectural features, characteristic behavioural events, and any concomitant sleep pathologies. Treatment of parasomnias involves a combined approach of pharmacological and non-pharmacological intervention, including safety measures, sleep hygiene and medicines such as clonazepam or melatonin to improve sleep consolidation and reduce behavioural activity. As parasomnias can not only be disruptive for the patient and their bed-partner but have important prognostic or forensic consequences, an understanding of their pathophysiology, clinical features and management is valuable for any respiratory physician who may encounter them.

Educational aims

To understand the common features of NREM and REM parasomnias.To differentiate between the causes of motor behaviours during sleep.To discuss the treatment approach for NREM and REM parasomnias.

Sleep terrors-A parental nightmare

Sleep terrors (STs) are sleep disorders characterized by abrupt arousal from sleep with autonomic hyperactivity and inappropriate behavior. Though a common condition in childhood that usually affects children between 4 and 12 years of age, STs, however, may be present even in adulthood. The exact etiology of STs is not known yet, however, several hypotheses have been proposed over the years, identifying some potential genetic, neurodevelopmental, or other causes. Nevertheless, a useful pathophysiological model identified a common cascade of predisposing, priming, and precipitating factors, which could help to explain and sometimes prevent STs. Establishing a correct diagnosis is mandatory for appropriate management, as several conditions (such as other parasomnias or nocturnal seizures) may mimic STs. Furthermore, we also described some conditions which can be comorbid to STs, like some medical or psychological disorders. A number of treatment options have been proposed, ranging from only sleep hygiene practices to pharmacological therapies; we reviewed some of the most prominent ones. In spite of the fact that STs have long been considered benign disorders, which tend to reduce spontaneously over the years, they may have unexpected consequences on the child but also on the caregivers.

Abnormal timing of slow wave synchronization processes in non-rapid eye movement sleep parasomnias

STUDY OBJECTIVES

Sleepwalking, confusional arousals, and sleep terrors are parasomnias occurring out of non-rapid eye movement (NREM) sleep. Several previous studies have described EEG changes associated with NREM parasomnia episodes, but it remains unclear whether these changes are specific to parasomnia episodes or whether they are part of the normal awakening process. Here we directly compared regional brain activity, measured with high-density (hd-) EEG, between parasomnia episodes and normal awakenings (without behavioral manifestations of parasomnia).

METHODS

Twenty adult patients with non-rapid eye movement parasomnias underwent a baseline hd-EEG recording (256 electrodes) followed by a recovery sleep recording after 25 h of total sleep deprivation, during which auditory stimuli were administered to provoke parasomnia episodes.

RESULTS

Both normal awakenings (n = 25) and parasomnia episodes (n = 96) were preceded by large, steep, and "K-complex-like" slow waves in frontal and central brain regions, and by a concomitant increase in high-frequency EEG (beta) activity. Compared to normal awakenings, parasomnia episodes occurred on a less activated EEG background and displayed higher slow wave activity (SWA) and lower beta activity in frontal and central brain regions after movement onset.

CONCLUSIONS

Our results suggest that non-rapid eye movement awakenings, irrespective of behavioral manifestations of parasomnia episodes, involve an arousal-related slow wave synchronization process that predominantly recruits frontal and central brain areas. In parasomnia episodes, this synchronization process comes into play abnormally during periods of high SWA and is associated with higher SWA after movement onset. Thus, an abnormal timing of arousal-related slow wave synchronization processes could underlie the occurrence of NREM parasomnias.

A Systematic Review of Sleep-Wake Disorder Diagnostic Criteria Reliability Studies

The aim of this article is to provide a systematic review of reliability studies of the sleep-wake disorder diagnostic criteria of the international classifications used in sleep medicine. Electronic databases (ubMed (1946-2021) and Web of Science (-2021)) were searched up to December 2021 for studies computing the Cohen's kappa coefficient of diagnostic criteria for the main sleep-wake disorder categories described in the principal classifications. Cohen's kappa coefficients were extracted for each main sleep-wake disorder category, for each classification subtype, and for the different types of methods used to test the degree of agreement about a diagnosis. The database search identified 383 studies. Fifteen studies were analyzed in this systematic review. Insomnia disorder (10/15) and parasomnia disorder (7/15) diagnostic criteria were the most studied. The reliability of all sleep-wake disorders presented a Cohen's kappa with substantial agreement (Cohen's kappa mean = 0.66). The two main reliability methods identified were "test-retest reliability" (11/15), principally used for International Classification of Sleep Disorders (ICSD), and "joint interrater reliability" (4/15), principally used for Diagnostic and Statistical Manual of Mental Disorders (DSM) subtype diagnostic criteria, in particularl, the DSM-5. The implications in terms of the design of the methods used to test the degree of agreement about a diagnosis in sleep medicine are discussed.

Sleepwalking, sleep terrors, sexsomnia and other disorders of arousal: the old and the new

Disorders of arousal (DOA) is an umbrella term initially covering classical sleepwalking, sleep terrors, and confusional arousals, and now including a wider spectrum of specialised forms of non rapid eye movement (non REM) parasomnias such as sexsomnia, sleep-related eating disorder, and sleep-related choking syndrome. Growing evidence has shown that DOA are not restricted to children but are also prevalent in adults (2%-4% of the adult population). While DOA run in family, genetics studies remain scarce and inconclusive. In addition to the risk of injury on themselves and others (including sexual assaults in sexsomnia), adults with DOA frequently suffer from excessive daytime sleepiness, pain, and altered quality of life. The widespread view of DOA as automatic and amnesiac behaviours has now been challenged by subjective (dream reports) and objective (dream-enacting behaviours documented on video-polysomnography) observations, suggesting that sleepwalkers are 'dream walking' during their episodes. Behavioural, experiential, cognitive, and brain (scalp electroencephalography [EEG], stereo-EEG, high density-EEG, functional brain imaging) data converge in showing a dissociated pattern during the episodes. This dissociated pattern resembles the new concept of local arousal with a wake-like activation in motor and limbic regions and a preserved (or even increased) sleep intensity over a frontoparietal network. EEG and behavioural criteria supporting the DOA diagnosis with high sensitivity and specificity are now available. However, treatment is still based on controlling priming and precipitating factors, as well as on clinicians' personal experience with sedative drugs. Placebo-controlled trials are needed to improve patients' treatment. DOA deserve more attention from sleep researchers and clinicians.

A series of 8 cases of sleep-related psychogenic dissociative disorders and proposed updated diagnostic criteria

STUDY OBJECTIVES

To identify the most relevant clinical and video-polysomnographic characteristics of patients with sleep-related dissociative disorders (SRDDs) and to propose a framework for new diagnostic criteria.

METHODS

We searched potential SRDD cases from the scientific literature and from a database of patients referred for clinical and video-polysomnographic assessment in a single sleep disorders center for disruptive nocturnal behaviors (n = 731). The most relevant clinical and neurophysiological characteristics of the cases were extracted and a descriptive analysis was performed.

RESULTS

Twenty-six SRDD cases (8 new and 18 previously published cases) were reviewed. Almost all cases of SRDDs occurred in a context of past traumatic events or abuse and were associated with at least 1 comorbid psychiatric disorder. We highlighted 4 relevant clinical characteristics of SRDD useful for the differential diagnosis with parasomnias: episodes of long duration of more than 1 hour (90.9%), self-inflicted injuries (83.3%), occurrence while awake close to bedtime (35.7%), and the presence of daytime dissociative symptoms (72.7%). The video-polysomnography documented typical episodes of SRDD with prolonged wakefulness before, during, and after the event in 11/26 cases. New diagnostic criteria for SRDD were proposed, with 3 levels of certainty for the diagnosis based on clinical, video-polysomnographic, and homemade video findings.

CONCLUSIONS

More than 30 years after its formal identification, SRDD is not currently recognized as an official diagnostic entity. We better delineate the clinical and neurophysiological features of SRDD and propose a framework for its reinstatement in the next revisions of the sleep and psychiatric disorders classifications.

CITATION

Lopez R, Lefevre L, Barateau L, Micoulaud-Franchi J-A, Dauvilliers Y, Schenck CH. A series of 8 cases of sleep-related psychogenic dissociative disorders and proposed updated diagnostic criteria. J Clin Sleep Med. 2022;18(2):563-573.

Comorbid parasomnias in narcolepsy and idiopathic hypersomnia: more REM than NREM parasomnias

STUDY OBJECTIVES

To assess the frequency, determinants and clinical impact of clinical NREM and REM parasomnias in adult patients with narcolepsy type 1 (NT1), narcolepsy type 2 (NT2), and idiopathic hypersomnia (IH) compared to healthy controls.

METHODS

Familial and past and current personal parasomnias were assessed by questionnaire and medical interviews in 710 patients (220 NT1, 199 NT2, and 221 IH) and 595 healthy controls.

RESULTS

Except for sleep-related eating disorder (SRED), current NREM parasomnias were rare in all patient groups and controls. SRED was more frequent in NT1 patients (7.9%, vs. 1.8% in NT2 patients, 2.1% in IH patients and 1% in controls) and associated with disrupted nighttime sleep (odds ratio [OR] = 3.9) and nocturnal eating in full awareness (OR = 6.9) but not with sex. Clinical REM sleep behavior disorder (RBD) was more frequent in NT1 patients (41.4%, half being violent) than in NT2 patients (13.2%) and affected men more often than women (OR = 2.4). It was associated with disrupted nighttime sleep, depressive symptoms and antidepressant use. Frequent (>1/week) nightmares were reported by 39% of patients with NT1, 29% with NT2 and 27.8% with IH (vs. 8.3% in controls) and were associated with depressive symptoms in narcolepsy. No parasomnia (except sleep-related hallucinations) worsened daytime sleepiness.

CONCLUSIONS

In patients with central disorders of hypersomnolence, comorbid NREM parasomnias (except SRED) are rare and do not worsen sleepiness. In contrast, REM parasomnias are prevalent (especially in NT1) and associated with male sex, disrupted nighttime sleep, depressive symptoms and antidepressant use.

Does the adenosine deaminase (ADA) gene confer risk of sleepwalking?

Sleepwalking is a common non-rapid eye movement (NREM) parasomnia and a significant cause of sleep-related injuries. While evidence suggest that the occurrence of this condition is partly determined by genetic factors, its pattern of inheritance remains unclear, and few molecular studies have been conducted. One promising candidate is the adenosine deaminase (ADA) gene. Adenosine and the ADA enzyme play an important role in the homeostatic regulation of NREM sleep. In a single sleepwalking family, genome-wide analysis identified a locus on chromosome 20, where ADA lies. In this study, we examined if variants in the ADA gene were associated with sleepwalking. In total, 251 sleepwalking patients were clinically assessed, and DNA samples were compared to those from 94 unaffected controls. Next-generation sequencing of the whole ADA gene was performed. Bio-informatic analysis enabled the identification of variants and assessed variants enrichment in our cohort compared to controls. We detected 25 different coding and non-coding variants, of which 22 were found among sleepwalkers. None were enriched in the sleepwalking population. However, many missense variants were predicted as likely pathogenic by at least two in silico prediction algorithms. This study involves the largest sleepwalking cohort in which the role of a susceptibility gene was investigated. Our results did not reveal an association between ADA gene and sleepwalking, thus ruling out the possibility of ADA as a major genetic factor for this condition. Future work is needed to identify susceptibility genes.

Genetic and demographic predisposing factors associated with pediatric sleepwalking in the Philadelphia Neurodevelopmental Cohort

OBJECTIVES

Sleepwalking is a parasomnia associated with non-rapid eye movement (NREM) sleep and is formally diagnosed using polysomnography (PSG). However, PSG are difficult to perform on children or adolescents due to needed compliance. To understand this condition in youth, few studies have been conducted on a large cohort of youths with a diverse distribution of ages and races to characterize it better in the absence of PSG. The present study aimed to evaluate the prevalence of sleepwalking in youth, as well as associated demographic and genetic characteristics, using questionnaires in a large pediatric cohort.

METHODS

Data from the Philadelphia Neurodevelopmental Cohort (PNC) of 7515 youths aged between 8 and 22 years were used in analyses. Demographic and clinical data, including age, sex, and race, and genetic data from 2753 African American (AA) and 4762 European American (EA) subjects were investigated. The age-wise prevalence of sleepwalking in AA and EA subjects was evaluated. Finally, race-specific genome-wide association (GWAS) analyses of sleepwalking were also performed (N = 155 AA cases and 2598 AA controls; N = 512 EA cases and 4250 EA controls).

RESULTS

Lifetime history of sleepwalking correlated with male sex and EA race. A genetic risk locus that reached genome-wide significance was detected at rs73450744 on chromosome 18 in AA, but not EA youth.

CONCLUSION

The present results suggest that male sex, EA race, and genetic factors may be associated with higher rates of sleepwalking among youth. Future studies should consider these variables to advance understanding of the complex pathogenesis of sleepwalking.

Symptom network analysis of the sleep disorders diagnostic criteria based on the clinical text of the ICSD-3

The third edition of the International Classification of Sleep Disorders (ICSD-3) is the authoritative clinical text for the diagnosis of sleep disorders. An important issue of sleep nosology is to better understand the relationship between symptoms found in conventional diagnostic manuals and to compare classifications. Nevertheless, to our knowledge, there is no specific exhaustive work on the general structure of the networks of symptoms of sleep disorders as described in diagnostic manuals. The general aim of the present study was to use symptom network analysis to explore the diagnostic criteria in the ICSD-3 manual. The ICSD-3 diagnostic criteria related to clinical manifestations were systematically identified, and the units of analysis (symptoms) were labelled from these clinical manifestation diagnostic criteria using three rules ("Conservation", "Splitting", "Lumping"). A total of 37 of the 43 main sleep disorders with 160 units of analysis from 114 clinical manifestations in the ICSD-3 were analysed. A symptom network representing all individual ICSD-3 criteria and connections between them was constructed graphically (network estimation), quantified with classical metrics (network inference with global and local measures) and tested for robustness. The global measure of the sleep symptoms network shows that it can be considered as a small world, suggesting a strong interconnection between symptoms in the ICSD-3. Local measures show the central role of three kinds of bridge sleep symptoms: daytime sleepiness, insomnia, and behaviour during sleep symptoms. Such a symptom network analysis of the ICSD-3 structure could provide a framework for better systematising and organising symptomatology in sleep medicine.

The abrupt shift to slower frequencies after arousal from sleep in healthy young adults

STUDY OBJECTIVES

Post-arousal hypersynchrony (PAH) is an atypical arousal pattern in children's electroencephalography. PAH is an abrupt shift to slower frequencies in arousal-related responses, appearing as slow-wave clusters. In contrast, the prevalence of PAH in healthy young adults is still unknown. Here, we examined the prevalence and characteristics of PAH in healthy young participants.

METHODS

Thirty healthy young participants underwent one night of polysomnography (thirteen females, 22.8 ± 2.0 years [mean ± standard deviation]). We examined the prevalence of PAH as a function of sleep stage, sleep cycle, and time course (the first or the second half). The correlation between PAH and sleep variables was examined. The %N3 was compared for each sleep cycle and time course.

RESULTS

Twenty-eight out of 30 participants exhibited PAH (4.6 ± 4.8 times per night). PAH increased significantly during the first sleep cycle and the first half-sleep period. It was observed only in non-rapid eye movement (NREM) and not in REM sleep. The number of PAHs correlated with the number of arousals and arousal indices. The %N3 increased in the first half-sleep and the first sleep cycle.

CONCLUSIONS

PAH was relatively common in healthy young participants. Since PAH occurred in a state with a high prevalence of %N3, the first sleep cycle, or the first half-sleep, we suggest that PAH may be affected by the sleep homeostasis process. Since PAH occurred only in NREM sleep and correlated with arousal increment, it may have the function of suppressing NREM sleep's cortical arousal.

EEG Patterns Prior to Motor Activations of Parasomnias: A Systematic Review

INTRODUCTION

Non-rapid eye movement (NREM) parasomnias are defined as abnormal nocturnal behaviors that typically arise from the NREM sleep stage 3 during the first sleep cycle. The polysomnographic studies showed an increase in sleep fragmentation and an atypical slow wave activity (SWA) in participants with NREM parasomnias compared to healthy controls. To date, the pathophysiology of NREM parasomnias is still poorly understood. The recent investigation of the EEG patterns immediately before parasomnia events could shed light on the motor activations' processes. This systematic review aims to summarize empirical evidence about these studies and provide an overview of the methodological issues.

METHODS

A systematic literature search was carried out in PubMed, Web of Science, and Scopus, following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). The documents obtained were evaluated using the Newcastle-Ottawa Scale (NOS).

RESULTS

Nine studies were included in the qualitative synthesis. The major evidence revealed an increased slow frequency EEG activity immediately before the motor activations in frontal and central areas and increased beta activity in the anterior cingulate cortices.

DISCUSSION

The investigation of EEG patterns before parasomniac episodes could provide new insight into the study of NREM parasomnia pathophysiology. The high- and low-frequency EEG increase before the episodes could represent a predictive electrophysiological pattern of the motor activations' onset. Overall, identifying specific sleep markers before parasomnias might also help differentiate between NREM parasomnias and other motor sleep disorders. Different methodological protocols should be integrated for overcoming the lack of consistent empirical findings. Thus, future studies should focus on the topographical examination of canonical EEG frequency bands to better understand spatial and time dynamics before the episodes and identify the networks underlying the onset of activations.

Sleep-Related Hypermotor Epilepsy vs Disorders of Arousal in Adults: A Step-Wise Approach to Diagnosis

Disorders of arousal (DoA) and sleep-related hypermotor epilepsy (SHE) are sleep-related events characterized by complex, often bizarre, and violent behaviors. DoA are involuntary motor manifestations of various complexities occurring during incomplete awakening from non-rapid eye movement sleep. SHE is a focal epilepsy characterized by stereotyped hyperkinetic or/and asymmetric tonic/dystonic seizures usually arising from non-rapid eye movement sleep. Even if many aspects regarding DoA and SHE have been clarified, the differential diagnosis remains challenging, because DoA and SHE share some semiologic features and genetic background. The clinical history, collected from the patient and his/her witness, represents the first and common milestone in the diagnosis. Validated questionnaires constitute suitable screening tools that could guide further analysis. The worldwide availability of homemade video recordings has increased the possibility of adding more objective information to the clinical history alone. The confirmed diagnosis relies on video-polysomnographic recording although it requires time, economic resources, and specific skills for the analysis. In this review we propose a simple diagnostic algorithm for the differential diagnosis between DoA and SHE in adults, based on the most updated knowledge, from the simpler tool to the most specific and tailored one.

The Arousal Disorders Questionnaire: a new and effective screening tool for confusional arousals, Sleepwalking and Sleep Terrors in epilepsy and sleep disorders units

BACKGROUND

Arousal Disorders (DoA) include Confusional Arousals, Sleepwalking and Sleep Terrors. DoA diagnosis is mainly clinical but no validated questionnaires exist for DoA screening according to the criteria of the International Classification of Sleep Disorders, Third Edition. Recently our group proposed the Arousal Disorders Questionnaire (ADQ) as a new diagnostic tool for DoA diagnosis. The objective of this study was to evaluate the diagnostic accuracy of the ADQ in a sleep and epilepsy center.

METHODS

One interviewer blinded to clinical and video-polysomnographic (VPSG) data administered the ADQ to 150 patients consecutively admitted to our Sleep and Epilepsy Centers for a follow-up visit. The final diagnosis, according to VPSG recordings of at least one major episode, classified patients either with DoA (DoA group) or with other sleep-related motor behaviors confounding for DoA (nDoA group).

RESULTS

47 patients (31%) composed the DoA group; 56 patients with REM sleep behavior disorder, 39 with sleep-hypermotor epilepsy, six with night eating syndrome, and two with drug-induced DoA composed the nDoA group. The ADQ had a sensitivity of 72% (95% CI: 60-82) and a specificity of 96% (95% CI: 89-98) for DoA diagnosis; excluding the items regarding consciousness and episode recall, sensitivity was 83% (95% CI: 71-90) and specificity 93% (95% CI: 86-97).

CONCLUSIONS

The ADQ showed good accuracy in screening patients with DoA in a sleep and epilepsy center setting. Diagnostic criteria related to cognition and episode recall reduced ADQ sensitivity, therefore a better definition of these criteria is required, especially in adults.

Disorders of Arousal: A Chronobiological Perspective

Non-rapid eye movement (NREM) sleep parasomnias are characterized by motor and emotional behaviors emerging from incomplete arousals from NREM sleep and they are currently referred to as disorders of arousal (DoA). Three main clinical entities are recognized, namely confusional arousal, sleep terror and sleepwalking. DoA are largely present in pediatric populations, an age in which they are considered as transitory, unhabitual physiological events. The literature background in the last twenty years has extensively shown that DoA can persist in adulthood in predisposed individuals or even appear de novo in some cases. Even though some episodes may arise from stage 2 of sleep, most DoA occur during slow wave sleep (SWS), and particularly during the first two sleep cycles. The reasons for this timing are linked to the intrinsic structure of SWS and with the possible influence on this sleep phase of predisposing, priming and precipitating factors for DoA episodes. The objective of this paper is to review the intrinsic sleep-related features and chronobiological aspects affecting SWS, responsible for the occurrence of the majority of DoA episodes during the first part of the night.

Commonalities and Differences in NREM Parasomnias and Sleep-Related Epilepsy: Is There a Continuum Between the Two Conditions?

Introduction: Differential diagnosis between disorders of arousal (DoA) and sleep-related hypermotor epilepsy (SHE) often represents a clinical challenge. The two conditions may be indistinguishable from a semiological point of view and the scalp video-polysomnography is often uninformative. Both disorders are associated with variable hypermotor manifestations ranging from major events to fragments of a hierarchical continuum of increasing intensity, complexity, and duration. Given their semiological overlap we decided to explore the sleep texture of DoA and SHE seeking for similarities and differences.

Methods: We analyzed sleep macrostructure and CAP (cyclic alternating pattern) parameters in a cohort of 35 adult DoA patients, 40 SHE patients and 24 healthy sleepers, all recorded and scored in the same sleep laboratory. Nocturnal behavioral manifestations included minor motor events, paroxysmal arousals and major attacks in SHE, and simple, rising, or complex arousal movements in DoA.

Results: Compared to healthy controls, DoA and SHE showed similar amounts of sleep efficiency, light sleep, deep sleep, REM sleep, CAP subtypes. Both groups also showed slow wave sleep fragmentation and an increased representation of stage N3 in the second part of the night. The only discriminating elements between the two conditions regarded sleep length (more reduced in DoA) and sleep instability (more elevated in SHE). In DoA recordings, all motor episodes arose from NREM sleep: 37% during light NREM stages and 63% during stage N3 (simple arousal movements: 94%). In SHE recordings, 57% of major attacks occurred during stage N3.

Conclusions: So far, emphasis has been placed on the differentiation of sleep-related epilepsy and NREM arousal disorders. However, the impressive analogies between DoA and SHE suggest the existence of an underestimated continuum across the conditions, linked by increased levels of sleep instability, higher amounts of slow wave sleep and NREM/REM sleep imbalance. Sleep texture is extremely similar in the two conditions, although CAP metrics disclose quantitative differences. In particular, SHE patients show a higher arousal instability compared to DoA subjects. Given their clinical and epidemiological overlap, a common genetic background is also hypothesized. In such a perspective, we suggest that the consolidated dichotomy DoA vs. SHE should be reappraised.

Video-Polysomnographic Assessment for the Diagnosis of Disorders of Arousal in Children

OBJECTIVES

To highlight the slow-wave sleep (SWS) fragmentation and validate the video-polysomnographic (vPSG) criteria and cutoffs for the diagnosis of disorders of arousal (DOA) in children, as already reported in adults.

METHODS

One hundred children (66 boys, 11.0 ± 3.3 years) with frequent episodes of DOA and 50 nonparasomniac children (32 boys, 10.9 ± 3.9 years) underwent vPSG recording to quantify SWS characteristics (number of N3 sleep interruptions, fragmentation index, slow/mixed and fast arousal ratios, and indexes per hour) and associated behaviors. We compared SWS characteristics in the 2 groups and defined the optimal cutoff values for the diagnosis of DOA using receiver operating characteristic curves.

RESULTS

Patients with DOA had higher amounts of N3 and REM sleep, number of N3 interruptions, SWS fragmentation, and slow/mixed arousal indexes than controls. The highest area under the curve (AUC) values were obtained for SWS fragmentation and slow/mixed arousal indexes with satisfactory classification performances (AUC 0.80, 95% confidence interval [CI] 0.73-0.87; AUC 0.82, 95% CI 0.75-0.89). SWS fragmentation index cutoff value of 4.1/h reached a sensitivity of 65.0% and a specificity of 84.0%. Slow/mixed arousal index cutoff of 3.8/h reached a sensitivity of 69.0% and a specificity of 82.0%. At least one parasomniac episode was recorded in 63.0% of patients and none of the controls. Combining behavioral component by vPSG increased sensitivity of both biomarkers to 83% and 89%, respectively.

CONCLUSIONS

We confirmed that SWS fragmentation and slow/mixed arousal indexes are 2 relevant biomarkers for the diagnosis of DOA in children, with different cutoffs obtained than those validated in adults.

CLASSIFICATION OF EVIDENCE

This study provides Class III evidence that SWS fragmentation and slow/mixed arousal indexes on vPSG accurately identify children with DOA.

Parasomnias Occurring in Non-Rapid Eye Movement Sleep

PURPOSE OF REVIEW

This article discusses the clinical manifestations, diagnosis and differential diagnosis, pathophysiology, and management of parasomnias occurring in non-rapid eye movement (REM) sleep.

RECENT FINDINGS

Disorders of arousal are characterized by dissociated sleep, with wake and sleep phenomena intermingling, and local sleep, in which different areas of the brain exist simultaneously in different states of wakefulness or sleep. The frequency of arousals from slow-wave sleep with delta or mixed-frequency activity has a high sensitivity but relatively low specificity for the diagnosis of arousal parasomnias.

SUMMARY

Disorders of arousal (sleepwalking, sleep terrors, and confusional arousals) are characterized by incomplete awakenings from slow-wave sleep, limited recall of imagery, and partial or complete amnesia. They occur most frequently in childhood. Management includes correction of precipitating factors, attention to safety, behavioral techniques, and medications. Sleep-related eating disorder is a variant of arousal disorders and may be associated with the use of short-acting hypnotics and restless legs syndrome. Complex nocturnal visual hallucinations can occur with visual loss, dementia with Lewy bodies, use of β-adrenergic receptor antagonists, and anxiety. Exploding head syndrome occurs at wake-sleep transition or on waking during the night, is usually benign, and requires treatment only if significant sleep disruption occurs.

Eyes wide open minds shut best identify disorders of arousal in adult sleepwalkers

Grigg-Damberger M, Foldvary-Schaefer N. Eyes wide open minds shut best identify disorders of arousal in adult sleepwalkers. J Clin Sleep Med. 2020;16(1):7–8.

Update on nonpharmacological interventions in parasomnias

Parasomnias are abnormal behaviors that occur during sleep and can be associated, in particular during adulthood, with impaired sleep quality, daytime dysfunction, and occasionally with violent and harmful nocturnal behaviors. In these cases, therapies are often considered. Longterm pharmacological treatments are not always well tolerated and often have limited efficacy. Therefore, behavioral approaches remain an important treatment option for several types of parasomnias. However, the evidence-based approaches are limited. In the current review, we highlight results from various nonpharmacological techniques on different types of parasomnias and provide a glimpse into the future of nonpharmacological treatments in this field.

Simple behavioral criteria for the diagnosis of disorders of arousal

STUDY OBJECTIVES

This case-control study aimed to identify and validate behavioral markers supporting the diagnosis of disorders of arousal (DOA) with video polysomnography.

METHODS

All behaviors associated with 1,335 episodes of N3 interruptions were compared in 52 adult patients with DOA versus 52 participants without DOA (healthy control patients and patients with insomnia, hypersomnia, or sleep apnea syndrome).

RESULTS

Patients with DOA had more frequent (5.1 ± 2.4 versus 3.4 ± 1.9 interruptions/N3 time) and longer (35.8 ± 33 versus 23.1 ± 21.4 sec) arousals and awakenings from N3 than control patients. In the DOA group, the onset of behaviors was more abrupt, and behaviors including eye opening (69% versus 16%), head raising (41% versus 9%), visually exploring the environment (27% versus 1%), expression of fear/surprise (21% versus zero), speaking (18% versus 0.3%), trunk raising (13% versus 0.3%), and interacting with the environment (13% versus 0.5%), were (unlike quiet, comfort behaviors) more frequent than in control patients. A cutoff of two or more N3 interruptions containing eye opening yielded a sensitivity of 94.2% and a specificity of 76.9% for a DOA diagnosis. This accuracy was confirmed in a second set of data (second night of monitoring). Behaviors including an expression of fear/surprise (67.3%), sitting (32.7%), screaming, and standing up were specific to patients with DOA.

CONCLUSIONS

A simple, behavioral video marker of behavioral reactions during N3 interruption (ie, opening the eyes at least two times in the same night) was sensitive, specific, and reproducible for discriminating patients with DOA from sleep laboratory control patients.

CLINICAL TRIAL REGISTRATION

This study is a surrogate study of NCT02648568 and NCT03074578 on ClinicalTrials.gov.

Disorders of Arousal in adults: new diagnostic tools for clinical practice

Disorders of Arousal  (DOA) are mental and motor behaviors arising from NREM sleep. They comprise a spectrum of manifestations of increasing intensity from confusional arousals to sleep terrors to sleepwalking.

Although DOA in childhood are usually harmless, in adulthood they are often associated with injurious or violent behaviors to the patient or others. Driving motor vehicles, suspected suicide, and even homicide or attempted homicide have been described during sleepwalking in adults. Furthermore, adult DOA need to be differentiated from other sleep disorders such as Sleep-related Hypermotor Epilepsy or REM Sleep Behavior Disorder.

Although many aspects of DOA have been clarified in the last two decades there is still a lack of objective and quantitative diagnostic criteria for DOA.

Recent advances in EEG analysis and in the semiological characterization of DOA motor patterns have provided a better definition of DOA diagnosis.

Our article focuses on the DOA diagnostic process describing accurately the newest DOA clinical, EEG and video-polysomnographic tools in order to aid clinicians in DOA assessment.

NREM sleep parasomnias as disorders of sleep-state dissociation

Non-rapid eye movement (NREM) sleep parasomnias (or NREM parasomnias) are fascinating disorders with mysterious neurobiological substrates. These conditions are common and often severe, with social, personal and forensic implications. The NREM parasomnias include sleepwalking, sleep terrors and confusional arousals - collectively termed disorders of arousal (DOAs) - as well as less well-known entities such as sleep-related sexual behaviours and eating disorders. Affected patients can exhibit waking behaviours arising abruptly out of NREM sleep. Although the individual remains largely unresponsive to the external environment, their EEG shows both typical sleep-like and wake-like features, and they occasionally report dreaming afterwards. Therefore, these disorders offer a unique natural model to explore the abnormal coexistence of local sleep and wake brain activity and the dissociation between behaviour and various aspects of consciousness. In this article, we critically review major findings and updates on DOAs, focusing on neurophysiological studies, and offer an overview of new clinical frontiers and promising future research areas. We advocate a joint effort to inform clinicians and the general public about the management and follow-up of these conditions. We also strongly encourage collaborative multicentre studies to add more objective polysomnographic criteria to the current official diagnostic definitions and to develop clinical practice guidelines, multidisciplinary research approaches and evidence-based medical care.