Non-rapid Eye Movement Parasomnias Research Articles

Dreaming Characteristics in Non-Rapid Eye Movement Parasomnia and Idiopathic Rapid Eye Movement Sleep Behaviour Disorder: Similarities and Differences.

Speech graph analysis (SGA) of dreams has recently shown promise as an objective and language-invariant diagnostic tool that can aid neuropsychiatric diagnosis. Whilst the notion that dreaming mentations reflect distinct physiologic processes is not new, such studies in patients with sleep disorders remain exceptionally scarce. Here, using SGA and other dream content analyses, we set to investigate structural and thematic differences in morning dream recalls of patients diagnosed with Non-Rapid Eye Movement Parasomnia (NREMP) and Idiopathic REM Sleep Behavior Disorder (iRBD). A retrospective cross-sectional study of morning dream recalls of iRBD and NREMP patients was undertaken. Traditional dream content analyses, such as Orlinsky and Hall and Van de Castle analyses, were initially conducted. Subsequently, SGA was performed in order to objectively quantify structural speech differences between the dream recalls of the two patient groups. Comparable rate of morning recall of dreams in the sleep laboratory was recorded; 25% of iRBD and 18.35% of NREMP patients. Aggression in dreams was recorded by 28.57% iRBD versus 20.00% in NREMP group. iRBD patients were more likely to recall dreams (iRBD vs NREMP; P = 0.007), but they also had more white dreams, ie having a feeling of having dreamt, but with no memory of it. Visual and quantitative graph speech analyses of iRBD dreams suggested stable sequential structure, reflecting the linearity of the chronological narrative. Conversely, NREMP dream reports displayed more recursive, less stable systems, with significantly higher scores of graph connectivity measures. The findings of our exploratory study suggest that iRBD and NREMP patients may not only differ on what is recalled in their dreams but also, perhaps more strikingly, on how dreams are recalled. It is hoped that future SGA-led dream investigations of larger groups of patients will help discern distinct mechanistic underpinnings and any associated clinical implications.

Is Sleep-Related Eating Disorder (SRED) a NREM Parasomnia or a Heterogenous Disease?

Sleep-related eating disorder (SRED) is a relatively rare but probably underestimated disorder, where affected patients exhibit nocturnal eating episodes with impaired consciousness and subsequent amnesia. SRED has originally been classified as NREM (non-rapid eye movement) parasomnia, with an obviously high number of concomitant sleep disorders. We suggest that SRED may represent a heterogenous disease, based on accumulating data in recent studies. Some SRED patients may be better classified as sleep-related movement disorders with an underlying dopaminergic dysfunction. Hypnotic drugs may play a crucial role in triggering amnestic SRED in both parasomnic and sleep-related movement-disordered SRED.

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.

Case report: A young man with non-rapid eye movement parasomnias in a KCNT1-related epilepsy family

Case report: A young man with non-rapid eye movement parasomnias in a KCNT1-related epilepsy family

Non-REM Sleep Parasomnias.

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. 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. 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.

1036 Traumatic Complications of Unrecognized Somnambulance in a Pediatric Patient

Abstract Introduction Parasomnias are unusual, disruptive, and abnormal verbal or motor events that occur during sleep or between wake and sleep transitions. They can occur in non-rapid eye movement (NREM) or rapid eye movement (REM) sleep stages. NREM parasomnias are typically more prevalent in pediatric populations. One such NREM parasomnia is sleep walking or somnambulance. One study estimates somnambulance has a prevalence of 17% in ages 3-13 years¹. Somnambulance typically occurs during stage 3 sleep which is clustered in the first half of sleep when REM is less prevalent Report of case(s) A 4-year-old previously healthy male presented to clinic for a somnambulance consult. Around 6 months prior, his parents awoke around 3 AM to check on their crying infant, a sibling of our patient, and noticed the patient was missing. They noticed the back door open. Two blocks away they saw police lights and found he had been hit by a vehicle. He was admitted to the hospital for polytrauma, including bilateral pulmonary contusions with acute respiratory failure, grade 4 liver and kidney lacerations, grade 3 adrenal injury, and right parietal lobe parenchymal and subarachnoid hemorrhages. He was later discharged in stable condition with persistent but improved spasticity, impaired mobility, and cognition. His parents had not noticed any prior episodes of somnambulance. However, they did report other frequent parasomnias: somniloquy and confusional arousals. These episodes were worse following late evenings. There was a strong family history of somnambulance in the parent’s siblings. They denied any sleep disordered breathing symptoms. Parents were reassured and educated about parasomnia's self-limited nature but to keep a safe environment and avoid sleep deprivation. Conclusion The majority of parasomnia in children have benign outcomes and eventual self-resolution with age. However, rare circumstances arise where these events can be hazardous including sleep-cooking, risking fire and burns or, as in this case, unknowingly walking into traffic. A sleep study is not always needed as parasomnias are a clinical diagnosis. However, it’s important to note that if a patient has a history of parasomnias parents should be educated on the importance of keeping a safe environment to prevent possible harm. Support (if any)

1045 Resolution of Sexsomnia with Positive Airway Pressure

Abstract Introduction Sexsomnia is an infrequently encountered non-rapid eye movement (NREM) arousal disorder that can overlap with obstructive sleep apnea (OSA). Treatment of underlying OSA has been reported to resolve sexsomnia episodes. Report of case(s) A 26-year-old overweight man was referred to our Sleep Disorders Center for evaluation of possible “REM sleep behavior disorder.” The patient’s wife reported that he would fondle her breasts while he slept. Episodes began 6 months prior to his referral and occurred once every 1-2 months. During episodes, the patient did not get out of bed. He did not recall the events and denied dream recall. The patient had an infant at home with resultant sleep deprivation. He slept between 5-7 hours a night and stated episodes were more common with decreased total sleep time. Additionally, he reported recent increase in stressors after moving in with his in-laws. On evaluation, patient endorsed bruxism for which he wore a mouth guard. He reported history of sleepwalking in elementary school. He denied excessive daytime sleepiness, snoring, witnessed apneas, gasping arousals, morning headaches, unrefreshing sleep, insomnia, or substance use. He was advised to increase total sleep time and pursue a baseline polysomnogram to evaluate for sleep-disordered breathing. The polysomnogram demonstrated moderate OSA (apnea/hypopnea index of 17). Excessive arousals out of N3 sleep were not reported. He was initiated on auto-titrating positive airway pressure (APAP) and maintained moderate adherence for 2 months. At his follow-up visit, he reported no further episodes of nocturnal fondling after PAP initiation despite persistent sleep deprivation and home stressors. Conclusion This case highlights the importance of screening for sleep-disordered breathing which can coexist with NREM parasomnias such as sexsomnia. Even in patients without clear symptoms of sleep-disordered breathing, the evaluation, diagnosis, and treatment of possible OSA could decrease the frequency of sexsomnia episodes. Although this case study was mainly limited by short follow-up duration, the patient’s resolution of sexsomnia in that time demonstrates the importance of treatment of concurrent sleep-related breathing disorders. Support (if any) None.

Group Cognitive Behavioural Therapy for Non-Rapid Eye Movement Parasomnias: Long-Term Outcomes and Impact of COVID-19 Lockdown

Prior to the COVID-19 pandemic, we demonstrated the efficacy of a novel Cognitive Behavioural Therapy programme for the treatment of Non-Rapid Eye Movement Parasomnias (CBT-NREMP) in reducing NREM parasomnia events, insomnia and associated mood severities. Given the increased prevalence and worsening of sleep and affective disorders during the pandemic, we examined the sustainability of CBT-NREMP following the U.K.'s longest COVID-19 lockdown (6 January 2021-19 July 2021) by repeating the investigations via a mail survey in the same 46 patient cohort, of which 12 responded. The survey included validated clinical questionnaires relating to NREM parasomnia (Paris Arousal Disorder Severity Scale), insomnia (Insomnia Severity Index) and anxiety and depression (Hospital Anxiety and Depression Scale). Patients also completed a targeted questionnaire (i.e., Impact of COVID-19 Lockdown Questionnaire, ICLQ) to assess the impact of COVID-19 lockdown on NREM parasomnia severity, mental health, general well-being and lifestyle. Clinical measures of NREM parasomnia, insomnia, anxiety and depression remained stable, with no significant changes demonstrated in questionnaire scores by comparison to the previous investigatory period prior to the COVID-19 pandemic: p (ISI) = 1.0; p (HADS) = 0.816; p (PADSS) = 0.194. These findings support the longitudinal effectiveness of CBT-NREMP for up to three years following the clinical intervention, and despite of the COVID-19 pandemic.

A case-control study of sexualised behaviour in sleep: A strong association with psychiatric comorbidity and relationship difficulties

Sexualised behaviour in sleep (SBS) is a relatively rare parasomnia consisting of instinctive behaviours of a sexual nature occurring during non-rapid-eye movement (NREM) sleep. Little information exists at present regarding the clinical features and onset of this condition as well as its link to psychiatric comorbidity, other sleep disorders and history of adverse early life experience. Aims were to typify the condition further and compare features of SBS patients to those with other NREM parasomnias. MethodsDetails of 335 consecutive patients presenting to a single tertiary sleep centre with non-rapid eye movement (NREM)-parasomnias over a 15-year period (2005–2020) were examined. Data were collated by reviewing case-notes for anthropometric data, past medical history, clinical findings, and video polysomnography. SBS patients were compared to a cohort of 270 non-SBS, NREM-sleep disorder patients (case-control) to ascertain whether they had any distinguishing features from other parasomnias classified in this group. ResultsSixty-five patients with SBS were identified: 58 males, 7 females (comprising 19.4% of the cohort overall). Mean age at presentation was 33(±9.5) years. Onset of behaviours was commoner in adulthood in the SBS cohort, whereas non-SBS, NREM-parasomnia onset (n = 270) was commoner in childhood: 61.1% and 52.9% respectively (p = 0.007). An association was identified between the presence of psychiatric diagnoses and onset of SBS (p = 0.028). Significant triggers for SBS behaviours included alcohol consumption (p < 0.001), intimate relationship difficulties (p = 0.009) and sleep deprivation (p = 0.028). Patients with SBS were significantly more likely to report sleepwalking as an additional NREM behaviour (p < 0.001). Males were more likely to present at clinic together with their bedpartner and females presented alone. A history of SBS appeared to be more common in those working in the armed forces or the police compared to those presenting with non-SBS, NREM-parasomnias (p = 0.004). ConclusionsSBS is more common in clinical practice than previously described and presents with some distinguishing features within the NREM disorder category. This study is the first to identify that onset in childhood or lack of amnesia does not preclude the condition and that patterns of presentation differ between men and women. Sleepwalkers particularly should be asked about SBS. Comorbid psychiatric conditions, profession and intimate partner difficulties are strong determinants of the presentation.

Non-REM parasomnias: a scoping review of dreams and dreamlike mentation

To establish patterns or themes of dreams and dreamlike mentation content reported in all forms of non-rapid eye movement (NREM) parasomnias and to identify gaps in the current understanding of this topic. A scoping review of available evidence on dreams and dreamlike mentation in NREM parasomnias was conducted in accordance with the PRISMA-ScR guidelines. We searched peer-reviewed literature using Google Scholar, PubMed, Ovid (Embase), Ovid Medline®, Global Health, and APA Psych Info. The Mixed Method Appraisal Tool (MMAT) was used to appraise the quality of selected articles. The final analysis included 16 studies. All of the studies were from high-income countries. The studies reported on dreams and dreamlike mentation in NREM parasomnias, but there was scarcity of literature for sexsomnia, sleep-related eating disorder, and confusional arousal. All of the studies had the highest quality as shown by the MMAT (76%-100%). Emotions such as apprehension and misfortune were associated with sleepwalking and sleep terrors. Sleep studies involving collection of dream content immediately following NREM parasomnia could significantly minimize reporting bias and improve dream data quality.

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

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 &lt; 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 &lt; 0.001). 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.

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.

What respiratory physicians should know about parasomnias.

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.

Parasomnias during trans-meridian and long-distance travel: Critical literature review and clinical practice recommendations.

Parasomnias are undesirable events that occur during sleep. They can be classified into rapid eye movement parasomnias and non-rapid eye movement parasomnias. Those who experience parasomnias may be anxious about travel for many reasons, including the occurrence of unwanted events during the trip, increased exposure to environmental trigger factors, and the propensity for harm to occur due to unfamiliar surroundings while travelling. There is a paucity of literature examining this area. This review summarizes the relevant literature and the clinical experience of the authors to compile clinical practice recommendations. The clinical features of parasomnias and how they relate to trans-meridian and long-distance travel are described. Triggers for non-rapid eye movement parasomnias, particularly the use of sedative hypnotic drugs, alcohol, drug withdrawal, sleep deprivation, emotional stress and environmental stimulations, are described. Management of parasomnias whilst travelling is reviewed, with a particular focus on trigger minimalization. The role for clonazepam and melatonin is outlined. At the pre-travel health consultation, the physician is strongly advised to screen the traveller for co-morbid sleep conditions, which exacerbate parasomnias. Areas for further research are explored, including the extent to which these sleep disorders impact on the travel experience.

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

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). 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. 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. 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.

Medicolegal aspects of non-rapid eye movement parasomnias

In a subset of adults with non-rapid eye movement (NREM) parasomnias, clinical variants might be violent in nature and can potentially result in unintentional but considerable harm. As such, there is substantial interest on the forensic ramifications of these sleep behaviours. This review examined the diagnostic criteria for parasomnias established in the context of international classification systems; medicolegal case reports; legal frameworks; and court cases in and outside of Singapore, to provide an overview of the implications of NREM parasomnias. Violent or injurious behaviours that occurred in the context of somnambulism, otherwise known as sleepwalking, have challenged traditional legal theories of criminal culpability. Yet little has changed in the application of sleep science to criminal responsibility. In Singapore, the defence of somnambulism has hitherto not been directly raised. Nonetheless, sleep medicine practitioners may increasingly be requested to render their opinions on legal issues pertaining to violent or injurious behaviours allegedly arising during sleep. Although the understanding of NREM parasomnias has improved, there is still a dearth of evidence to support both medical and legal decisions in this area. NREM parasomnias come with disquieting legal and forensic implications for adjudicating criminal responsibility. There is a need to critically examine legal perspectives on behaviours occurring during sleep. More reliable empirical studies investigating the pathophysiology of NREM parasomnias can offer clearer diagnostic guidelines and address complex behaviours of NREM that often come with medicolegal implications.

Sleep Disturbances During Shift Work

Around 21% of workers reported working on shifts in 2017, and consequently, shift workers experience multiple sleep disturbances such as excessive sleepiness, insomnia, sleep deprivation, and social jet lag. These eventually lead to shift work disorder or exacerbation of other sleep disorders such as insomnia, obstructive sleep apnea, restless legs syndrome, and nonrapid eye movement parasomnia. Despite multiple interventions and guidelines, poor compliance to treatment is often encountered due to temporary relief of sleep disturbances provided by the treatment. Hence there is a need for comprehensive evaluation of those individuals who need to be awake during the night and asleep during the day.

Nocturnal frontal lobe epilepsy presenting as sleepwalking episodes and restless leg syndrome-like symptoms

Nocturnal frontal lobe epilepsy (NFLE) is characterized by seizures with complex motor behaviors arising mainly during sleep. Varied clinical presentations and nonspecific electroencephalogram findings make it difficult to distinguish NFLE from other nocturnal paroxysmal events such as nonrapid eye movement (NREM) parasomnias and restless leg syndrome (RLS). Here, we present a case of NFLE, which had a complex clinical presentation resembling features suggestive of RLS and NREM parasomnia and posed a diagnostic challenge. Initiation of carbamazepine as the anti-epileptic led to rapid resolution of symptoms.

Validation of the Dutch translation of the Paris Arousal Disorders Severity Scale for non-REM parasomnias in a 1-year and 1-month version.

We created a Dutch version of the Paris Arousal Disorders Severity Scale (PADSS), which assesses non-rapid eye movement (NREM) parasomnia symptoms over the past year (PADSS-year). This questionnaire was previously validated in patients with sleep walking and/or sleep terrors (SW/ST). We validated the questionnaire in SW/ST patients, and in a broader population, including patients with confusional arousals, comorbidities, and medication users ("other NREM parasomnias"). Furthermore, we introduced a version covering the past month (PADSS-month), with the potential purpose of evaluating symptom evolution and treatment response. We compared PADSS scores among 54 SW/ST patients, 34 age-matched controls, and 23 patients with other NREM parasomnias. We evaluated discriminative capacity, internal consistency, and construct validity. Furthermore, we assessed the test-retest reliability and treatment response of PADSS-month. Healthy controls scored significantly lower than both patient groups. We found an excellent diagnostic accuracy (area under the curve PADSS-year 0.990, PADSS-month 0.987) and an acceptable internal consistency. Exploratory factor analysis identified 3 components: "behaviors outside the bed," "behaviors in/around the bed," and "violent behaviors," with the former 2 factors reflecting the distinction between SW and ST. PADSS-month showed an acceptable test-retest reliability (0.75). Additionally, PADSS-month significantly decreased after pharmaceutical and/or behavioral treatment. This change was correlated with the clinical impression of the caregiver, implying that PADSS-month is sensitive to treatment effects. The Dutch PADSS questionnaire can be used as a screening tool in a broad population of patients with NREM parasomnia, not only SW/ST. Furthermore, we validated a PADSS-month version to assess the evolution of symptoms and treatment effect. van Mierlo P, Hermans L, Arnulf I, Pijpers A, Overeem S, van Gilst M. Validation of the Dutch translation of the Paris Arousal Disorders Severity Scale for non-REM parasomnias in a 1-year and 1-month version. J Clin Sleep Med. 2022;18(4):1135-1143.

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.