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Study Objectives: To investigate amplitude and phase of the circadian rhythm of core body temperature (CBT) via the continuous measure of the gastrointestinal temperature in participants with idiopathic hypersomnia (IH), non-specified hypersomnia (NSH) compared to healthy controls (HC) in a constant routine standardized bedrest (BR) protocol., Methods: Consecutive participants evaluated in a National Reference Center for Rare Hypersomnias benefited from an extensive evaluation with one night polysomnography, followed by modified Multiple Sleep Latency Test (mMSLT), and a continuous 32-hour BR recording in standardized conditions. CBT was recorded via a telemetry pill (e-Celsius®) during the BR, modeled by a Cosinor, with extraction of MESOR, amplitude and phase. Participants with IH, diagnosed according to ICSD-3, were compared with participants with NSH (complaint of hypersomnolence but normal mMSLT and BR), and HC. Participants were divided in 4 groups based on their mMSLT mean sleep latency (mMSLT+,≤8min) and their BR total sleep time (BR+,≥19h)., Results: 108 participants (80% women, 28.3±7.8 y.o) were included in the analyses, 81 IH (83% women), 16 NSH (75% women), 11 HC (64% women). Cosinor amplitude and phase of CBT did not differ between IH, NSH and HC, nor in the subgroup analysis (37 BR+/mMSLT+, 35 BR+/mMSLT-, 9 BR-/mMSLT+, 27 BR-/mMSLT-). No difference in chronotypes was observed between groups. Women had a greater MESOR and reduced CBT amplitude compared to men., Conclusion: The circadian rhythm of CBT showed no difference in amplitude or phase between IH, NSH and HC, and was not related to prolonged sleep time or objective daytime sleepiness., (© The Author(s) 2024. Published by Oxford University Press on behalf of Sleep Research Society. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

The aim of the present study was to examine gender and age-specific effects on subjective daytime sleepiness (as measured by the Epworth Sleepiness Scale), body weight and eating behaviour in patients with central disorders of hypersomnolence. Based on the European Narcolepsy Network database, we compared 1035 patients with narcolepsy type I and 505 patients with other central disorders of hypersomnolence ("narcoleptic borderland"), including narcolepsy type II (N = 308) and idiopathic hypersomnia (N = 174), using logistic regression and general linear models. In the entire study population, the Epworth Sleepiness Scale was higher in women (N = 735, mean age = 30 years, mean Epworth Sleepiness Scale = 16.6 ± SD 3.9) than in men (N = 805, mean age = 32 years, mean Epworth Sleepiness Scale = 15.8 ± SD 4.4). In women with narcolepsy type I (N = 475), both Epworth Sleepiness Scale and body mass index increased in parallel with age. In women of the narcoleptic borderland (N = 260), the Epworth Sleepiness Scale markedly peaked in their early 30s, while body mass index only started to rise at that age. This rise in body mass index following the Epworth Sleepiness Scale peak cannot be explained by sleepiness-induced uncontrolled eating, as self-reported uncontrolled eating was negatively associated with the Epworth Sleepiness Scale in this group. We propose that the narcoleptic borderland harbours a unique cluster of women in their fertile years with an unexplored aetiology requiring further investigation towards tailored interventions., (© 2024 The Author(s). Journal of Sleep Research published by John Wiley & Sons Ltd on behalf of European Sleep Research Society.)

Narcolepsy is a rare lifelong sleep disorder characterized by excessive daytime sleepiness with variable expression of cataplexy, sleep paralysis, sleep-related hallucinations and disrupted nocturnal sleep. Affected individuals also experience additional impairing symptoms, including (but not limited to) difficulties with attention, memory and concentration, brain fog, mood instability and fatigue, with a substantial impact on everyday life. Diagnostic delays of up to 10 years are common, primarily due to the substantial heterogeneity in clinical presentation of narcolepsy symptoms and presence of significant comorbidities. The disconnect in language used by clinicians and patients could be a factor contributing to diagnostic delays, but it has not been much studied. We followed a two-part approach to investigate the impact of this possible mismatch in language use. Firstly, a comprehensive literature search was conducted to identify publications reporting discrepancies in language relating to narcolepsy symptoms used by clinicians and patients. As a gap in the literature was anticipated, we supplemented the search results with practical strategies based on our clinical experience to facilitate dialog between clinicians and people living with narcolepsy, as well as proposing future research ideas. The findings of the narrative review, complemented by expert clinical opinion, are intended to help clinicians recognize narcolepsy symptoms and to refer patients with suspected narcolepsy, when appropriate. Although it is unknown to what extent a disconnect in language may contribute to diagnostic delays, we hope that better recognition of the varied clinical presentations of narcolepsy will lead to timelier diagnosis and help improve patient outcomes., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: All authors report article publishing charges and writing assistance for this article were provided by Takeda Pharmaceutical Company Limited. Lucie Barateau reports a relationship with Bioproject that includes: board membership and travel reimbursement. Lucie Barateau reports a relationship with Idorsia that includes: board membership and travel reimbursement. Lucie Barateau reports a relationship with Jazz Pharmaceuticals that includes: board membership. Lucie Barateau reports a relationship with Takeda that includes: board membership. Anne Marie Morse reports a relationship with Alkermes that includes: board membership, consulting or advisory, and speaking and lecture fees. Anne Marie Morse reports a relationship with Avadel Pharmaceuticals that includes: board membership, consulting or advisory, and speaking and lecture fees. Anne Marie Morse reports a relationship with Eisai Co Ltd that includes: board membership, consulting or advisory, and speaking and lecture fees. Anne Marie Morse reports a relationship with Harmony Biosciences that includes: board membership, consulting or advisory, and speaking and lecture fees. Anne Marie Morse reports a relationship with Jazz Phamaceuticals that includes: board membership, consulting or advisory, funding grants, and speaking and lecture fees. Anne Marie Morse reports a relationship with NLS Phamaceutics that includes: board membership, consulting or advisory, and speaking and lecture fees. Anne Marie Morse reports a relationship with Takeda that includes: board membership, consulting or advisory, and speaking and lecture fees. Anne Marie Morse reports a relationship with Coverys Community Healthcare Foundation that includes: funding grants. Anne Marie Morse reports a relationship with Geisinger Health Plan that includes: funding grants. Anne Marie Morse reports a relationship with National Institutes of Health that includes: funding grants. Anne Marie Morse reports a relationship with ResMed Foundation that includes: funding grants. Anne Marie Morse reports a relationship with UCB Pharmaceuticals that includes: funding grants. Anne Marie Morse reports a relationship with Neura Health that includes: advisor. Anne Marie Morse reports a relationship with DAMM Good Sleep, LLC, that includes: employment. Simerpal K. Gill reports a relationship with Takeda that includes: employment and equity or stocks. Fabio Pizza reports a relationship with Takeda that includes: board membership. Fabio Pizza reports a relationship with Bioproject that includes: speaking and lecture fees and travel reimbursement. Fabio Pizza reports a relationship with Jazz Pharmaceuticals that includes: speaking and lecture fees. Chad Ruoff reports a relationship with Alkermes that includes: board membership, advisory. Chad Ruoff reports a relationship with Eisai Co Ltd that includes: board membership, advisory. Chad Ruoff reports a relationship with Jazz Pharmaceuticals that includes: board membership, advisory and funding grants. Chad Ruoff reports a relationship with Takeda that includes: board membership, advisory., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

We aim to identify genetic markers associated with idiopathic hypersomnia, a disabling orphan central nervous system disorder of hypersomnolence that is still poorly understood. In our study, DNA was extracted from 79 unrelated patients diagnosed with idiopathic hypersomnia with long sleep time at the National Reference Center for Narcolepsy-France according to very stringent diagnostic criteria. Whole exome sequencing on the first 30 patients with idiopathic hypersomnia (25 females and 5 males) allowed the single nucleotide variants to be compared with a control population of 574 healthy subjects from the French Exome project database. We focused on the identification of genetic variants among 182 genes related to the regulation of sleep and circadian rhythm. Candidate variants obtained by exome sequencing analysis were then validated in a second sample of 49 patients with idiopathic hypersomnia (37 females and 12 males). Our study characterised seven variants from six genes significantly associated with idiopathic hypersomnia compared with controls. A targeted sequencing analysis of these seven variants on 49 other patients with idiopathic hypersomnia confirmed the relative over-representation of the A➔C variant of rs2859390, located in a potential splicing-site of PER3 gene. Our findings support a genetic predisposition and identify pathways involved in the pathogeny of idiopathic hypersomnia. A variant of the PER3 gene may predispose to idiopathic hypersomnia with long sleep time., (© 2024 European Sleep Research Society.)

Since the first description of narcolepsy at the end of the 19th Century, great progress has been made. The disease is nowadays distinguished as narcolepsy type 1 and type 2. In the 1960s, the discovery of rapid eye movement sleep at sleep onset led to improved understanding of core sleep-related disease symptoms of the disease (excessive daytime sleepiness with early occurrence of rapid eye movement sleep, sleep-related hallucinations, sleep paralysis, rapid eye movement parasomnia), as possible dysregulation of rapid eye movement sleep, and cataplexy resembling an intrusion of rapid eye movement atonia during wake. The relevance of non-sleep-related symptoms, such as obesity, precocious puberty, psychiatric and cardiovascular morbidities, has subsequently been recognized. The diagnostic tools have been improved, but sleep-onset rapid eye movement periods on polysomnography and Multiple Sleep Latency Test remain key criteria. The pathogenic mechanisms of narcolepsy type 1 have been partly elucidated after the discovery of strong HLA class II association and orexin/hypocretin deficiency, a neurotransmitter that is involved in altered rapid eye movement sleep regulation. Conversely, the causes of narcolepsy type 2, where cataplexy and orexin deficiency are absent, remain unknown. Symptomatic medications to treat patients with narcolepsy have been developed, and management has been codified with guidelines, until the recent promising orexin-receptor agonists. The present review retraces the steps of the research on narcolepsy that linked the features of the disease with rapid eye movement sleep abnormality, and those that do not appear associated with rapid eye movement sleep., (© 2024 The Author(s). Journal of Sleep Research published by John Wiley & Sons Ltd on behalf of European Sleep Research Society.)

Objectives: Kleine-Levin syndrome (KLS) is a rare recurrent hypersomnolence disorder associated with cognitive and behavioral disturbances, of unknown origin, but inflammatory mechanisms could be involved. We aimed to explore in vivo microglia activation using [ 18 F]DPA-714 PET imaging in patients with KLS compared with controls, and during symptomatic vs asymptomatic periods., Methods: Patients with KLS and controls underwent a standardized clinical evaluation and PET imaging, using a radiolabeled ligand specific to the 18 kDa translocator protein. Images were processed on the PMOD (peripheral module) interface using a standard uptake value (SUV). Five regions of interest (ROIs) were analyzed: hypothalamus, thalamus, frontal area, cerebellum, and whole brain. SUV ratios (SUVr) were calculated by normalizing SUV with cerebellum uptake., Results: Images of 17 consecutive patients with KLS (7 during episodes, 10 out of episodes) and 14 controls were analyzed. We found no SUV/SUVr difference between KLS and controls, between patients in and out episodes in all ROIs, and no correlation between SUVr and episode duration at the time of PET scan. No association was found between SUVr and sex, disease duration, or orexin levels., Discussion: Our findings do not support the presence of neuroinflammation in KLS. Further research is needed to identify relevant biomarkers in KLS.

Narcolepsy is a rare cause of hypersomnolence and may be associated or not with cataplexy, i.e. sudden muscle weakness. These forms are designated narcolepsy-type 1 (NT1) and -type 2 (NT2), respectively. Notable characteristics of narcolepsy are that most patients carry the HLA-DQB1*06:02 allele and NT1-patients have strongly decreased levels of hypocretin-1 (synonym orexin-A) in the cerebrospinal fluid (CSF). The pathogenesis of narcolepsy is still not completely understood but the strong HLA-bias and increased frequencies of CD4 + T cells reactive to hypocretin in the peripheral blood suggest autoimmune processes in the hypothalamus. Here we analyzed the transcriptomes of CSF-cells from twelve NT1 and two NT2 patients by single cell RNAseq (scRNAseq). As controls, we used CSF cells from patients with multiple sclerosis, radiologically isolated syndrome, and idiopathic intracranial hypertension. From 27,255 CSF cells, we identified 20 clusters of different cell types and found significant differences in three CD4 + T cell and one monocyte clusters between narcolepsy and multiple sclerosis patients. Over 1000 genes were differentially regulated between patients with NT1 and other diseases. Surprisingly, the most strongly upregulated genes in narcolepsy patients as compared to controls were coding for the genome-encoded MTRNR2L12 and MTRNR2L8 peptides, which are homologous to the mitochondria-encoded HUMANIN peptide that is known playing a role in other neurological diseases including Alzheimer's disease., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Study Objectives: Narcolepsy type 2 (NT2) is an understudied central disorder of hypersomnolence sharing some similarities with narcolepsy type 1 and idiopathic hypersomnia (IH). We aimed: (1) to assess systematically the symptoms in patients with NT2, with self-reported questionnaires: Epworth Sleepiness Scale (ESS), Narcolepsy Severity Scale (NSS), IH Severity Scale (IHSS), and (2) to evaluate the responsiveness of these scales to treatment., Methods: One hundred and nine patients with NT2 (31.4 ± 12.2 years old, 47 untreated) diagnosed according to ICSD-3 were selected in a Reference Center for Narcolepsy. They all completed the ESS, subgroups completed the modified NSS (NSS-2, without cataplexy items) (n = 95) and IHSS (n = 76). Some patients completed the scales twice (before/during treatment): 42 ESS, 26 NSS-2, and 30 IHSS., Results: Based on NSS-2, all untreated patients had sleepiness, 58% disrupted nocturnal sleep, 40% hallucinations, and 28% sleep paralysis. On IHSS, 76% reported a prolonged nocturnal sleep, and 83% sleep inertia. In the independent sample, ESS and NSS-2 scores were lower in treated patients, with same trend for IHSS scores. After treatment, ESS, NSS-2, and IHSS total scores were lower, with a mean difference of 3.7 ± 4.1, 5.3 ± 6.7, and 4.1 ± 6.2, respectively. The minimum clinically important difference between untreated and treated patients were 2.1 for ESS, 3.3 for NSS-2, and 3.1 for IHSS. After treatment, 61.9% of patients decreased their ESS > 2 points, 61.5% their NSS-2 > 3 points, and 53.3% their IHSS > 3 points., Conclusions: NSS-2 and IHSS correctly quantified symptoms' severity and consequences in NT2, with good performances to objectify response to medications. These tools are useful for monitoring and optimizing NT2 management, and for use in clinical trials., (© The Author(s) 2024. Published by Oxford University Press on behalf of Sleep Research Society. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Background and Objectives: Narcolepsy type 1 (NT1) is due to the loss of hypothalamic neurons that produce orexin (ORX), by a suspected immune-mediated process. Rare postmortem studies are available and failed to detect any inflammation in the hypothalamic region, but these brains were collected years after the first symptoms. In vivo studies close to disease onset are lacking. We aimed to explore microglia density in the hypothalamus and thalamus in NT1 compared with controls using [ 18 F]DPA-714 PET and to study in NT1 the relationships between microglia density in the hypothalamus and in other regions of interest (ROIs) with disease duration, severity, and ORX levels., Methods: Patients with NT1 and controls underwent a standardized clinical evaluation and [ 18 F]DPA-714 PET imaging using a radiolabeled ligand specific to the 18 kDa translocator protein (TSPO). TSPO genotyping determined receptor affinity. Images were processed on peripheral module interface using standard uptake value (SUV) on ROIs: hypothalamus, thalamus, frontal area, cerebellum, and the whole brain. SUV ratios (SUVr) were calculated by normalizing SUV with cerebellum uptake., Results: A total of 41 patients with NT1 (21 adults, 20 children, 10 with recent disease onset <1 year) and 35 controls were included, with no significant difference between groups for [ 18 F]DPA-714 binding (SUV/SUVr) in the hypothalamus and thalamus. Unexpectedly, significantly lower SUVr in the whole brain was found in NT1 compared with controls (0.97 ± 0.06 vs 1.08 ± 0.22, p = 0.04). The same finding between NT1 and controls in the whole brain was observed in those with high or mixed TSPO affinity ( p = 0.03 and p = 0.04). Similar trend was observed in the frontal area in NT1 (0.96 ± 0.09 vs 1.09 ± 0.25, p = 0.05). In NT1, no association was found between SUVr in different ROIs and age, disease duration, severity, or ORX levels., Discussion: We found no evidence of in vivo increased microglia density in NT1 compared with controls, even close to disease onset, and even unexpectedly a decrease in the whole brain of these patients. These findings do not support the presence of neuroinflammation in the destruction process of ORX neurons., Trial Registration Information: ClinicalTrials.org NCT03754348.

The differential diagnosis of narcolepsy type 1, a rare, chronic, central disorder of hypersomnolence, is challenging due to overlapping symptoms with other hypersomnolence disorders. While recent years have seen significant growth in our understanding of nocturnal polysomnography narcolepsy type 1 features, there remains a need for improving methods to differentiate narcolepsy type 1 nighttime sleep features from those of individuals without narcolepsy type 1. We aimed to develop a machine learning framework for identifying sleep features to discriminate narcolepsy type 1 from clinical controls, narcolepsy type 2 and idiopathic hypersomnia. The population included polysomnography data from 350 drug-free individuals (114 narcolepsy type 1, 90 narcolepsy type 2, 105 idiopathic hypersomnia, and 41 clinical controls) collected at the National Reference Centers for Narcolepsy in Montpelier, France. Several sets of nocturnal sleep features were explored, as well as the value of time-resolving sleep architecture by analysing sleep per quarter-night. Several patterns of nighttime sleep evolution emerged that differed between narcolepsy type 1, clinical controls, narcolepsy type 2 and idiopathic hypersomnia, with increased nighttime instability observed in patients with narcolepsy type 1. Using machine learning models, we identified rapid eye movement sleep onset as the best single polysomnography feature to distinguish narcolepsy type 1 from controls, narcolepsy type 2 and idiopathic hypersomnia. By combining multiple feature sets capturing different aspects of sleep across quarter-night periods, we were able to further improve between-group discrimination and could identify the most discriminative sleep features. Our results highlight salient polysomnography features and the relevance of assessing their time-dependent changes during sleep that could aid diagnosis and measure the impact of novel therapeutics in future clinical trials., (© 2024 European Sleep Research Society.)

Excessive daytime sleepiness (EDS) is frequent among patients with obstructive sleep apnea hypopnea syndrome (OSAHS) and can persist despite the optimal correction of respiratory events (apnea, hypopnea and respiratory efforts), using continuous positive airway pressure (CPAP) or mandibular advancement device. Symptoms like apathy and fatigue may be mistaken for EDS. In addition, EDS has multi-factorial origin, which makes its evaluation complex. The marketing authorization [Autorisation de Mise sur le Marché (AMM)] for two wake-promoting agents (solriamfetol and pitolisant) raises several practical issues for clinicians. This consensus paper presents recommendations of good clinical practice to identify and evaluate EDS in this context, and to manage and follow-up the patients. It was conducted under the mandate of the French Societies for sleep medicine and for pneumology [Société Française de Recherche et de Médecine du Sommeil (SFRMS) and Société de Pneumologie de Langue Française (SPLF)]. A management algorithm is suggested, as well as a list of conditions during which the patient should be referred to a sleep center or a sleep specialist. The benefit/risk balance of a wake-promoting drug in residual EDS in OSAHS patients must be regularly reevaluated, especially in elderly patients with increased cardiovascular and psychiatric disorders risks. This consensus is based on the scientific knowledge at the time of the publication and may be revised according to their evolution., Competing Interests: Declaration of competing interest Pr Andrejak has been a speaker at symposiums for Moderna, Chiesi, AstraZeneca et Insmed, unrelated to this subject. Pr Arnulf was a paid consultant for Idorsia Pharma in 2020 and unpaid for Takeda Pharma in 2022, unrelated to this subject. Dr Baillieul has been paid for work for Jazz Pharmaceuticals; clinical study investigator for Bioprojet; received support from Agiradom, Vitalaire and Bioprojet for participation in a congress. Dr Barateau was a consultant for Bioprojet, Takeda, Idorsia, and Jazz Pharmaceuticals between 2020 and 2022, and a speaker for Bioprojet, Jazz Pharmaceuticals and Idorsia. Dr Bequignon has been a consultant for Air Liquide Santé, GSK, Sanofi, paid talks for Bioprojet, Inspire, GSK, Sanofi, Amplifon. Pr Boutouyrie was a consultant for Bioprojet and Jazz-pharmaceutics in 2021 and 2022, related to this subject. Pr Dauvilliers has been consultant and speaker and has been invited to conferences by UCB Pharma, Jazz, Theranexus, Idorsia, Takeda, Avadel and Bioprojet. Pr Gagnadoux has worked as consultant for Air Liquide Santé, Asten santé, Bioprojet, Inspire, Sefam, Resmed; and as a paid speaker for Bioprojet, Cidelec, Inspire, Jazz Pharmaceuticals, Philips Respironics. Pr Geoffroy has been paid speaker for Biocodex, Bioprojet, Idorsia, Janssen-Cilag, Jazz pharmaceuticals, Lundbeck, MySom- meil, Withings; received fees as expert for Apneal, Biocodex, Dayvia, Idorsia, Janssen-Cilag, Jazz pharmaceuti- cals, Myndblue, Posos, ResilEyes, Withings; and is a member of the advisory boards of: Apneal, Idorsia, Mindblue, Mysommeil. Dr Jaffuel has been involved in clinical trials, scientific work, consulting, conferences, symposiums and other activities over the past 5 years for the following companies and organizations: ALK, AstraZeneca, Bohringer Ingelheim, Chiesi, GlaxoSmithKline, Novartis, Sanofi; en rapport avec l'article, Adene, Bastide, Bioprojet, Jazz, Löwenstein, LVL, Nomics, Philips Respironics, Resmed, Sefam, Tali. Pr Micoulaud-Franchi has been a consultant for Gilead, Eisai et Bioprojet. Pr Monaca has been speaker for UCB Pharma, Jazz; consultant for Resmed, investigator for Jazz, Bioprojet, Theranexus. Pr Montani and Dr report no conflicts of interest. Dr Patout: research project funding: Fisher & Paykel, Resmed, Asten Santé - Consultant: Resmed, Philips Respironics, Asten Santé, GSK - Paid talks: Philips Respironics, Resmed, Elivie, SOS O2, Chiesi, Asten Santé, Air Liquide Medical Système, Antadir, Jazz Pharmaceutical, Lowenstein - Actions: Kernel Biomedical - Conference support: Asten Santé. Pr Pépin has received research funding from: Air Liquide Foundation, Agiradom, AstraZeneca, Fisher and Paykel, Mutualia, Philips, Resmed and Vitalaire; et a été consultant pour Agiradom, AstraZeneca, Boehringer Ingelheim, Jazz pharmaceutical, Night Balance, Philips, Resmed et Sefam. Pr Philip reports that he has been a consultant for Jazz Phar maceuticals and Bioprojet. Pr Tamisier has received payment for scientific communication from Resmed, Philips, Elivie and Agiradom, support for participating in a congress for Laboratoires Agiradom. RT received financing for research from Fondations Resmed APMC, Resmed, Philips, and Vitalaire, took part in scientific committees for Respicardia, Sorin et Jazz Pharmaceutical, Inspire and Resmed. Pr Trzepizur was invited to scientific congress by Asten and gave a paid talk for AstraZeneca., (Copyright © 2024 SPLF and Elsevier Masson SAS. All rights reserved.)

The mechanisms underlying the individual need for sleep are unclear. Sleep duration is indeed influenced by multiple factors, such as genetic background, circadian and homeostatic processes, environmental factors, and sometimes transient disturbances such as infections. In some cases, the need for sleep dramatically and chronically increases, inducing a daily-life disability. This "excessive need for sleep" (ENS) was recently proposed and defined in a European Position Paper as a dimension of the hypersomnolence spectrum, "hypersomnia" being the objectified complaint of ENS. The most severe form of ENS has been described in Idiopathic Hypersomnia, a rare neurological disorder, but this disabling symptom can be also found in other hypersomnolence conditions. Because ENS has been defined recently, it remains a symptom poorly investigated and understood. However, protocols of long-term polysomnography recordings have been reported by expert centers in the last decades and open the way to a better understanding of ENS through a neurophysiological approach. In this narrative review, we will 1) present data related to the physiological and pathological variability of sleep duration and their mechanisms, 2) describe the published long-term polysomnography recording protocols, and 3) describe current neurophysiological tools to study sleep microstructure and discuss perspectives for a better understanding of ENS., Competing Interests: Declaration of competing interest The authors report no financial or non-financial conflicts of interest in this work., (Copyright © 2024 Elsevier Masson SAS. All rights reserved.)

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., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Sleep disturbances after ischaemic stroke include alterations of sleep architecture, obstructive sleep apnea, restless legs syndrome, daytime sleepiness and insomnia. Our aim was to explore their impacts on functional outcomes at month 3 after stroke, and to assess the benefit of continuous positive airway pressure in patients with severe obstructive sleep apnea. Ninety patients with supra-tentorial ischaemic stroke underwent clinical screening for sleep disorders and polysomnography at day 15 ± 4 after stroke in a multisite study. Patients with severe obstructive apnea (apnea-hypopnea index ≥ 30 per hr) were randomized into two groups: continuous positive airway pressure-treated and sham (1:1 ratio). Functional independence was assessed with the Barthel Index at month 3 after stroke in function of apnea-hypopnea index severity and treatment group. Secondary objectives were disability (modified Rankin score) and National Institute of Health Stroke Scale according to apnea-hypopnea index. Sixty-one patients (71.8 years, 42.6% men) completed the study: 51 (83.6%) had obstructive apnea (21.3% severe apnea), 10 (16.7%) daytime sleepiness, 13 (24.1%) insomnia, 3 (5.7%) depression, and 20 (34.5%) restless legs syndrome. Barthel Index, modified Rankin score and Stroke Scale were similar at baseline and 3 months post-stroke in the different obstructive sleep apnea groups. Changes at 3 months in those three scores were similar in continuous positive airway pressure versus sham-continuous positive airway pressure patients. In patients with worse clinical outcomes at month 3, mean nocturnal oxygen saturation was lower whereas there was no association with apnea-hypopnea index. Poorer outcomes at 3 months were also associated with insomnia, restless legs syndrome, depressive symptoms, and decreased total sleep time and rapid eye movement sleep., (© 2023 The Authors. Journal of Sleep Research published by John Wiley & Sons Ltd on behalf of European Sleep Research Society.)

Competing Interests: L. Barateau déclare avoir participé à des interventions ponctuelles pour les entreprises Bioprojet, Idorsia, Jazz Pharma, Takeda ; et avoir été prise en charge, à l’occasion de déplacements pour congrès, par Bioprojet, Idorsia, Jazz Pharmaceuticals. Y. Dauvilliers déclare avoir participé à des interventions ponctuelles pour les entreprises Bioprojet, Takeda, Avadel, Idorsia, Orexia et Jazz Pharmaceuticals. Q. Lorber déclare avoir été pris en charge, à l’occasion de déplacements pour congrès, par Vitalaire, Sos Oxygène.

Study Objectives: We report data collected from 2 reference European sleep centers on a series of patients with narcolepsy with hypocretin-1 deficiency and absence of the human leukocyte antigens (HLA) DQB1*06:02 allele., Methods: Clinical data, HLA DQ markers, and cerebrospinal fluid assessments were collected retrospectively from Caucasian patients with a diagnosis of narcolepsy type 1 with cerebrospinal fluid hypocretin-1 deficiency (< 110 pg/ml) and absence of the HLA DQB1*06:02 allele, with follow-up with at least 1 visit within the last 4 years, consecutively admitted to 2 European sleep centers (Lugano, Switzerland and Montpellier, France)., Results: Seven patients (3 of 29 patients in Lugano and 4 of 328 in Montpellier) were diagnosed with narcolepsy with hypocretin-1 deficiency and absence of HLA DQB1*06:02 (ie, 2% of patients with narcolepsy type 1). Regarding the HLA-DQB1 genotyping, 4 cases were positive for HLA DQB1*03:01, 1 for DQB1*03:02, and 3 for DQB1*02:01. Three patients had atypical cataplexy and 1 had no cataplexy. Only 2 patients had both a mean sleep latency of less than 8 minutes and more than 2 sleep onset rapid eye movement periods on the Multiple Sleep Latency Test, indicative of a less severe condition., Conclusions: Although rare, this series of 7 cases confirms that hypocretin-deficient narcolepsy should not be excluded in the absence of HLA DQB1*06:02, especially if patients are carriers of other high-risk HLA-DQB1 alleles (DQB1*03:01, *03:02, *02:01). These data support the hypothesis that narcolepsy type 1 is a wider disease spectrum linked to the loss of hypocretin peptide., Citation: Miano S, Barateau L, De Pieri M, et al. A series of 7 cases of patients with narcolepsy with hypocretin deficiency without the HLA DQB1*06:02 allele. J Clin Sleep Med . 2023;19(12):2053-2057., (© 2023 American Academy of Sleep Medicine.)

Background: Narcolepsy Type I (NT1) is a rare, life-long sleep disorder arising as a consequence of the extensive destruction of orexin-producing hypothalamic neurons. The mechanisms involved in the destruction of orexin neurons are not yet elucidated but the association of narcolepsy with environmental triggers and genetic susceptibility (strong association with the HLA, TCRs and other immunologically-relevant loci) implicates an immuno-pathological process. Several studies in animal models and on human samples have suggested that T-cells are the main pathogenic culprits., Methods: RNA sequencing was performed on four CD4 and CD8 T-cell subsets (naive, effector, effector memory and central memory) sorted by flow cytometry from peripheral blood mononuclear cells (PBMCs) of NT1 patients and HLA-matched healthy donors as well as (age- and sex-) matched individuals suffering from other sleep disorders (OSD). The RNAseq analysis was conducted by comparing the transcriptome of NT1 patients to that of healthy donors and other sleep disorder patients (collectively referred to as the non-narcolepsy controls) in order to identify NT1-specific genes and pathways., Results: We determined NT1-specific differentially expressed genes, several of which are involved in tubulin arrangement found in CD4 ( TBCB, CCT5, EML4, TPGS1, TPGS2) and CD8 ( TTLL7 ) T cell subsets, which play a role in the immune synapse formation and TCR signaling. Furthermore, we identified genes ( GZMB, LTB in CD4 T-cells and NLRP3, TRADD, IL6, CXCR1, FOXO3, FOXP3 in CD8 T-cells) and pathways involved in various aspects of inflammation and inflammatory response. More specifically, the inflammatory profile was identified in the "naive" subset of CD4 and CD8 T-cell., Conclusion: We identified NT1-specific differentially expressed genes, providing a cell-type and subset specific catalog describing their functions in T-cells as well as their potential involvement in NT1. Several genes and pathways identified are involved in the formation of the immune synapse and TCR activation as well as inflammation and the inflammatory response. An inflammatory transcriptomic profile was detected in both "naive" CD4 and CD8 T-cell subsets suggesting their possible involvement in the development or progression of the narcoleptic process., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Khajavi, Nguyen, Queriault, Chabod, Barateau, Dauvilliers, Zytnicki and Liblau.)

Sleep-wake disorders (SWD) are acknowledged risk factors for both ischemic stroke and poor cardiovascular and functional outcome after stroke. SWD are frequent following stroke, with sleep apnea (SA) being the most frequent SWD affecting more than half of stroke survivors. While sleep disturbances and SWD are frequently reported in the acute phase, they may persist in the chronic phase after an ischemic stroke. Despite the frequency and risk associated with SWD following stroke, screening for SWD remains rare in the clinical setting, due to challenges in the assessment of post-stroke SWD, uncertainty regarding the optimal timing for their diagnosis, and a lack of clear treatment guidelines (i.e., when to treat and the optimal treatment strategy). However, little evidence support the feasibility of SWD treatment even in the acute phase of stroke and its favorable effect on long-term cardiovascular and functional outcomes. Thus, sleep health recommendations and SWD treatment should be systematically embedded in secondary stroke prevention strategy. We therefore propose that the management of SWD associated with stroke should rely on a multidisciplinary approach, with an integrated diagnostic, treatment, and follow-up strategy. The challenges in the field are to improve post-stroke SWD diagnosis, prognosis and treatment, through a better appraisal of their pathophysiology and temporal evolution., (Copyright © 2023 Elsevier Masson SAS. All rights reserved.)

Restless legs syndrome (RLS) is a common neurological sensorimotor disorder that impairs sleep, mood and quality of life. RLS is defined by an urge to move the legs at rest that increases in the evening and at night, and is frequently associated with metabolic and cardiovascular diseases. Symptoms frequency, age at RLS onset, severity, familial history and consequences of RLS vary widely between patients. A genetic susceptibility, iron deficiency, dopamine deregulation, and possible hypo-adenosinergic state may play a role in the pathophysiology of RLS. Polysomnographic recordings found often periodic leg movements during sleep and wakefulness in patients with RLS. RLS can be classified as primary or comorbid with major diseases: iron deficiency, renal, neurological, rheumatological and lung diseases. First-line treatments are low-dose dopamine agonists, and alpha-2-delta ligands depending on the clinical context, and second/third line opiates for pharmacoresistant forms of RLS. Augmentation syndrome is a serious complication of dopamine agonists and should be prevented by using the recommended low dose. Despite an increase in knowledge, RLS is still underdiagnosed, poorly recognized, resulting in substantial individual health burden and socioeconomic coast, and education is urgently needed to increase awareness of this disabling disorder., (Copyright © 2023 Elsevier Masson SAS. All rights reserved.)

Narcolepsy type 1 (NT1) and type 2 (NT2), also known as narcolepsy with and without cataplexy, are sleep disorders that benefited from major scientific advances over the last two decades. NT1 is caused by the loss of hypothalamic neurons producing orexin/hypocretin, a neurotransmitter regulating sleep and wake, which can be measured in the cerebrospinal fluid (CSF). A low CSF level of hypocretin-1/orexin-A is a highly specific and sensitive biomarker, sufficient to diagnose NT1. Orexin-deficiency is responsible for the main NT1 symptoms: sleepiness, cataplexy, disrupted nocturnal sleep, sleep-related hallucinations, and sleep paralysis. In the absence of a lumbar puncture, the diagnosis is based on neurophysiological tests (nocturnal and diurnal) and the presence of the pathognomonic symptom cataplexy. In the revised version of the International Classification of sleep Disorders, 3rd edition (ICSD-3-TR), a sleep onset rapid eye movement sleep (REM) period (SOREMP) (i.e. rapid occurrence of REM sleep) during the previous polysomnography may replace the diurnal multiple sleep latency test, when clear-cut cataplexy is present. A nocturnal SOREMP is very specific but not sensitive enough, and the diagnosis of cataplexy is usually based on clinical interview. It is thus of crucial importance to define typical versus atypical cataplectic attacks, and a list of clinical features and related degrees of certainty is proposed in this paper (expert opinion). The time frame of at least three months of evolution of sleepiness to diagnose NT1 was removed in the ICSD-3-TR, when clear-cut cataplexy or orexin-deficiency are established. However, it was kept for NT2 diagnosis, a less well-characterized disorder with unknown clinical course and absence of biolo biomarkers; sleep deprivation, shift working and substances intake being major differential diagnoses. Treatment of narcolepsy is nowadays only symptomatic, but the upcoming arrival of non-peptide orexin receptor-2 agonists should be a revolution in the management of these rare sleep diseases., (Copyright © 2023 Elsevier Masson SAS. All rights reserved.)

Hypersomnolence is a major public health issue given its high frequency, its impact on academic/occupational functioning and on accidentology, as well as its heavy socio-economic burden. The positive and aetiological diagnosis is crucial, as it determines the therapeutic strategy. It must consider the following aspects: i) hypersomnolence is a complex concept referring to symptoms as varied as excessive daytime sleepiness, excessive need for sleep, sleep inertia, or drowsiness, all of which warrant specific dedicated investigations; ii) the boundary between physiological and abnormal hypersomnolence is blurred, since most symptoms can be encountered in the general population to varying degrees without being considered as pathological, meaning that their severity, frequency, context of occurrence and related impairment need to be carefully assessed; iii) investigation of hypersomnolence relies on scales/questionnaires as well as behavioural and neurophysiological tests, which measure one or more dimensions, keeping in mind the possible discrepancy between objective and subjective assessment; iv) aetiological reasoning is driven by knowledge of the main sleep regulation mechanisms, epidemiology, and associated symptoms. The need to assess hypersomnolence is growing, both for its management, and for assessing the efficacy of treatments. The landscape of tools available for investigating hypersomnolence is constantly evolving, in parallel with research into sleep physiology and technical advances. These investigations face the challenges of reconciling subjective perception and objective data, making tools accessible to as many people as possible and predicting the risk of accidents., (Copyright © 2023 Elsevier Masson SAS. All rights reserved.)

Symptoms of restless legs syndrome are relieved by movement. Whether a cognitive task decreases sensory discomfort remains understudied. We aimed to assess the frequency of patients with restless legs syndrome who report decreased sensory discomfort during cognitive activities, and quantify this decrease during a cognitive task. Three-hundred and fifty-eight consecutive adults with restless legs syndrome (age 55.17 ± 14.62 years; 55.87% women; 27.65% treated) answered the question: "Does the intensity of your restless legs syndrome symptoms decrease when you perform activities other than moving your legs?" rated on a nine-point Likert scale (from fully-agree to totally-disagree). A subgroup of 65 consecutive drug-free patients underwent an 80-min suggested immobilisation test at 20:00 hours to quantify legs discomfort on a visual analogue scale before polysomnography, including 40 patients performing a cognitive task (balloon analogue risk task) from the 60 to 80 min. A total of 130 (36.3%) patients reported a decrease, 158 (44.1%) no decrease, and 70 (19.5%) uncertain changes in severity of restless legs syndrome symptoms during cognitive activities, with a similar proportion whether treated or not. Patients experiencing a decrease had less severe restless legs syndrome symptoms. In the suggested immobilisation test, mixed-effect regression models showed that legs discomfort decreased in patients performing the cognitive task while it continued to increase in those without task, with a larger difference in patients reporting a self-reported decrease in restless legs syndrome during cognitive activities. In conclusion, one-third of patients reported a self-reported decrease of restless legs syndrome symptoms during cognitive activities, this improvement in restless legs syndrome was confirmed during a sustained cognitive task. Cognitive strategies could be implemented for the management of restless legs syndrome., (© 2022 European Sleep Research Society.)

Narcolepsy type 1 (NT1) is caused by a loss of hypocretin/orexin transmission. Risk factors include pandemic 2009 H1N1 influenza A infection and immunization with Pandemrix®. Here, we dissect disease mechanisms and interactions with environmental triggers in a multi-ethnic sample of 6,073 cases and 84,856 controls. We fine-mapped GWAS signals within HLA (DQ0602, DQB1*03:01 and DPB1*04:02) and discovered seven novel associations (CD207, NAB1, IKZF4-ERBB3, CTSC, DENND1B, SIRPG, PRF1). Significant signals at TRA and DQB1*06:02 loci were found in 245 vaccination-related cases, who also shared polygenic risk. T cell receptor associations in NT1 modulated TRAJ*24, TRAJ*28 and TRBV*4-2 chain-usage. Partitioned heritability and immune cell enrichment analyses found genetic signals to be driven by dendritic and helper T cells. Lastly comorbidity analysis using data from FinnGen, suggests shared effects between NT1 and other autoimmune diseases. NT1 genetic variants shape autoimmunity and response to environmental triggers, including influenza A infection and immunization with Pandemrix®., (© 2023. The Author(s).)

Introduction: Narcolepsy type 1 (NT1) is a rare, chronic and disabling neurological disease causing excessive daytime sleepiness and cataplexy. NT1 is characterized pathologically by an almost complete loss of neurons producing the orexin neuropeptides in the lateral hypothalamus. Genetic and environmental factors strongly suggest the involvement of the immune system in the loss of orexin neurons. The cerebrospinal fluid (CSF), secreted locally and surrounding the central nervous system (CNS), represents an accessible window into CNS pathological processes., Methods: To gain insight into the biological and molecular changes in NT1 patients, we performed a comparative proteomics analysis of the CSF from 21 recent-onset NT1 patients and from two control groups: group 1 with somatoform disorders, and group 2 patients with hypersomnia other than NT1, to control for any potential effect of sleep disturbances on CSF composition. To achieve an optimal proteomic coverage analysis, the twelve most abundant CSF proteins were depleted, and samples were analyzed by nano-flow liquid chromatography tandem mass spectrometry (nano-LC-MS/MS) using the latest generation of hybrid Orbitrap mass spectrometer., Results and Discussion: Our study allowed the identification and quantification of up to 1943 proteins, providing a remarkably deep analysis of the CSF proteome. Interestingly, gene set enrichment analysis indicated that the complement and coagulation systems were enriched and significantly activated in NT1 patients in both cohorts analyzed. Notably, the lectin and alternative complement pathway as well as the downstream lytic membrane attack complex were congruently increased in NT1. Our data suggest that the complement dysregulation in NT1 patients can contribute to immunopathology either by directly promoting tissue damage or as part of local inflammatory responses. We therefore reveal an altered composition of the CSF proteome in NT1 patients, which points to an ongoing inflammatory process contributed, at least in part, by the complement system., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Ayoub, Dauvilliers, Barateau, Vermeulen, Mouton-Barbosa, Marcellin, Gonzalez-de-Peredo, Gross, Saoudi and Liblau.)

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., (© 2022 European Sleep Research Society.)

Study Objectives: To assess the performances of alternative measures of the multiple sleep latency test (MSLT) to identify hypocretin-deficiency in patients with a complaint of hypersomnolence, including patients with narcolepsy., Methods: MSLT parameters from 374 drug-free patients with hypersomnolence, with complete clinical and polysomnographic (PSG) assessment and cerebrospinal hypocretin-1 measurement were collected. Conventional (sleep latency, number of sleep onset REM-SOREM-periods) and alternative (sleep duration, REM sleep latency and duration, sleep stage transitions) MSLT measures were compared as function of hypocretin-1 levels (≤110 vs > 110 pg/mL). We performed receiver-operating characteristics analyses to determine the best thresholds of MSLT parameters to identify hypocretin-deficiency in the global population and in subgroups of patients with narcolepsy (i.e. typical cataplexy and/or positive PSG/MSLT criteria, n = 223)., Results: Patients with hypocretin-deficiency had shorter mean sleep and REM sleep latencies, longer mean sleep and REM sleep durations and more direct REM sleep transitions during the MSLT. The current standards of MSLT/PSG criteria identified hypocretin-deficient patients with a sensitivity of 0.87 and a specificity of 0.69, and 0.81/0.99 when combined with cataplexy. A mean REM sleep duration ≥ 4.1 min best identified hypocretin-deficiency in patients with hypersomnolence (AUC = 0.932, sensitivity 0.87, specificity 0.86) and ≥ 5.7 min in patients with narcolepsy (AUC = 0.832, sensitivity 0.77, specificity 0.82)., Conclusion: Compared to the current neurophysiological standard criteria, alternative MSLT parameters would better identify hypocretin-deficiency among patients with hypersomnolence and those with narcolepsy. We highlighted daytime REM sleep duration as a relevant neurophysiological biomarker of hypocretin-deficiency to be used in clinical and research settings., (© The Author(s) 2022. Published by Oxford University Press on behalf of Sleep Research Society. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Background and Objectives: To explore the first coronavirus disease 2019 (COVID-19) lockdown effect on sleep symptoms in patients with narcolepsy, idiopathic hypersomnia (IH), and restless legs syndrome (RLS)., Methods: Between March and May 2020, a sample of adult patients regularly followed up in a Reference Hospital Sleep Unit (299 with narcolepsy, 260 with IH, and 254 with RLS) was offered an online survey assessing their sleep-wake habits, daily activities, medication intake, and validated scales: International RLS Study Group questionnaire, Narcolepsy Severity Scale (NSS), IH Severity Scale (IHSS), Epworth Sleepiness Scale (ESS), Insomnia Severity Index, Beck Depression Inventory-II, and European Quality of Life (QoL) scale. The survey was proposed once, and the questions were answered for the prelockdown (recall of the month before the confinement) and the lockdown (time of study) periods., Results: Overall, 331 patients completed the survey (response rate 40.7%): 102 with narcolepsy, 81 with IH, and 148 with RLS. All patients reported later bedtimes, with reduced differences for time in bed (TIB) and total sleep time (TST) over 24 hours between weekdays and weekends. Patients with narcolepsy spent more TIB and increased TST overnight, with more daytime napping. They had more awakenings, higher ESS scores, lower QoL, and no NSS changes. Patients with IH also increased their TIB, TST overnight and 24 hours on weekdays. Nocturnal sleep latency and the number of awakenings increased but with no change in ESS, QoL, and IHSS scores. Patients with RLS reported longer nocturnal sleep latency, more awakenings, more naps, decreased TIB, and TST overnight. RLS severity increased while QoL decreased. A significant portion of patients reported disease worsening during the lockdown (narcolepsy: 39.4%, IH: 43.6%, and RLS: 32.8%), and some patients stopped or lowered their medication (narcolepsy: 22.5%, IH: 28%, and RLS: 9.5%)., Discussion: During the lockdown, all patients reported later bedtimes; those with narcolepsy and IH extended their sleep duration unlike patients with RLS. These changes were often associated with negative consequences on QoL. In the current context of recurrent COVID-19 waves, the recent development of teleconsultations should enable physicians to monitor patients with chronic sleep disorders more closely and to recommend optimized sleep schedules and duration, in order to prevent psychological problems and improve their QoL., (© 2022 American Academy of Neurology.)

The orexins, also known as hypocretins, are two neuropeptides (orexin A and B or hypocretin 1 and 2) produced by a few thousand neurons located in the lateral hypothalamus that were independently discovered by two research groups in 1998. Those two peptides bind two receptors (orexin/hypocretin receptor 1 and receptor 2) that are widely distributed in the brain and involved in the central physiological regulation of sleep and wakefulness, orexin receptor 2 having the major role in the maintenance of arousal. They are also implicated in a multiplicity of other functions, such as reward seeking, energy balance, autonomic regulation and emotional behaviours. The destruction of orexin neurons is responsible for the sleep disorder narcolepsy with cataplexy (type 1) in humans, and a defect of orexin signalling also causes a narcoleptic phenotype in several animal species. Orexin discovery is unprecedented in the history of sleep research, and pharmacological manipulations of orexin may have multiple therapeutic applications. Several orexin receptor antagonists were recently developed as new drugs for insomnia, and orexin agonists may be the next-generation drugs for narcolepsy. Given the broad range of functions of the orexin system, these drugs might also be beneficial for treating various conditions other than sleep disorders in the near future., (© 2022 European Sleep Research Society.)

This article addresses the clinical presentation, diagnosis, pathophysiology and management of narcolepsy type 1 and 2, with a focus on recent findings. A low level of hypocretin-1/orexin-A in the cerebrospinal fluid is sufficient to diagnose narcolepsy type 1, being a highly specific and sensitive biomarker, and the irreversible loss of hypocretin neurons is responsible for the main symptoms of the disease: sleepiness, cataplexy, sleep-related hallucinations and paralysis, and disrupted nocturnal sleep. The process responsible for the destruction of hypocretin neurons is highly suspected to be autoimmune, or dysimmune. Over the last two decades, remarkable progress has been made for the understanding of these mechanisms that were made possible with the development of new techniques. Conversely, narcolepsy type 2 is a less well-defined disorder, with a variable phenotype and evolution, and few reliable biomarkers discovered so far. There is a dearth of knowledge about this disorder, and its aetiology remains unclear and needs to be further explored. Treatment of narcolepsy is still nowadays only symptomatic, targeting sleepiness, cataplexy and disrupted nocturnal sleep. However, new psychostimulants have been recently developed, and the upcoming arrival of non-peptide hypocretin receptor-2 agonists should be a revolution in the management of this rare sleep disease, and maybe also for disorders beyond narcolepsy., (© 2022 European Sleep Research Society.)

Study Objectives: Despite its high frequency in narcolepsy type 1(NT1), disrupted nocturnal sleep (DNS) remains understudied, and its determinants have been poorly assessed. We aimed to determine the clinical, polysomnographic (PSG), and biological variables associated with DNS in a large sample of patients with NT1, and to evaluate the effect of medication on DNS and its severity., Methods: Two hundred and forty-eight consecutive adult patients with NT1 (145 untreated, 103 treated) were included at the National Reference Center for Narcolepsy-France; 51 drug-free patients were reevaluated during treatment. DNS, assessed with the Narcolepsy Severity Scale (NSS), was categorized in four levels (absent, mild, moderate, severe). Clinical characteristics, validated questionnaires, PSG parameters (sleep fragmentation markers: sleep (SB) and wake bouts (WB), transitions), objective sleepiness, and orexin-A levels were assessed., Results: In drug-free patients, DNS severity was associated with higher scores on NSS, higher sleepiness, anxiety/depressive symptoms, autonomic dysfunction, worse quality of life (QoL). Patients with moderate/severe DNS (59%) had increased sleep onset REM periods, lower sleep efficiency, longer wake after sleep onset, more N1, SB, WB, sleep instability, transitions. In treated patients, DNS was associated with the same clinical data, and antidepressant use; but only with longer REM sleep latency on PSG. During treatment, sleepiness, NSS scores, depressive symptoms decreased, as well as total sleep time, WB, SB, transitions. DNS improved in 55% of patients, without predictors except more baseline anxiety., Conclusion: DNS complaint is frequent in NT1, associated with disease severity based on NSS, several PSG parameters, and objective sleepiness in untreated and treated conditions. DNS improves with treatment. We advocate the systematic assessment of this symptom and its inclusion in NT1 management strategy., (© The Author(s) 2022. Published by Oxford University Press on behalf of Sleep Research Society. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Background and Objectives: Recent studies fueled doubts as to whether all currently defined central disorders of hypersomnolence are stable entities, especially narcolepsy type 2 and idiopathic hypersomnia. New reliable biomarkers are needed, and the question arises of whether current diagnostic criteria of hypersomnolence disorders should be reassessed. The main aim of this data-driven observational study was to see whether data-driven algorithms would segregate narcolepsy type 1 and identify more reliable subgrouping of individuals without cataplexy with new clinical biomarkers., Methods: We used agglomerative hierarchical clustering, an unsupervised machine learning algorithm, to identify distinct hypersomnolence clusters in the large-scale European Narcolepsy Network database. We included 97 variables, covering all aspects of central hypersomnolence disorders such as symptoms, demographics, objective and subjective sleep measures, and laboratory biomarkers. We specifically focused on subgrouping of patients without cataplexy. The number of clusters was chosen to be the minimal number for which patients without cataplexy were put in distinct groups., Results: We included 1,078 unmedicated adolescents and adults. Seven clusters were identified, of which 4 clusters included predominantly individuals with cataplexy. The 2 most distinct clusters consisted of 158 and 157 patients, were dominated by those without cataplexy, and among other variables, significantly differed in presence of sleep drunkenness, subjective difficulty awakening, and weekend-week sleep length difference. Patients formally diagnosed as having narcolepsy type 2 and idiopathic hypersomnia were evenly mixed in these 2 clusters., Discussion: Using a data-driven approach in the largest study on central disorders of hypersomnolence to date, our study identified distinct patient subgroups within the central disorders of hypersomnolence population. Our results contest inclusion of sleep-onset REM periods in diagnostic criteria for people without cataplexy and provide promising new variables for reliable diagnostic categories that better resemble different patient phenotypes. Cluster-guided classification will result in a more solid hypersomnolence classification system that is less vulnerable to instability of single features., (Copyright © 2022 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the American Academy of Neurology.)

Purpose: Narcolepsy type-1 (NT1) is a rare chronic neurological sleep disorder with excessive daytime sleepiness (EDS) as usual first and cataplexy as pathognomonic symptom. Shortening the NT1 diagnostic delay is the key to reduce disease burden and related low quality of life. Here we investigated the changes of diagnostic delay over the diagnostic years (1990-2018) and the factors associated with the delay in Europe., Patients and Methods: We analyzed 580 NT1 patients (male: 325, female: 255) from 12 European countries using the European Narcolepsy Network database. We combined machine learning and linear mixed-effect regression to identify factors associated with the delay., Results: The mean age at EDS onset and diagnosis of our patients was 20.9±11.8 (mean ± standard deviation) and 30.5±14.9 years old, respectively. Their mean and median diagnostic delay was 9.7±11.5 and 5.3 (interquartile range: 1.7-13.2 years) years, respectively. We did not find significant differences in the diagnostic delay over years in either the whole dataset or in individual countries, although the delay showed significant differences in various countries. The number of patients with short (≤2-year) and long (≥13-year) diagnostic delay equally increased over decades, suggesting that subgroups of NT1 patients with variable disease progression may co-exist. Younger age at cataplexy onset, longer interval between EDS and cataplexy onsets, lower cataplexy frequency, shorter duration of irresistible daytime sleep, lower daytime REM sleep propensity, and being female are associated with longer diagnostic delay., Conclusion: Our findings contrast the results of previous studies reporting shorter delay over time which is confounded by calendar year, because they characterized the changes in diagnostic delay over the symptom onset year. Our study indicates that new strategies such as increasing media attention/awareness and developing new biomarkers are needed to better detect EDS, cataplexy, and changes of nocturnal sleep in narcolepsy, in order to shorten the diagnostic interval., Competing Interests: Prof. Dr. Giuseppe Plazzi reports personal fees from Jazz Pharmaceuticals, Takeda, Idorsia, and Bioprojet, outside the submitted work. Dr Gert Jan Lammers reports grant for investigator initiated study, consultancy, and/or Member Advisory Board from Jazz Pharmaceuticals, UCB Pharma, and Bioprojet Pharma, outside the submitted work. Dr Sebastiaan Overeem reports consulting fees paid to institution from Bioproject, Takeda, Jazz Pharmaceuticals, and UCB Pharma, outside the submitted work. Dr Karel Sonka reports grants from Czech Ministry of Health, during the conduct of the study; personal fees for consulting fees or clinical trial fees from AOP Orphan, Jazz, Flamel-Avadel, and Sanofi, outside the submitted work. Prof. Dr. Birgit Högl reports speaker fees from Abbvie and Jazz, and consulting fees from Lundbeck, outside the submitted work. Dr Lucie Barateau reports funding for seminars from Bioprojet and Jazz, board engagement fees from Takeda, and travel reimbursements for conferences from UCB Pharma, outside the submitted work. Dr Rolf Fronczek reports grants and/or personal fees from Bioprojet for lecture fee and advisory board, research grant (co-applicant), research grants as co-applicant from Jazz Pharma, personal fees from Takeda for advisory board, outside the submitted work. The authors report no other conflicts of interest in this work., (© 2022 Zhang et al.)

Study Objectives: To assess the frequency, determinants, and clinical impact of clinical rapid eye movement (REM) and non-REM (NREM) parasomnias in adult patients with narcolepsy type 1 (NT1), narcolepsy type 2 (NT2), and idiopathic hypersomnia compared with 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 idiopathic hypersomnia) and 595 healthy controls., Results: Except for sleep-related eating disorder, current NREM parasomnias were rare in all patient groups and controls. Sleep-related eating disorder was more frequent in NT1 patients (7.9% vs 1.8% in NT2 patients, 2.1% in patients with idiopathic hypersomnia, and 1% in controls) and associated with disrupted nighttime sleep (odds ratio = 3.9) and nocturnal eating in full awareness (odds ratio = 6.9) but not with sex. Clinical REM sleep behavior disorder was more frequent in NT1 patients (41.4%, half being violent) than in NT2 patients (13.2%) and affected men more often than women (odds ratio = 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 idiopathic hypersomnia (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 for sleep-related eating disorder) are rare and do not worsen sleepiness. In contrast, REM parasomnias are prevalent (especially in NT1) and are associated with male sex, disrupted nighttime sleep, depressive symptoms, and antidepressant use., Citation: Leu-Semenescu S, Maranci J-B, Lopez R, et al. Comorbid parasomnias in narcolepsy and idiopathic hypersomnia: more REM than NREM parasomnias. J Clin Sleep Med . 2022;18(5):1355-1364., (© 2022 American Academy of Sleep Medicine.)

Primary Sjögren’s syndrome (pSS) can be associated with neurological and cognitive involvement, negatively affecting patients’ quality of life. The aim of this study was to assess whether pSS patients are at higher risk of hospitalization for neurological diseases. Through a nationwide retrospective study using the French Health insurance database (based on International Classification for Disease codes, ICD-10), we selected patients hospitalized with new-onset pSS between 2011 and 2018. We compared the incidence of hospitalization for dementia, multiple sclerosis (MS), encephalitis, and peripheral neuropathy with an age- and sex-matched (1:10) hospitalized control group. Adjusted Hazard Ratios (aHR) considered confounding factors, particularly socio-economic status and cardiovascular diseases. We analyzed 25,661 patients hospitalized for pSS, compared with 252,543 matched patients. The incidence of hospitalization for dementia was significantly higher in pSS patients (aHR = 1.27 (1.04−1.55); p = 0.018), as well as the incidence of hospitalization for MS, encephalitis, and inflammatory polyneuropathies (aHR = 3.66 (2.35−5.68), p < 0.001; aHR = 2.66 (1.22−5.80), p = 0.014; and aHR = 23.2 (12.2−44.5), p < 0.001, respectively). According to ICD-10 codes, pSS patients exhibited a higher incidence of hospitalization for dementia, encephalitis, MS, and peripheral neuropathies than controls. Physicians must be aware of these neurological risks to choose the most appropriate diagnostic work-up.

Background: Whether depression and suicide thoughts relate to restless legs syndrome (RLS) or comorbidities associated with RLS remain unclear., Objectives: To determine frequency of depressive symptoms and suicidal thoughts in patients with RLS and their change after RLS treatment, associated clinical and polysomnographic factors, and current major depressive episode (MDE) frequency and suicide risk in RLS., Methods: Overall, 549 untreated patients with RLS and 549 age-, sex-, and education level-matched controls completed a standardized evaluation, including the Beck Depression Inventory-II that has one item on suicide thoughts. Patients underwent a polysomnographic recording and completed the Urgency, Premeditation, Perseverance, Sensation Seeking Impulsive Behavior scale. In a subgroup of 153 patients, current MDE and suicide risk were assessed with the face-to-face Mini-International Neuropsychiatric Interview (MINI). A subgroup of 152 patients were evaluated in untreated and treated conditions., Results: The frequency of depressive symptoms (32.5%) and suicidal thoughts (28%) was 10-fold and 3-fold higher, respectively, in patients with RLS than controls. Current MDE (10.5%) and suicidal risk (19.9%) (MINI) were also high. Moderate-to-severe depressive symptoms were associated with young age, female sex, insomnia symptoms, and urgency dimension. The suicide risk was associated with depression, impulsiveness, and RLS severity. RLS treatment improved depressive symptoms but not suicidal thoughts., Conclusion: The rate of depressive symptoms, depression, and suicidal thoughts/risk was higher in patients with RLS, with key associations with insomnia symptoms, urgency dimension, and RLS severity. These results emphasize the importance of detecting these symptoms in current practice and of evaluating their change after treatment, especially in young women, to improve RLS management. © 2022 International Parkinson and Movement Disorder Society., (© 2022 International Parkinson and Movement Disorder Society.)

Study Objectives: To describe the phenotype of narcolepsy with intermediate cerebrospinal fluid hypocretin-1 levels (CSF hcrt-1)., Methods: From 1600 consecutive patients with narcolepsy from Bologna and Montpellier sleep centers, we selected patients with intermediate CSF hcrt-1 levels (110-200 pg/mL). Clinical, neurophysiological, and biological data were contrasted for the presence of cataplexy, human leukocyte haplotype (HLA)-DQB1*06:02, and median CSF hcrt-1 levels (149.34 pg/mL)., Results: Forty-five (55% males, aged 35 ± 17 years) patients (2.8% of all cases) were included. Thirty-three (73%) were HLA-DQB1*06:02, 29 (64%) reported cataplexy (21, 72.4% with typical features), and 5 (11%) had presumed secondary etiology. Cataplexy was associated with other core narcolepsy symptoms, increased sleep onset rapid eye movement periods, and nocturnal sleep disruption. Cataplexy and irrepressible daytime sleep were more frequent in HLA-DQB1*06:02 positive patients. Lower CSF hcrt-1 levels were associated with hallucinations., Conclusions: Narcolepsy with intermediate CSF hcrt-1 level is a rare condition with heterogeneous phenotype. HLA-DQB1*06:02 and lower CSF hcrt-1 were associated with typical narcolepsy features, calling for future research to distinguish incomplete from secondary narcolepsy forms., (© Sleep Research Society 2021. Published by Oxford University Press on behalf of the Sleep Research Society. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Background and Objectives: Narcolepsy type 1 (NT1) is an orphan brain disorder caused by the irreversible destruction of orexin neurons. Metabolic disturbances are common in patients with NT1 who have a body mass index (BMI) 10% to 20% higher than the general population, with one-third being obese (BMI >30 kg/m 2 ). Besides the destruction of orexin neurons in NT1, the metabolic alterations in obese and nonobese patients with NT1 remain unknown. The aim of this study was to identify possible differences in plasma metabolic profiles between patients with NT1 and controls as a function of their BMI status., Methods: We used a targeted liquid chromatography-mass spectrometry metabolomics approach to measure 141 circulating, low-molecular-weight metabolites in drug-free fasted plasma samples from 117 patients with NT1 (including 41 obese individuals) compared with 116 BMI-matched controls (including 57 obese individuals)., Results: Common metabolites driving the difference between patients with NT1 and controls, regardless of BMI, were identified, namely sarcosine, glutamate, nonaylcarnitine (C9), 5 long-chain lysophosphatidylcholine acyls, 1 sphingolipid, 12 phosphatidylcholine diacyls, and 11 phosphatidylcholine acyl-akyls, all showing increased concentrations in NT1. Metabolite concentrations significantly affected by NT1 (n = 42) and BMI category (n = 40) showed little overlap (n = 5). Quantitative enrichment analysis revealed common metabolic pathways that were implicated in the NT1/control differences in both normal BMI and obese comparisons, namely glycine and serine, arachidonic acid, and tryptophan metabolism. The metabolites driving these differences were glutamate, sarcosine, and ornithine (glycine and serine metabolism); glutamate and PC aa C34:4 (arachidonic acid metabolism); and glutamate, serotonin, and tryptophan (tryptophan metabolism). Linear metabolite-endophenotype regression analyses highlight that as part of the NT1 metabolic phenotype, most of the relationships between the sleep parameters (i.e., slow-wave sleep duration, sleep latency, and periodic leg movement) and metabolite concentrations seen in the controls were lost., Discussion: These results represent the most comprehensive metabolic profiling of patients with NT1 as a function of BMI and propose some metabolic diagnostic biomarkers for NT1, namely glutamate, sarcosine, serotonin, tryptophan, nonaylcarnitine, and some phosphatidylcholines. The metabolic pathways identified offer, if confirmed, possible targets for treatment of obesity in NT1., Classification of Evidence: This study provides Class II evidence that a distinct metabolic profile can differentiate patients with NT1 from patients without the disorder., (© 2022 American Academy of Neurology.)

Study Objectives: To assess the responsiveness of the Idiopathic Hypersomnia Severity Scale (IHSS) to medications and estimate the minimum clinically important difference, to report clinically relevant score ranges, and to confirm its psychometric properties and whether items need to be weighted in drug-free and treated patients with idiopathic hypersomnia (IH)., Methods: Two-hundred twenty-six (166 drug-free and 60 treated) patients with IH (cross-sectional sample) completed the 14-item IHSS to quantify the severity of the 3 major IH symptoms (excessive daytime sleepiness, prolonged nighttime sleep, and sleep inertia) and consequences; 77 untreated patients were evaluated again after treatment (longitudinal sample). Patients filled in the Epworth Sleepiness Scale, Beck Depression Inventory II, and European Quality of Life questionnaires., Results: The IHSS confirmed adequate psychometric properties with a factor analysis indicating a 3-component solution. IHSS total score was lower in treated than untreated patients, with a mean difference of 4-5 points in the cross-sectional and longitudinal samples. Distribution-based methods were used to estimate that 4 points represented the minimum clinically important difference. Four severity levels were defined with between-group differences related to treatment. The probability of having severe sleepiness, depressive symptoms, and low quality of life increased with the severity level. Our results showed that IHSS item-weighting was not necessary., Conclusions: The IHSS is a valid and reliable tool to quantify IH symptoms, with 4 severity score levels of clinical importance. The IHSS has adequate psychometric properties and can detect symptom changes after treatment. These findings should stimulate its use in clinical settings and in research studies., Citation: Rassu AL, Evangelista E, Barateau L, et al. Idiopathic Hypersomnia Severity Scale to better quantify symptoms severity and their consequences in idiopathic hypersomnia. J Clin Sleep Med . 2022;18(2):617-629., (© 2022 American Academy of Sleep Medicine.)

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., (© 2022 American Academy of Sleep Medicine.)

Study Objectives: Sleep inertia is a frequent and disabling symptom in idiopathic hypersomnia (IH), but poorly defined and without objective measures. The study objective was to determine whether the psychomotor vigilance task (PVT) can reliably measure sleep inertia in patients with IH or other sleep disorders (non-IH)., Methods: A total of 62 (51 women, mean age: 27.7 ± 9.2) patients with IH and 140 (71 women, age: 33.3 ± 12.1) with non-IH (narcolepsy = 29, non-specified hypersomnolence [NSH] = 47, obstructive sleep apnea = 39, insomnia = 25) were included. Sleep inertia and sleep drunkenness in the last month (M-sleep inertia) and on PVT day (D-sleep inertia) were assessed with three items of the Idiopathic Hypersomnia Severity Scale (IHSS), in drug-free conditions. The PVT was performed four times (07:00 pm, 07:00 am, 07:30 am, and 11:00 am) and three metrics were used: lapses, mean 1/reaction time (RT), and slowest 10% 1/RT., Results: Sleep inertia was more frequent in patients with IH than non-IH (56.5% and 43.6% with severe sleep inertia in the past month, including 24% and 12% with sleep drunkenness). Lapse number increase and slowest 10% 1/RT decrease, particularly at 07:00 am and 07:30 am, were proportional with M-sleep inertia severity, but regardless of sleep drunkenness and sleep disorders. Similar results were obtained when PVT results were compared in patients with/without D-sleep inertia, with the largest increase of the lapse number at 07:00 am and 07:30 am associated with severe sleep inertia and sleep drunkenness., Conclusions: PVT is a reliable and objective measure of sleep inertia that might be useful for its characterization, management, and follow-up in patients with IH., (© Sleep Research Society 2021. Published by Oxford University Press on behalf of the Sleep Research Society. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Primary Sjögren's syndrome (pSS) is an autoimmune disease, associated with a high risk of lymphoma. Mounting evidence suggests that cardiovascular morbidity and mortality are higher in patients with pSS, although data are heterogeneous. The aim of this study was to assess whether pSS patients are at higher risk of hospitalisation for cardiovascular events (CVEs), venous thromboembolic events (VTEs), pulmonary hypertension (PH), and sleep apnoea syndrome (SAS). Through a nationwide population-based retrospective study using the French health insurance database, we selected new-onset pSS in-patients hospitalised between 2011 and 2018. We compared the incidence of CVEs (ischemic heart diseases (IHDs), strokes, and heart failure), SAS, VTEs, and PH with an age- and sex-matched (1:10) hospitalised control group. The calculations of adjusted hazard ratios (aHR) included available confounding factors. We studied 25,661 patients hospitalised for pSS compared with 252,543 matched patients. The incidence of hospitalisation for IHD, SAS, and PH was significantly higher in pSS patients (aHR: 1.20 (1.06-1.34); p = 0.003, aHR: 1.97 (1.70-2.28); p < 0.001, and aHR: 3.32 (2.10-5.25); p < 0.001, respectively), whereas the incidence of stroke, heart failure, and VTE was the same between groups. Further prospective studies are needed to confirm these results and to explore the pathophysiological mechanisms involved.

Objective: We validated the Narcolepsy Severity Scale (NSS) in adults with narcolepsy type 1 (NT1) to quantify the severity, frequency, and consequences of the 5 key narcolepsy symptoms over the last month, and we now developed the Pediatric NSS (NSS-P); thus, the aims of this study were to assess NSS-P psychometric properties, validity, and reliability, and to evaluate its responsiveness to treatment in a well-characterized sample of children and adolescents with NT1., Methods: The NSS was reformulated for children, and the item about driving was removed. The total score of the 14-item NSS-P ranges from 0 to 54, and higher scores reflect more severe disease. Children and adolescents (n = 209, 6-17 years of age) with NT1 diagnosed in 2 Reference Centers for Narcolepsy in France were consecutively asked to fill in the NSS-P. The scale was fully and correctly completed by 160 (10-18 years of age, 68 untreated). Moreover, 65 participants completed it twice (33 before/during treatment, and 32 under the same treatment). The NSS-P psychometric properties, score changes before/during treatment, and convergent validity with other clinical parameters were assessed., Results: The NSS-P showed adequate psychometric properties with significant item-total score correlations. Factor analysis indicated a 4-factor solution with good reliability. The NSS-P score was lower in treated than untreated patients with a mean difference of 3.71 ± 1.45, with a minimum clinically important difference between untreated and treated patients in the longitudinal sample estimated at 4 points. Four severity levels were defined (mild, moderate, severe, very severe) with between-group differences related to treatment. The NSS-P total score was associated with self-reported sleepiness, insomnia, and depressive symptoms. Its temporal stability was satisfactory., Discussion: We validated a brief instrument to assess NT1 symptom frequency, severity, and consequences in ≥10-year-old children and adolescents with 4 clinically relevant severity score ranges. This scale constitutes a relevant tool to improve and provide guidance for NT1 management in pediatric populations. The ease of administration, its good psychometric properties, and its sensitivity to detect symptom changes after treatment ensure future use of the NSS-P in clinical and research settings., (© 2021 American Academy of Neurology.)

Study Objectives: Whether the cause of daytime sleepiness in narcolepsy type 1 (NT1) is a direct consequence of the loss of orexin (ORX) neurons or whether low orexin reduces the efficacy of the monoaminergic systems to promote wakefulness is unclear. The neurobiology underlying sleepiness in other central hypersomnolence disorders, narcolepsy type 2 (NT2), and idiopathic hypersomnia (IH), is currently unknown., Methods: Eleven biogenic amines including the monoaminergic neurotransmitters and their metabolites and five trace amines were measured in the cerebrospinal fluid (CSF) of 94 drug-free subjects evaluated at the French National Reference Center for Narcolepsy: 39 NT1(orexin-deficient) patients, 31 patients with objective sleepiness non orexin-deficient (NT2 and IH), and 24 patients without objective sleepiness., Results: Three trace amines were undetectable in the sample: tryptamine, octopamine, and 3-iodothyronamine. No significant differences were found among the three groups for quantified monoamines and their metabolites in crude and adjusted models; however, CSF 5-hydroxyindoleacetic acid (5-HIAA) levels tended to increase in NT1 compared to other patients after adjustment. Most of the biomarkers were not associated with ORX-A levels, clinical or neurophysiological parameters, but a few biomarkers (e.g. 3-methoxy-4-hydroxyphenylglycol and norepinephrine) correlated with daytime sleepiness and high rapid eye movement (REM) sleep propensity., Conclusions: We found no striking differences among CSF monoamines, their metabolites and trace amine levels, and few associations between them and key clinical or neurophysiological parameters in NT1, NT2/IH, and patients without objective sleepiness. Although mostly negative, these findings are a significant contribution to our understanding of the neurobiology of hypersomnolence in these disorders that remain mysterious and deserve further exploration., (© Sleep Research Society 2021. Published by Oxford University Press on behalf of the Sleep Research Society. All rights reserved. For permissions, please email: journals.permissions@oup.com.)