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Knez R, Niksic M, Omerovic E. Orexin/hypocretin system dysfunction in patients with Takotsubo syndrome: A novel pathophysiological explanation. Front Cardiovasc Med 2022; 9:1016369. [PMID: 36407467 PMCID: PMC9670121 DOI: 10.3389/fcvm.2022.1016369] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Accepted: 10/05/2022] [Indexed: 09/19/2023] Open
Abstract
Takotsubo syndrome (TTS) is an acute heart failure syndrome. Emotional or physical stressors are believed to precipitate TTS, while the pathophysiological mechanism is not yet completely understood. During the coronavirus disease (COVID-19) pandemic, an increased incidence of TTS has been reported in some countries; however, the precise pathophysiological mechanism for developing TTS with acute COVID-19 infection is unknown. Nevertheless, observing the symptoms of COVID-19 might lead to new perspectives in understanding TTS pathophysiology, as some of the symptoms of the COVID-19 infection could be assessed in the context of an orexin/hypocretin-system dysfunction. Orexin/hypocretin is a cardiorespiratory neuromodulator that acts on two orexin receptors widely distributed in the brain and peripheral tissues. In COVID-19 patients, autoantibodies against one of these orexin receptors have been reported. Orexin-system dysfunction affects a variety of systems in an organism. Here, we review the influence of orexin-system dysfunction on the cardiovascular system to propose its connection with TTS. We propose that orexin-system dysfunction is a potential novel explanation for the pathophysiology of TTS due to direct or indirect dynamics of orexin signaling, which could influence cardiac contractility. This is in line with the conceptualization of TTS as a cardiovascular syndrome rather than merely a cardiac abnormality or cardiomyopathy. To the best of our knowledge, this is the first publication to present a plausible connection between TTS and orexin-system dysfunction. We hope that this novel hypothesis will inspire comprehensive studies regarding orexin's role in TTS pathophysiology. Furthermore, confirmation of this plausible pathophysiological mechanism could contribute to the development of orexin-based therapeutics in the treatment and prevention of TTS.
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Affiliation(s)
- Rajna Knez
- Gillberg Neuropsychiatry Centre, Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
- Research and Development, Department of Women's and Child Health, Skaraborg Hospital, Skövde, Sweden
- Institution for Health, School of Health Sciences, University of Skövde, Skövde, Sweden
| | - Milan Niksic
- Department of Cardiology, Skaraborg Hospital, Skövde, Sweden
| | - Elmir Omerovic
- Department of Molecular and Clinical Medicine/Cardiology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
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Demidova A, Kahl E, Fendt M. Orexin deficiency affects sensorimotor gating and its amphetamine-induced impairment. Prog Neuropsychopharmacol Biol Psychiatry 2022; 116:110517. [PMID: 35101602 DOI: 10.1016/j.pnpbp.2022.110517] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 01/19/2022] [Accepted: 01/20/2022] [Indexed: 11/17/2022]
Abstract
The orexin neuropeptides have an important role in the regulation of the sleep/wake cycle and foraging, as well as in reward processing and emotions. Furthermore, recent research implicates the orexin system in different behavioral endophenotypes of neuropsychiatric diseases such as social avoidance and cognitive flexibility. Utilizing orexin-deficient mice, the present study tested the hypothesis that orexin is involved in two further mouse behavioral endophenotypes of neuropsychiatric disorders, i.e., sensorimotor gating and amphetamine sensitivity. The data revealed that orexin-deficient mice expressed a deficit in sensorimotor gating, measured by prepulse inhibition of the startle response. Amphetamine treatment impaired prepulse inhibition in wildtype and heterozygous orexin-deficient mice, but had no effects in homozygous orexin-deficient mice. Furthermore, locomotor activity and center time in the open field was not affected by orexin deficiency but was similarly increased or decreased, respectively, by amphetamine treatment in all genotypes. These data indicate that the orexin system modulates prepulse inhibition and is involved in mediating amphetamine's effect on prepulse inhibition. Future studies should investigate whether pharmacological manipulations of the orexin system can be used to treat neuropsychiatric diseases associated with deficits in sensorimotor gating, such as schizophrenia or attention deficit hyperactivity disorder.
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Affiliation(s)
- Alexandrina Demidova
- Institute for Pharmacology and Toxicology, Otto-von-Guericke University Magdeburg, Germany; Psychology Master Program, Otto-von-Guericke University Magdeburg, Germany
| | - Evelyn Kahl
- Institute for Pharmacology and Toxicology, Otto-von-Guericke University Magdeburg, Germany
| | - Markus Fendt
- Institute for Pharmacology and Toxicology, Otto-von-Guericke University Magdeburg, Germany; Psychology Master Program, Otto-von-Guericke University Magdeburg, Germany; Center for Behavioral Brain Sciences, Otto-von-Guericke University Magdeburg, Germany.
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Sun Y, Tisdale R, Park S, Ma SC, Heu J, Haire M, Allocca G, Yamanaka A, Morairty SR, Kilduff TS. The development of sleep/wake disruption and cataplexy as hypocretin/orexin neurons degenerate in male vs. female Orexin/tTA; TetO-DTA Mice. Sleep 2022; 45:6532492. [PMID: 35182424 PMCID: PMC9742901 DOI: 10.1093/sleep/zsac039] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Revised: 12/23/2021] [Indexed: 01/10/2023] Open
Abstract
Narcolepsy Type 1 (NT1), a sleep disorder with similar prevalence in both sexes, is thought to be due to loss of the hypocretin/orexin (Hcrt) neurons. Several transgenic strains have been created to model this disorder and are increasingly being used for preclinical drug development and basic science studies, yet most studies have solely used male mice. We compared the development of narcoleptic symptomatology in male vs. female orexin-tTA; TetO-DTA mice, a model in which Hcrt neuron degeneration can be initiated by removal of doxycycline (DOX) from the diet. EEG, EMG, subcutaneous temperature, gross motor activity, and video recordings were conducted for 24-h at baseline and 1, 2, 4, and 6 weeks after DOX removal. Female DTA mice exhibited cataplexy, the pathognomonic symptom of NT1, by Week 1 in the DOX(-) condition but cataplexy was not consistently present in males until Week 2. By Week 2, both sexes showed an impaired ability to sustain long wake bouts during the active period, the murine equivalent of excessive daytime sleepiness in NT1. Subcutaneous temperature appeared to be regulated at lower levels in both sexes as the Hcrt neurons degenerated. During degeneration, both sexes also exhibited the "Delta State", characterized by sudden cessation of activity, high delta activity in the EEG, maintenance of muscle tone and posture, and the absence of phasic EMG activity. Since the phenotypes of the two sexes were indistinguishable by Week 6, we conclude that both sexes can be safely combined in future studies to reduce cost and animal use.
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Affiliation(s)
- Yu Sun
- Biosciences Division, SRI International, Menlo Park, CA, USA
| | | | | | - Shun-Chieh Ma
- Biosciences Division, SRI International, Menlo Park, CA, USA
| | - Jasmine Heu
- Biosciences Division, SRI International, Menlo Park, CA, USA
| | - Meghan Haire
- Biosciences Division, SRI International, Menlo Park, CA, USA
| | | | - Akihiro Yamanaka
- Department of Neuroscience II, Research Institute of Environmental Medicine, Nagoya University, Japan,Department of Neural Regulation, Nagoya University Graduate School of Medicine, Japan
| | | | - Thomas S Kilduff
- Corresponding author. Thomas S. Kilduff, Center for Neuroscience, Biosciences Division SRI International, 333 Ravenswood Ave Menlo Park, CA 94025 USA.
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Ishikawa O, Hahn S, Greenberg H. Pharmacologic Therapy for Narcolepsy. Neurology 2022. [DOI: 10.17925/usn.2022.18.1.68] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Narcolepsy is a lifelong disorder that adversely affects daytime function and quality of life. Major symptoms include excessive daytime sleepiness with irrepressible sleep attacks and cataplexy. Recent developments in the understanding of the pathobiology of narcolepsy, as well as the neuronal systems involved in the regulation of wakefulness have led to development of new pharmacologic approaches to therapy. In this paper, we review available pharmacologic treatments for narcolepsy as well as agents currently under investigation.
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Dauvilliers Y, Bogan RK, Šonka K, Partinen M, Foldvary-Schaefer N, Thorpy MJ. Calcium, Magnesium, Potassium, and Sodium Oxybates Oral Solution: A Lower-Sodium Alternative for Cataplexy or Excessive Daytime Sleepiness Associated with Narcolepsy. Nat Sci Sleep 2022; 14:531-546. [PMID: 35378745 PMCID: PMC8976528 DOI: 10.2147/nss.s279345] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Accepted: 03/08/2022] [Indexed: 11/23/2022] Open
Abstract
Lower-sodium oxybate (LXB) is an oxybate medication approved to treat cataplexy or excessive daytime sleepiness (EDS) in patients with narcolepsy 7 years of age and older in the United States. LXB was developed as an alternative to sodium oxybate (SXB), because the incidence of cardiovascular comorbidities is higher in patients with narcolepsy and there is an elevated cardiovascular risk associated with high sodium consumption. LXB has a unique formulation of calcium, magnesium, potassium, and sodium ions, containing 92% less sodium than SXB. Whereas the active oxybate moiety is the same for LXB and SXB, their pharmacokinetic profiles are not bioequivalent; therefore, a phase 3 trial in participants with narcolepsy was conducted for LXB. This review summarizes the background on oxybate as a therapeutic agent and its potential mechanism of action on the gamma-aminobutyric acid type B (GABAB) receptor at noradrenergic and dopaminergic neurons, as well as at thalamocortical neurons. The rationale leading to the development of LXB as a lower-sodium alternative to SXB and the key efficacy and safety data supporting its approval for both adult and pediatric patients with narcolepsy are also discussed. LXB was approved in August 2021 in the United States for the treatment of idiopathic hypersomnia in adults. Potential future developments in the field of oxybate medications may include novel formulations and expanded indications for other diseases.
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Affiliation(s)
- Yves Dauvilliers
- Sleep and Wake Disorders Centre, Department of Neurology, Gui de Chauliac Hospital, Montpellier, France.,University of Montpellier, INSERM Institute Neuroscience Montpellier (INM), Montpellier, France
| | - Richard K Bogan
- University of South Carolina School of Medicine, Columbia, SC, USA
| | - Karel Šonka
- Department of Neurology, First Faculty of Medicine, Charles University and General University Hospital, Prague, Czech Republic
| | - Markku Partinen
- Helsinki Sleep Clinic, Terveystalo Healthcare, and Department of Clinical Neurosciences, University of Helsinki, Helsinki, Finland
| | | | - Michael J Thorpy
- Department of Neurology, Albert Einstein College of Medicine, Bronx, NY, USA
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Vringer M, Kornum BR. Emerging therapeutic targets for narcolepsy. Expert Opin Ther Targets 2021; 25:559-572. [PMID: 34402358 DOI: 10.1080/14728222.2021.1969361] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Accepted: 08/13/2021] [Indexed: 01/02/2023]
Abstract
INTRODUCTION Narcolepsy type 1 (NT1) and type 2 (NT2) are chronic sleep disorders primarily characterized by excessive daytime sleepiness (EDS), disturbed sleep-wake regulation, and reduced quality of life. The precise disease mechanism is unclear, but it is certain that in NT1 the hypocretin/orexin (Hcrt) system is affected. Current treatment options are symptomatic - they improve EDS and/or reduce cataplexy. Complete symptom control is relatively rare - particularly problematic is residual daytime sleepiness. AREAS COVERED This review discusses various emerging treatment targets for narcolepsy. The focus is on the Hcrt receptors but included are also wake-promoting pathways, and sleep-stabilization through GABAergic mechanisms. Additionally, we discuss the potential of targeting the likely autoimmune basis of narcolepsy. PubMed and ClinicalTrials.gov was searched through June 2021 for relevant information. EXPERT OPINION Targeting Hcrt receptors has the potential to alleviate narcolepsy symptoms. Results from ongoing drug development programs are promising, but care needs to be taken when evaluating potential side effects. It is still largely unknown what roles Hcrt receptors play in the periphery and how these might be affected by treatment. Immunotherapies could potentially target the core pathophysiology of narcolepsy, but more work is needed to identify the best therapeutic target for this approach.
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Affiliation(s)
- Marieke Vringer
- Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Department of Psychiatry and Neuropsychology, School of Mental Health and Neuroscience (Mhens), Maastricht University, Maastricht, Netherlands
| | - Birgitte Rahbek Kornum
- Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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XU Q, LOU G, WANG T, ZHANG L. [Advances in treatment of narcolepsy]. Zhejiang Da Xue Xue Bao Yi Xue Ban 2020; 49:419-424. [PMID: 32985153 PMCID: PMC8800692 DOI: 10.3785/j.issn.1008-9292.2020.08.17] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Accepted: 08/10/2020] [Indexed: 06/11/2023]
Abstract
Narcolepsy is the most common cause of excessive daytime sleepiness (EDS) following obstructive sleep apnea. Its treatment aims to reduce EDS and cataplexy, improve nighttime sleep disturbance, sleep paralysis and sleep-related hallucinations. Pitolisant (a histamine H3 receptor antagonist) and solriamfetol (a norepinephrine reuptake inhibitor) have recently been approved effective for narcolepsy in the United States and the European Union. Pitolisant has proved to be effective for both EDS and cataplexy. Besides being effective on EDS, solriamfetol seems to have advantages in abuse potential and withdrawal syndrome. As potential treatments for EDS and cataplexy associated with narcolepsy, several new drugs are being developed and tested. These new drugs include new hydroxybutyrate preparations (controlled release sodium hydroxybutyrate FT218, low sodium hydroxybutyrate JZP-258), selective norepinephrine reuptake inhibitor (AXS-12), and modafinil combined with astroglial junction protein inhibitor (THN102). This paper reviews the recently approved drugs and potential treatments for narcolepsy.
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Affiliation(s)
| | | | | | - Lisan ZHANG
- 张力三(1977-), 男, 博士, 主任医师, 硕士生导师, 主要从事神经病学和睡眠医学研究; E-mail:
;
https://orcid.org/0000-0002-3774-9926
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Barker EC, Flygare J, Paruthi S, Sharkey KM. Living with Narcolepsy: Current Management Strategies, Future Prospects, and Overlooked Real-Life Concerns. Nat Sci Sleep 2020; 12:453-466. [PMID: 32765142 PMCID: PMC7371435 DOI: 10.2147/nss.s162762] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Accepted: 06/17/2020] [Indexed: 12/21/2022] Open
Abstract
Narcolepsy is a neurological disorder of the sleep-wake cycle characterized by excessive daytime sleepiness (EDS), cataplexy, nighttime sleep disturbances, and REM-sleep-related phenomena (sleep paralysis, hallucinations) that intrude into wakefulness. Dysfunction of the hypocretin/orexin system has been implicated as the underlying cause of narcolepsy with cataplexy. In most people with narcolepsy, symptom onset occurs between the ages of 10 and 35 years, but because the disorder is underrecognized and testing is complex, delays in diagnosis and treatment are common. Narcolepsy is treated with a combination of lifestyle modifications and medications that promote wakefulness and suppress cataplexy. Treatments are often effective in improving daytime functioning for individuals with narcolepsy, but side effects and/or lack of efficacy can result in suboptimal management of symptoms and, in many cases, significant residual impairment. Additionally, the psychosocial ramifications of narcolepsy are often neglected. Recently two new pharmacologic treatment options, solriamfetol and pitolisant, have been approved for adults, and the indication for sodium oxybate in narcolepsy has been expanded to include children. In recent years, there has been an uptick in patient-centered research, and promising new diagnostic and therapeutic options are in development. This paper summarizes current and prospective pharmacological therapies for treating both EDS and cataplexy, discusses concerns specific to children and reproductive-age women with narcolepsy, and reviews the negative impact of health-related stigma and efforts to address narcolepsy stigma.
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Affiliation(s)
- Emily C Barker
- Case Western Reserve University School of Medicine, Department of Pediatrics, Cleveland, OH, USA
| | | | - Shalini Paruthi
- Sleep Medicine and Research Center, St. Luke’s Hospital, St. Louis, MO, USA
- Saint Louis University School of Medicine, Departments of Medicine and Pediatrics, St. Louis, MO, USA
| | - Katherine M Sharkey
- Department of Medicine, The Warren Alpert Medical School of Brown University, Providence, RI, USA
- Department of Psychiatry & Human Behavior, The Warren Alpert Medical School of Brown University, Providence, RI, USA
- Rhode Island Hospital, Providence, RI, USA
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Peyron C, Arthaud S, Villalba M, Fort P. Defining and measuring paradoxical (REM) sleep in animal models of sleep disorders. CURRENT OPINION IN PHYSIOLOGY 2020. [DOI: 10.1016/j.cophys.2020.03.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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10
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Abstract
Narcolepsy is a chronic, disabling neurologic disorder characterised by excessive daytime sleepiness (EDS) and, in up to 60% of patients, cataplexy. Treatments for narcolepsy are aimed at improving wakefulness (e.g. modafinil, armodafinil, stimulants), reducing cataplexy attacks (e.g. sodium oxybate, venlafaxine), and treating the symptoms of disturbed nocturnal sleep, sleep paralysis and sleep-related hallucinations (e.g. sodium oxybate). In general, medications that increase the release, or inhibit the reuptake, of norepinephrine or dopamine have wake-promoting effects and are useful in managing EDS, whereas medications that inhibit serotonin or norepinephrine reuptake have anticataplectic effects. Modulation of γ-aminobutyric acid B (GABAB) receptors or histamine H3 receptors (H3Rs) has effects on both EDS and cataplexy. Pitolisant, an H3R antagonist, and solriamfetol, a dopamine and norepinephrine reuptake inhibitor, are the most recently approved treatments for EDS associated with narcolepsy in the European Union (pitolisant) and the USA (pitolisant and solriamfetol). Several new agents are being developed and tested as potential treatments for EDS and cataplexy associated with narcolepsy; these agents include novel oxybate formulations (once-nightly [FT218]; low sodium [JZP-258]), a selective norepinephrine reuptake inhibitor (AXS-12), and a product combining modafinil and an astroglial connexin inhibitor (THN102). This review summarises the mechanisms of action, pharmacokinetics, efficacy, and safety/tolerability of recently approved and emerging treatments for narcolepsy.
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Affiliation(s)
- Michael J Thorpy
- Sleep-Wake Disorders Center, Montefiore Medical Center, 111 East 210th Street, Bronx, NY, 10467-2509, USA.
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Pillen S, Pizza F, Dhondt K, Scammell TE, Overeem S. Cataplexy and Its Mimics: Clinical Recognition and Management. Curr Treat Options Neurol 2017; 19:23. [PMID: 28478511 DOI: 10.1007/s11940-017-0459-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
OPINION STATEMENT This review describes the diagnosis and management of cataplexy: attacks of bilateral loss of muscle tone, triggered by emotions and with preserved consciousness. Although cataplexy is rare, its recognition is important as in most cases, it leads to a diagnosis of narcolepsy, a disorder that still takes a median of 9 years to be diagnosed. The expression of cataplexy varies widely, from partial episodes affecting only the neck muscles to generalized attacks leading to falls. Moreover, childhood cataplexy differs from the presentation in adults, with a prominent facial involvement, already evident without clear emotional triggers ('cataplectic facies') and 'active' motor phenomena especially of the tongue and perioral muscles. Next to narcolepsy, cataplexy can sometimes be caused by other diseases, such as Niemann-Pick type C, Prader Willi Syndrome, or lesions in the hypothalamic or pontomedullary region. Cataplexy mimics include syncope, epilepsy, hyperekplexia, drop attacks and pseudocataplexy. They can be differentiated from cataplexy using thorough history taking, supplemented with (home)video recordings whenever possible. Childhood narcolepsy, with its profound facial hypotonia, can be confused with neuromuscular disorders, and the active motor phenomenona resemble those found in childhood movement disorders such as Sydenham's chorea. Currently, the diagnosis of cataplexy is made almost solely on clinical grounds, based on history taking and (home) videos. Cataplexy shows remarkable differences in childhood compared to adults, with profound facial hypotonia and complex active motor phenomena. Over time, these severe symptoms evolve to the milder adult phenotype, and this pattern is crucial to recognize when assessing the outcome of uncontrolled case series with potential treatments such as immunomodulation. Symptomatic treatment is possible with antidepressants and sodium oxybate. Importantly, management also needs to involve sleep hygiene advice, safety measures whenever applicable and guidance with regard to the social sequelae of cataplexy.
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Affiliation(s)
- Sigrid Pillen
- Sleep Medicine Center Kempenhaeghe, P.O. Box 61, , 5590 AB, Heeze, The Netherlands.
| | - Fabio Pizza
- Department of Biomedical and Neuromotor Sciences (DIBINEM), University of Bologna, Bologna, Italy.,IRCCS Institute of the Neurological SciencesAUSL di Bologna, Bologna, Italy
| | - Karlien Dhondt
- Department Pediatrics, Division of Child Neurology & Metabolism, Pediatric Sleep Center, Ghent University Hospital, Ghent, Belgium
| | - Thomas E Scammell
- Department of Neurology, Beth Israel Deaconess Medical Center, Boston Children's Hospital, Boston, MA, USA
| | - Sebastiaan Overeem
- Sleep Medicine Center Kempenhaeghe, P.O. Box 61, , 5590 AB, Heeze, The Netherlands.,Eindhoven University of Technology, Eindhoven, The Netherlands
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