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Objectives: The patho-aetiology of narcolepsy Type I (NT1) is the loss of hypocretin-1 secreting neurons in the hypothalamus. Diagnostic criteria for NT1 include excessive daytime sleepiness (EDS) for at least three months not explained by any other condition, cataplexy and cerebrospinal fluid (CSF) hypocretin-1 concentrations lower than 110 pg/ml. In this study we evaluated the utility of measuring CSF hypocretin-1 levels in patients with suspected narcolepsy (N)., Methods: The study included 29 consecutively recruited patients at a tertiary sleep centre presenting with EDS for exclusion of N. All patients were examined using an extensive clinical interview followed by two weeks of actigraphy and sleep diary recordings, polysomnography (PSG) and multiple sleep latency testing (MSLT). Additionally, HLA-typing, urinary screening for substances of abuse and a lumbar puncture to measure CSF hypocretin-1 expression using radioimmunoassay were carried out., Results: In sum, 19 patients (66%) had a CSF hypocretin-1 level <110 pg/ml, of whom two had current severe depression without any features of narcolepsy except EDS. The predictive potential of hypocretin-1 measurement in diagnosing narcolepsy revealed a positive predictive value (PPV) of 89%, a specificity of 83%, with both negative predictive value (NPV) and sensitivity equal to 100%., Conclusions: Despite a high sensitivity and specificity, the MSLT is not always a reliable diagnostic test for narcolepsy and where this uncertainty exits, CSF hypocretin-1 concentrations <110 pg/ml can be useful. However, due to a lower PPV and specificity at this cut-off, it may also not be entirely reliable as a stand-alone diagnostic test, particularly in the context of severe depression., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Background: Narcolepsy is a chronic primary sleep disorder, characterized by excessive daytime sleepiness and sleep dysfunction with or without cataplexy. Narcolepsy is uncommon, with a low prevalence rate which makes it difficult to diagnose definitively without a complex series of tests and a detailed history. The aim of this study was to review patients referred to a tertiary sleep centre who had been labelled with a diagnosis of narcolepsy prior to referral in order to assess if the diagnosis was accurate, and if not, to determine the cause of diagnostic misattribution., Methods: All patients seen at a sleep centre from 2007-2013 (n = 551) who underwent detailed objective testing including an MSLT PSG, as well as wearing an actigraphy watch and completing a sleep diary for 2 weeks, were assessed for a pre-referral and final diagnosis of narcolepsy., Results: Of the 41 directly referred patients with a diagnostic label of narcolepsy, 19 (46 %) were subsequently confirmed to have narcolepsy on objective testing and assessment by a sleep physician using ICSD-2 criteria., Conclusions: The diagnosis of narcolepsy was incorrectly attributed to almost 50 % of patients labelled with a diagnosis of narcolepsy who were referred for further opinion by a variety of specialists and generalists. Accurate diagnosis of narcolepsy is critical for many reasons, such as the impact it has on quality of life, driving, employment, insurance and pregnancy in women as well as medication management., Competing Interests: Compliance with ethical standards Funding No funding was received for this research. Conflict of interest All authors certify that they have no affiliations or involvement with any organization or entity with any financial interest (such as honoraria; educational grants; participation in speakers’ bureaus; membership, employment, consultancies, stock ownership or other equity interest; and exert testimony or patent-licensing arrangements) or non-financial interest (such as personal or professional relationships, affiliations, knowledge or beliefs) in the subject matter or materials discussed in this manuscript. Ethical approval All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. Informed consent This study does not have any informed consent. Authors’ contributions Laura Dunne did the writing, analysis and primary data collection. Pallavi Patel and Emily L Maschauer did the writing and editing. Ian Morrison did the writing, editing and design. Renata Riha did the design, analysis, writing and editing. Disclosures Laura Dunne, Pallavi Patel, Emily L Maschauer, Ian Morrison and Renata Riha report no disclosures with respect to this study.

In a retrospective cohort study undertaken in 12 European countries, 249 female narcoleptic patients with cataplexy (n = 216) and without cataplexy (n = 33) completed a self-administrated questionnaire regarding pregnancy and childbirth. The cohort was divided further into patients whose symptoms of narcolepsy started before or during pregnancy (308 pregnancies) and those in whom the first symptoms of narcolepsy appeared after delivery (106 pregnancies). Patients with narcolepsy during pregnancy were older during their first pregnancy (P < 0.001) and had a higher body mass index (BMI) prior to pregnancy (P < 0.01). Weight gain during pregnancy was higher in narcoleptic patients with cataplexy (P < 0.01). More patients with narcolepsy-cataplexy during pregnancy had impaired glucose metabolism and anaemia. Three patients experienced cataplexy during delivery. The rate of caesarean sections was higher in the narcolepsy-cataplexy group compared to the narcolepsy group (P < 0.05). The mean birth weight and gestational age of neonates were within the normal range and did not differ across groups. Neonatal care was affected adversely by symptoms of narcolepsy in 60.1% of those with narcolepsy during pregnancy. This study reports more obstetric complications in patients with narcolepsy-cataplexy during pregnancy; however, these were not severe. This group also had a higher BMI and higher incidence of impaired glucose metabolism during pregnancy. Caesarian section was conducted more frequently in narcolepsy-cataplexy patients, despite cataplexy being a rare event during delivery. Furthermore, symptoms of narcolepsy may render care of the infant more difficult., (© 2013 European Sleep Research Society.)

Unlabelled: Guidelines for the multiple sleep latency test (MSLT) were published in 1986 and updated in 2005. Individual interpretation of instructions may lead to variability in conducting and reporting the test with implications for diagnosis., Objective: To assess variability in conducting MSLT among sleep laboratories in Europe., Methods: A questionnaire based on the clinical MSLT guidelines was posted or emailed to 283 sleep centres in Europe., Results: Ninety adult laboratories performing MSLT returned the questionnaire. Indications for MSLT were: narcolepsy, excessive daytime somnolence, driving issues and assessment of wakefulness. Routinely, only 17% of laboratories performed urinary drug screening and 68.2% asked patients to complete sleep diaries. Overnight polysomnography before MSLT was ran in 87.5% of laboratories. There was variation in setup and instructions among countries. Sleep onset was scored as one epoch of any stage sleep by 65.9% of labs. REM latency was calculated and reported according to the 2005 guidelines in 73.7% of cases. Abnormal daytime sleepiness was considered to be a sleep latency⩽5min in 33% laboratories., Conclusion: There is marked variability in the practice and interpretation of the MSLT in Europe., (Copyright © 2012 Elsevier B.V. All rights reserved.)

Background and Purpose: There is a high incidence of sleep-disordered breathing (SDB) in narcoleptic patients. Some narcoleptics with SDB may benefit from treatment with continuous positive airway pressure therapy (CPAP). The aim of this study was to examine the prevalence of SDB in narcoleptics referred to a tertiary sleep disorders clinic and assess the effectiveness of CPAP as adjunctive therapy., Methods: A retrospective review of patients meeting ICSD-2 criteria for the diagnosis of narcolepsy from 2000 to 2009., Results:   One hundred and two patients (61 women) with narcolepsy were included in the study. Twenty-nine (29) patients (eight women, 21 men) were diagnosed with obstructive sleep apnoea-hypopnoea syndrome (OSAHS) of whom 26 commenced CPAP therapy with 11 patients concurrently treated with stimulants. Patients with narcolepsy and OSAHS were older (P = 0.009) and heavier (BMI, 29.6 ± 4.8 vs. 27.3 ± 6, P = 0.042), but their ESS did not differ from patients with narcolepsy alone. Patients treated with both CPAP and stimulants were younger (P = 0.008) and less obese (BMI, 29.1 ± 4.6 vs. 30.4 ± 5.4, P = 0.044) with higher apnoea-hypopnoea index (36.15 ± 21.9 vs. 31.5 ± 16.7, P = 0.03) than those treated with CPAP alone. The ESS of CPAP-treated patients improved during follow-up (19 ± 3.6 vs. 15.8 ± 4.5, P = 0.006), but BMI increased (30.6 ± 5 vs. 31.7 ± 5.6, P = 0.05). The use of stimulants did not seem to improve on the effectiveness of CPAP., Conclusion:   Coexisting SDB is common in narcoleptics (28.5%). CPAP therapy in narcoleptics with OSAHS remains a useful second-line adjunct to standard therapy., (© 2011 The Author(s). European Journal of Neurology © 2011 EFNS.)

Background and Purpose: The second version of the International Classification of Sleep Disorders suggests narcolepsy with cataplexy can be diagnosed on history alone., Patients: Five patients with a history supportive of narcolepsy/cataplexy., Method: Case review following clinical investigation., Results: None of the five patients had a diagnosis of narcolepsy/cataplexy on the basis of objective testing using polysomnography (PSG) and multiple sleep latency testing (MSLT)., Conclusion: PSG and MSLT should always be used in conjunction with a comprehensive history taken by an experienced sleep physician to support a diagnosis of narcolepsy with cataplexy and to exclude other conditions that may mimic narcolepsy., (© 2010 The Author(s). European Journal of Neurology © 2010 EFNS.)