The epidemiology of narcolepsy

Healthcare Burden and Productivity Loss Due to Narcolepsy in Sweden

BACKGROUND

Narcolepsy impacts both patients and society, yet there is limited data on its socioeconomic consequences.

METHODS

This retrospective longitudinal cohort study used pseudonymized patient-level data from Swedish registers and included narcolepsy patients from January 2015-December 2019 and age-sex matched controls. All patients received an index date corresponding to their first narcolepsy diagnosis.

RESULTS

This study included 466 incident narcolepsy patients and 2330 matched controls. During the years studied, healthcare resource utilization was 2-5 times higher for incident narcolepsy patients compared to matched controls (p < 0.0001). Modafinil, stimulants, and antidepressants were prescribed more often to incident narcolepsy patients (p < 0.0001). Work productivity was significantly impacted, as incident narcolepsy patients took 7.0-10.5 more sick leave days than their matched controls (p < 0.0001) and had an average of 14.8 net days of disability leave (associated with indirect costs of EUR 1630) versus only 5.8 days among matched controls (EUR 638) during the year of the index (p = 0.027). After controlling for age, sex, and the Charlson comorbidity index, the odds of disability leave were 3.3 times higher in incident narcolepsy patients.

CONCLUSIONS

This study provides evidence of the magnitude of the substantial societal economic burden due to narcolepsy in Sweden, evidenced by higher healthcare resource utilization and indirect costs.

Narcolepsy as a potential risk factor for Schizophrenia

Narcolepsy is a severe sleep disorder with characteristics of fatigue, fragmented sleep, cataplexy and hypnagogic hallucinations. Earlier clinical studies have reported the onset of schizophrenia after narcolepsy but the causality behind narcolepsy and schizophrenia is unknown. Our goal was to understand the causality between narcolepsy and schizophrenia. To estimate the comorbidity between narcolepsy and schizophrenia, we employed data from the FinRegistry that contains data for the total population of Finland in total 7.2 million individuals (N = 1664 individuals with narcolepsy and 55,372 with schizophrenia). We then used Mendelian randomization and previously published genome-wide association data to test the causality between narcolepsy and schizophrenia. We observed a robust causal association from narcolepsy to schizophrenia using the HLA-independent lead variants (P-value = 6.0 × 10-4), which was accentuated when including the HLA locus (P-value = 4.48 × 10-7). Furthermore, we observed a modest bidirectional causality from schizophrenia to narcolepsy (P-value = 0.015). There was no evidence of pleiotropy. Our findings indicate a causal relationship where narcolepsy may increase the risk for schizophrenia, and a bidirectional causality from schizophrenia to narcolepsy. Additionally, our results clarify the psychiatric burden in narcolepsy.

White matter changes in patients with narcolepsy type 2: Peak width of skeletonized mean diffusivity study

OBJECTIVES

This study aimed to investigate white matter (WM) microstructural alterations in patients with narcolepsy type 2 (NT2) using Peak Width of Skeletonized Mean Diffusivity (PSMD), a novel imaging marker associated with small vessel disease (SVD). The study compared PSMD metrics between patients with NT2 and healthy controls to investigate structural disruptions and their implications for NT2 pathophysiology.

METHODS

A total of 42 participants were enrolled, including 20 patients with newly diagnosed NT2 and 22 healthy controls. Diffusion tensor imaging (DTI) was performed using a 3 T MRI scanner. PSMD was calculated using a multi-step process involving preprocessing, skeletonization, application of a custom mask, and histogram analysis with the FSL program. PSMD values were compared between patients with NT2 and healthy controls, and correlation analyses were conducted to examine associations between PSMD and clinical variables.

RESULTS

Patients with NT2 exhibited significantly higher PSMD compared to healthy controls (2.172 × 10-4 mm2/s vs. 2.031 × 10-4 mm2/s, p = 0.011). PSMD also positively correlated with age in both patients with NT2 (r = 0.608, p = 0.004) and healthy controls (r = 0.696, p < 0.001).

CONCLUSION

Patients with NT2 demonstrate increased PSMD, indicating WM microstructural changes potentially linked to SVD. These findings highlight the utility of PSMD as a sensitive neuroimaging marker for detecting WM alterations in sleep disorders. Further studies are needed to validate these results and investigate the underlying mechanisms of WM changes in NT2.

Epidemiology, patient characteristics, and treatment patterns of patients with narcolepsy in Sweden: a non-interventional study using secondary data

Study Objectives

To estimate the prevalence and incidence and evaluate the treatment patterns of patients diagnosed with narcolepsy in specialist care in Sweden.

Methods

This non-interventional retrospective longitudinal study used Swedish register data from 2010 to 2020 and included patients diagnosed with narcolepsy (either type 1 or type 2), recorded in specialist outpatient and inpatient care from January 2015 to December 2019. All patients received an index date corresponding to the date of the first narcolepsy diagnosis.

Results

The prevalence and incidence of narcolepsy were 14.7/100 000 and 0.9/100 000 individuals, respectively, with a greater proportion of females than males. The study included 1846 prevalent narcolepsy patients of either type, of which 466 were incident. The majority of prevalent patients (87.9%) were prescribed narcolepsy-related treatment at index with stimulants being the most common treatment. Both in the years before and after index, the most used medication by prevalent patients was stimulants (42.4% and 54.8%, respectively). Among incident patients, stimulants were the most common drug in the year after index (57.0%). Treatment switching following index was frequent and a large share of incident patients who started on modafinil were switched to stimulants.

Conclusions

The prevalence of narcolepsy was lower than previously reported and was higher in females than in males; incidence was comparable throughout the study period. At index, not all patients used narcolepsy-related medications, potentially indicating a hesitance towards treatment and/or a need for faster initiation of treatment following index. Many patients were switched from the treatment they first initiated after diagnosis, which might be due to a lack of efficacy and/or unacceptable side effects.

Alterations in the DTI-ALPS index and choroid plexus volume are associated with clinical symptoms in participants with narcolepsy type 1

BACKGROUND

Narcolepsy type 1 (NT1) is a sleep disorder characterized by excessive daytime sleepiness accompanied by cataplexy. Sleep disorders have been shown to affect the glymphatic system. This study aimed to evaluate changes in the diffusion tensor imaging along the perivascular space (DTI-ALPS) index and choroid plexus (CP) volume in NT1 participants, and to further explore their clinical significance.

METHODS

We prospectively enrolled participants diagnosed with NT1 based on cerebrospinal fluid hypocretin-1 concentration and multiple sleep latency tests at our hospital. All participants underwent MRI to allow analysis of the DTI-ALPS index and CP volume. We subsequently performed correlation analyses between the DTI-ALPS index, CP volume, and important clinical parameters, including the Epworth Sleepiness Scale (ESS) score, Narcolepsy Severity Scale (NSS) score, stage rapid eye movement sleep (REM) ratio, stage 1 non-REM (N1) ratio, stage 2 non-REM (N2) ratio, and stage 3 non-REM (N3) ratio, among the NT1 participants. Inter-group and correlation analyses of DTI-ALPS index and CP volume were performed using age, sex, body mass index, and lateral ventricle volume as covariates.

RESULTS

This study enrolled 41 NT1 participants and 42 healthy controls (HC). The DTI-ALPS index of NT1 participants was significantly lower than HC (1.444 ± 0.119 vs.1.661 ± 0.135, P < 0.001), while the CP volume of NT1 participants was significantly larger than those of HC (0.831 ± 0.146 vs. 0.645 ± 0.137, P < 0.001). The DTI-ALPS index was negatively correlated with both the ESS (PFDR-corrected<0.001) and NSS scores (PFDR-corrected = 0.010), but positively correlated with the Stage N3 ratio (PFDR-corrected = 0.033). The CP volume of NT1 participants was positively correlated with ESS (PFDR-corrected = 0.047) and NSS scores (PFDR-corrected = 0.047), but negatively correlated with the stage N3 ratio (PFDR-corrected = 0.047).

CONCLUSION

Our study suggests that the DTI-ALPS index was lower and CP volume was larger in NT1 participants. The DTI-ALPS index and CP volume in the NT1 participants were related to disease severity and sleep structure. These findings may provide new insights into the mechanisms underlying NT1.

Armodafinil as Monotherapy in Treating Narcolepsy with Cataplexy

In narcolepsy with cataplexy, sodium oxybate and the recently FDA-approved drug pitolisant are preferred medications. Armodafinil, a longer-acting, non-amphetamine stimulant, is often used in patients who have narcolepsy without cataplexy. It enhances alertness by increasing presynaptic dopamine transmission presynaptically, amplifying serotonin in the cerebral cortex, activating glutamatergic circuits, which may contribute to its vigilance-enhancing properties, and stimulating orexin activity. Armodafinil alone is approved for excessive daytime sleepiness (EDS) symptoms. We report this case of narcolepsy with cataplexy, where armodafinil alone improved the symptoms of not only EDS but also cataplexy. It is known that sodium oxybate, through its gamma-aminobutyric acid type B (GABA-B) receptor agonist activity, helps in cataplexy and EDS. However, in some instances, like this patient, armodafinil alone improves the symptoms of cataplexy and maintains wakefulness.

Cataplexy response with extended-release once-nightly sodium oxybate: Post hoc responder analyses from the phase 3 REST-ON clinical trial

Background

Once-nightly sodium oxybate (ON-SXB), an extended-release oxybate formulation, yielded significant (P < 0.001 at 6 g, 7.5 g, and 9 g) reductions in cataplexy episodes in participants in the phase 3 REST-ON clinical trial (NCT02720744). This post hoc analysis from REST-ON further characterized changes in cataplexy episodes in participants with narcolepsy type 1 (NT1).

Methods

Participants with narcolepsy aged ≥16 years received ON-SXB (1 wk, 4.5 g; 2 wk, 6 g; 5 wk, 7.5 g; 5 wk, 9 g) or placebo. Percentages of participants with NT1 who had ≥25%, ≥50%, ≥75%, and 100% reductions from baseline in mean number of weekly cataplexy episodes were determined. Two-sided P values comparing ON-SXB vs placebo were calculated with Fisher exact test.

Results

Participants with NT1 (ON-SXB, n = 73; placebo, n = 72; modified intent-to-treat population) had a baseline mean number of weekly cataplexy episodes of 18.9 (ON-SXB) and 19.8 (placebo). Of participants receiving the highest doses of ON-SXB (7.5 and 9 g), approximately half had a 50% reduction, one-third had a 75% reduction, and one-tenth had a 100% reduction in their cataplexy episodes vs placebo. Significantly greater proportions of participants receiving ON-SXB vs placebo had respective reductions in weekly cataplexy episodes of ≥25% at weeks 1 (4.5 g; P < 0.05), 3 (6 g; P < 0.001), 8 (7.5 g; P < 0.001), and 13 (9 g; P = 0.001).

Conclusions

A significantly greater proportion of participants receiving ON-SXB vs placebo experienced reductions in weekly cataplexy episodes at all tested doses. Approximately 10% of participants taking the 2 highest ON-SXB doses had complete elimination of their cataplexy.

Improvement in sleep latency with extended-release once-nightly sodium oxybate for the treatment of adults with narcolepsy: Analysis from the phase 3 REST-ON clinical trial

Background

In the REST-ON clinical trial (NCT02720744), mean sleep latency on the Maintenance of Wakefulness Test (MWT) was significantly improved with extended-release once-nightly sodium oxybate (ON-SXB) vs placebo (P < 0.001) in participants with narcolepsy. This post hoc analysis assessed response to treatment and improvement in excessive daytime sleepiness.

Methods

Participants with narcolepsy aged ≥16 years were randomized 1:1 to receive ON-SXB (4.5 g, week 1; 6 g, weeks 2-3; 7.5 g, weeks 3-8; and 9 g, weeks 9-13) or placebo. Mean sleep latency on the MWT was measured across 5 trials of ≤30 min each. Post hoc assessments included percentage of participants whose sleep latency improved ≥5, ≥10, ≥15, and ≥20 min and with a mean sleep latency of 30 min.

Results

Significantly more participants receiving ON-SXB vs placebo experienced increased mean sleep latency ≥5 min (all doses P < 0.001), ≥10 min (all doses P < 0.001), ≥15 min (6 and 7.5 g, P < 0.001; 9 g, P < 0.01), and ≥20 min (6 g, P < 0.01; 7.5 g, P < 0.001; 9 g, P < 0.05). More participants receiving ON-SXB had mean sleep latency of 30 min vs placebo (6 g, 5.7 % vs 0 %, respectively [P < 0.05]; 7.5 g, 10.5 % vs 1.3 % [P < 0.05]; 9 g, 13.2 % vs 5.1 % [P = 0.143]).

Conclusions

Significantly more participants who received ON-SXB experienced increased mean sleep latency ≥5 to ≥20 min; at the 2 highest doses, >10 % remained awake for the entirety of the MWT. ON-SXB offers a once-at-bedtime treatment option for adults with narcolepsy.

Understanding the Patient Experience with Twice-Nightly Sodium Oxybate Therapy for Narcolepsy: A Social Listening Experiment

BACKGROUND/OBJECTIVES

Narcolepsy is a chronic neurologic disorder associated with substantial challenges that affect the social, emotional, and financial quality-of-life domains. A social listening analysis and structured survey were conducted to better understand the candid perspective of people with narcolepsy (PWN) and their experience with twice-nightly sodium oxybate (SXB).

METHODS

To characterize conversations and experiences in narcolepsy communities where SXB was mentioned, a social media analysis was conducted from August 2011 to October 2022. A structured survey was administered to PWN taking oxybate therapy from October 2022 to November 2022.

RESULTS

From the social media analysis, the largest topic was related to "cataplexy", with 537 posts/comments. The most frequent term was "xyrem", with 22,200 mentions. Of the 87 survey respondents, 85 respondents had narcolepsy, 75.3% (64/85) reported missing their second dose of immediate-release SXB or mixed-salt oxybates, and 58.8% (50/85) of respondents reported that they took their second dose of oxybate > 4 h after the first dose. Respondents reported poor sleep quality as the greatest effect or issue experienced after missing their second oxybate dose. When respondents were asked whether they had ever been injured after waking to take their second oxybate dose, 31.8% (27/85) of respondents reported an injury.

CONCLUSIONS

PWN taking twice-nightly oxybates often report inconsistent adherence to the prescribed dosing, which results in negative consequences in their lives. This research provided an anonymized forum for PWN to voice challenges with middle-of-the-night awakenings that they may be reluctant to explain to their clinician.

Patient experiences of narcolepsy and idiopathic hypersomnia in the Nordics: a patient journey map

Central disorders of hypersomnolence (CDH) are chronic diseases that significantly impact the lives of affected individuals. We aimed to explore the perspectives of individuals with narcolepsy type 1 (NT1), narcolepsy type 2 (NT2), and idiopathic hypersomnia (IH), and the challenges they encounter in their daily lives and within the healthcare systems in the Nordics. Interviews with patients (N = 41) and healthcare professionals (n = 14) and a patient survey (n = 70) were conducted in 2022 in Denmark, Sweden, Finland, and Norway to develop a patient journey map that visualises the patient with CDH journey and provides insights into the difficulties faced by these individuals. The patient journey mapping approach was chosen to focus on the processes and experiences of patients, highlighting the challenges they confront. Our findings revealed that the process of receiving a CDH diagnosis, as well as subsequent misdiagnoses and treatment, can be protracted and burdensome. CDH diagnoses remain poorly understood by neurologists, general practitioners, and the public, resulting in adverse consequences, with patients reporting a mean (standard deviation [SD]) time from symptom onset to diagnosis of 8.4 (5.11) years and a mean (SD) of 5.5 (4.17) productive hours lost/day. The available non-pharmaceutical support for patients with CDH, encompassing medical, psychological, educational, and professional assistance, was insufficient. The generalisability of the findings to one specific diagnosis is limited due to the collective analysis of the CDH. These findings are invaluable for identifying disruptions in the patient with CDH journeys and for designing improved pathways for those with NT1, NT2, and IH in the future.

Exploring the emotional and behavioural profile in paediatric narcolepsy type 1: A case-control study

Narcolepsy type 1 (NT1) is a central disorder of hypersomnolence often arising in childhood and adolescence. NT1 has a significant, but poorly defined, psychological impact. We aimed to investigate the psycho-social functioning of children and adolescents with NT1. We performed a cross-sectional, child and parent-reported questionnaire survey in 37 children and adolescents (6-17 years) with NT1, compared with age- and sex-matched controls. Questionnaires (SSHS, ESS-CHAD, CDI, MASC, CBCL, CRS-R, and SNAP-IV) evaluated various aspects of behavioural and emotional profiles, sleep habits, and daytime sleepiness. Subsequently, NT1 intra-group analysis was performed to investigate the effect of sex (males vs females) and pharmacological treatment (treated vs non-treated) on psychological features. The NT1 questionnaires total scores were then correlated with the clinical characteristics (age, body mass index [BMI], ESS-CHAD score, cerebrospinal hypocretin-1 [Hcrt-1] levels, and diagnostic delay). Patients with NT1 showed a higher tendency to depressive symptoms, anxiety, somatisation, inattention, hyperactivity, oppositional/defiant problems, and other maladaptive behaviours compared with controls. Among NT1 patients, females showed a higher propensity to anxiety, and non-treated patients displayed higher depressive symptoms. Psychological symptoms increased with age, BMI, and daytime sleepiness in patients with NT1, while a younger age was associated with more frequent somatisation symptoms. Lower cerebrospinal Hcrt-1 levels correlated with poorer social competencies, daily activities, and inattention. Diagnostic delay was associated with a higher impact of depressive symptoms and behavioural problems. NT1 in children and adolescents is associated with poorer functioning in multiple psychological domains calling for a multidisciplinary approach and monitoring to reduce disease burden and to prevent psychiatric consequences.

Evaluating routine blood and cerebrospinal fluid samples in narcolepsy patients

Cerebrospinal fluid hypocretin-1 is proven to be a precise diagnostic marker of narcolepsy Type 1 (NT1). However other characteristics of cerebrospinal fluid and blood parameters have not yet been described. The objective of this study was to evaluate the differences in routine blood and cerebrospinal fluid analyses between NT1 patients and patients suspected of hypersomnia. We collected retrospectively all measures of cerebrospinal fluid hypocretin-1 between 2019 and 2022. This yielded 612 patients out of which 146 were diagnosed with NT1 and the rest (466 patients) were used as a control group. We selected the most relevant routine samples from both blood, plasma and cerebrospinal fluid and compared the two groups. The only significantly different analytes were plasma lactate dehydrogenase and cerebrospinal fluid hypocretin-1. No other differences were found between the groups including thyroid markers, markers of neuroendocrine function, inflammatory markers in blood or cerebrospinal fluid, markers of permeability of the blood brain barrier or metabolic markers in blood samples. We found no significant differences in routine blood or cerebrospinal fluid components, neuroendocrine function, neuroinflammation and metabolic markers. The results reflect that the hypocretin system does not seem to play a chronic major role in regulation of these markers. None of the parameters routinely measured in blood in these patients could differentiate between NT1 and non-NT1 disorders besides CSF-hcrt-1.

Narcolepsy: an interface among neurology, immunology, sleep, and genetics

Narcolepsy is a primary disorder of the central nervous system resulting from genetic, environmental, and immunological interactions defined as excessive daytime sleepiness plus cataplexy, hallucinations, sleep paralysis, and sleep fragmentation. The pathophysiology is not entirely known, but the interaction among genetic predisposition, environmental exposition, and immune component with consequent hypocretin-1 deficiency is the model to explain narcolepsy type I. The mechanism of narcolepsy type II is less understood. There is a delay of over ten years for the diagnosis of narcolepsy around the world. Patients with narcolepsy have many comorbidities with a negative impact on quality of life. The treatment of narcolepsy must contain an educational approach for the family, coworkers, and patients. Scheduled naps and sleep hygiene are essential to minimize the dose of medications. Much progress has been seen in the pharmacological treatment of narcolepsy with new stimulants, different presentations of oxybate, and recent studies with orexin agonists. Narcolepsy is a rare disease that needs to be more understood and highlighted to avoid delayed diagnosis and severe disabilities in patients.

Hits and misses with animal models of narcolepsy and the implications for drug discovery

INTRODUCTION

Narcolepsy is a chronic and rare neurological disorder characterized by disordered sleep. Based on animal models and further research in humans, the dysfunctional orexin system was identified as a contributing factor to the pathophysiology of narcolepsy. Animal models played a larger role in the discovery of some of the pharmacological agents with established benefit/risk profiles.

AREAS COVERED

In this review, the authors examine the phenotypes observed in animal models of narcolepsy and the characteristics of clinically used pharmacological agents in these animal models. Additionally, the authors compare the effects of clinically used pharmacological agents on the phenotypes in animal models with those observed in narcolepsy patients.

EXPERT OPINION

Research in canine and mouse models have linked narcolepsy to the O×R2mutation and orexin deficiency, leading to new diagnostic criteria and a drug development focus. Advancements in pharmacological therapies have significantly improved narcolepsy management, with insights from both clinical experience and from animal models having led to new treatments such as low sodium oxybate and solriamfetol. However, challenges persist in addressing symptoms beyond excessive daytime sleepiness and cataplexy, highlighting the need for further research, including the development of diurnal animal models to enhance understanding and treatment options for narcolepsy.

Cataplexy Mistaken for Seizures in a Patient With Undiagnosed Narcolepsy Type I

Narcolepsy Type 1 is a sleep disorder, with cataplexy as its cardinal feature, characterized by sudden decrease or loss of muscle tone triggered by strong emotions. Cataplexy can be misdiagnosed as epileptic seizures given its clinical similarity to atonic seizures. The low prevalence of the disease added another layer of complexity in providing timely and accurate diagnosis. We report a case of a young man with recurrent episodes of falling and an inability to respond, initially misinterpreted as epileptic seizures due to findings in routine electroencephalography (EEG). Anti-seizure medications were ineffective, and subsequent ambulatory EEG revealed no epileptic activity during events. A detailed history uncovered symptoms of cataplexy and daytime sleepiness, leading to the correct diagnosis of narcolepsy type I confirmed by polysomnogram (PSG) and mean sleep latency test (MSLT). Discontinuation of anti-seizure medications and treatment with venlafaxine successfully resolved cataplexy. The case highlights the importance of a thorough clinical history in distinguishing cataplexy from seizures, as well as the caution against relying solely on EEG findings for epilepsy diagnosis. Ambulatory EEG can help exclude epileptic events, and PSG with MSLT are necessary to confirm narcolepsy type I.

Exploring exercise, physical wellbeing and the role of physiotherapy: perspectives from people with narcolepsy

Narcolepsy is associated with reduced quality of life and physical performance. The study aimed to explore the attitudes of people with Type 1 narcolepsy towards exercise and physical activity, their physical wellbeing, and the potential role of physiotherapy. Semi-structured interviews were conducted with 22 people with narcolepsy attending a dedicated outpatient narcolepsy clinic located in Dublin, Ireland. Transcripts were iteratively coded; a thematic analysis was undertaken, and key themes were identified. Four themes were identified: 'Barriers and Facilitators to Exercising', 'Social Concerns', 'Health Concerns' and 'Suggestions for the Role of Physiotherapy'. Future research should explore the potential role of exercise to help manage narcolepsy-related symptoms in this population.

Tetrad of Narcolepsy Type 1: Treatment and Management

Narcolepsy is a chronic condition that brings about excessive daytime sleepiness. It can be classified into two types: narcolepsy type 1 (presence of cataplexy, which is marked by weakness of muscles) and narcolepsy type 2 (without cataplexy). It is generally underdiagnosed, which results in delayed diagnosis of the condition. It has more prevalence in the United States of America as compared to India. The narcoleptic tetrad consists of excessive daytime sleepiness (EDS), cataplexy, sleep paralysis, and hypnagogic hallucinations. Rapid eye movement (REM) sleep behavior disorder is another characteristic feature. Research about narcolepsy has been carried out for about 145-150 years, but it is only in the last 18-20 years that there has been advancement in the underlying pathophysiology, diagnosis, and, thus, availability of better treatment. Both pharmacological and non-pharmacological methods are preferred in treating narcolepsy, yet there is no cure for it. Since the knowledge regarding this condition is very limited, it is often misunderstood, and dealing with it is mentally and socially draining, often causing anxiety in the patients, feeling of social isolation, and other significant impacts on the quality of living. Raising awareness about narcolepsy is vital to prevent further medical attention delays.

Creation of a shortened version of the Sleep Disorders Questionnaire (SDQ)

The 176-item Sleep Disorders Questionnaire (SDQ) was initially developed using canonical discriminant function analysis on 4 groups of sleep disorder patients, but it was never studied by factor analysis in its entirety. Several authors have criticized 2 of its subscales as being confounded with each other, and its narcolepsy scale as substantially over-diagnosing narcolepsy. This study describes its first exploratory factor analysis (EFA), the intent of which was to reassess item membership on the 4 existing subscales and to derive new scales to improve differential diagnosis between patient groups. It was also hoped that EFA could reduce the total number of questions, to increase speed of completion. The EFA was performed on the anonymized SDQ results from a retrospective review of the charts of 2131 persons from 7 sleep disorders clinics and research centers. Factors were assessed via scree plots and eigenvalues. The EFA identified four main factors: insomnia, daytime sleepiness, substance use, and sleep-disordered breathing. The insomnia factor had 3 subfactors: psychological symptoms of insomnia, subjective description of insomnia, and insomnia due to periodic limb movements. The sleepiness factor had two subfactors: daytime sleepiness and neurological symptoms of narcolepsy. The novel substance use factor was homogeneous, as was the sleep-disordered breathing factor. Importantly, the EFA reassigned items from the original SDQ's NAR, PSY, and PLM subscales to five of the new subscales. The Sleep Apnea (SA) subscale emerged mostly unchanged. The 7 resulting factors comprised only 66 items of the original 176-item SDQ. These results have allowed the creation of a new shorter questionnaire, to be called the SDQ-2. External validation of the SDQ-2 is currently underway. It will likely prove to be a superior differential diagnostic instrument for sleep disorders clinics, compared to the original SDQ.

Characterization of the Increase in Narcolepsy following the 2009 H1N1 Pandemic in Sweden

(1) Background: In the context of the H1N1 pandemic and the Pandemrix vaccination campaign, an increased number of narcolepsy cases were noted in several countries. In Sweden, this phenomenon was attributed to the effect of the Pandemrix vaccination in the first place. Studies from China indicated that narcolepsy could occur as a consequence of the H1N1 infection itself. We performed an analysis of the increase, with a specific interest in age and sex distribution. We also aimed to validate the origin of the excess cases, post hoc. (2) Methods: Data for narcolepsy patients (ICD code G 47.4, both type 1 and type 2) distributed by sex and age at 5-year intervals, annually between 2005 and 2017, were retrieved from the National Patient Register. Information on the total population was collected from the Swedish Population Register. (3) Results: The number of narcolepsy cases increased markedly from 2009 to 2014 compared to the period before 2009. A particular increase in 2011 among children and teenagers was observed. The sex ratio did not change significantly during the study period. (4) Conclusions: Our results support an association between the increased prevalence of narcolepsy cases and Pandemrix vaccination, but the effect of the virus itself cannot be ruled out as a contributing factor.

Connecting the dots: An updated review of the role of autoimmunity in narcolepsy and emerging immunotherapeutic approaches

BACKGROUND

Narcolepsy type 1 (NT1) is a chronic disorder characterized by pathological daytime sleepiness and cataplexy due to the disappearance of orexin immunoreactive neurons in the hypothalamus. Genetic and environmental factors point towards a potential role for inflammation and autoimmunity in the pathogenesis of the disease. This study aims to comprehensively review the latest evidence on the autoinflammatory mechanisms and immunomodulatory treatments aimed at suspected autoimmune pathways in NT1.

METHODS

Recent relevant literature in the field of narcolepsy, its autoimmune hypothesis, and purposed immunomodulatory treatments were reviewed.

RESULTS

Narcolepsy is strongly linked to specific HLA alleles and T-cell receptor polymorphisms. Furthermore, animal studies and autopsies have found infiltration of T cells in the hypothalamus, supporting T cell-mediated immunity. However, the role of autoantibodies has yet to be definitively established. Increased risk of NT1 after H1N1 infection and vaccination supports the autoimmune hypothesis, and the potential role of coronavirus disease 2019 and vaccination in triggering autoimmune neurodegeneration is a recent finding. Alterations in cytokine levels, gut microbiota, and microglial activation indicate a potential role for inflammation in the disease's development. Reports of using immunotherapies in NT1 patients are limited and inconsistent. Early treatment with IVIg, corticosteroids, plasmapheresis, and monoclonal antibodies has seldomly shown some potential benefits in some studies.

CONCLUSION

The current body of literature supports that narcolepsy is an autoimmune disorder most likely caused by T-cell involvement. However, the potential for immunomodulatory treatments to reverse the autoinflammatory process remains understudied. Further clinical controlled trials may provide valuable insights into this area.

ADHD in narcolepsy: A closer look at prevalence and ties

The reported prevalence of attention deficit hyperactivity disorder (ADHD) in narcolepsy varies considerably, while the associated factors remain inadequately established. A systematic search of studies published in PubMed, EMBASE, and the Cochrane Library was performed from inception to March 2023. Ten studies with 839 patients with narcolepsy were included in the study. Utilizing a random effects model, the pooled prevalence of ADHD in narcolepsy was 25% (95% CI, 14-38%). Notably, patients with narcolepsy type 2 showed a significantly higher prevalence of ADHD than that of narcolepsy type 1 (46% vs. 20%, p = 0.045). Furthermore, the rate of ADHD was notably elevated in narcolepsy compared with the healthy controls (odds ratio 9.59, 95% CI, 4.06-22.63, p < 0.001). Several factors such as excessive daytime sleepiness (EDS), fatigue, insomnia severity, and the quality of life were significantly associated with ADHD in narcolepsy (all ps < 0.05). These findings highlight the importance of monitoring and managing ADHD in narcolepsy, and provide a clue to help reducing ADHD by intervening in these associated factors.

Narcolepsy and psychiatric disorders: A bidirectional Mendelian randomization study

Since the introduction of the concept of narcolepsy, there has been a proliferation of discussions about its association with psychiatry. To elucidate the causal role of narcolepsy in the three psychiatric disorders [i.e., schizophrenia (SCZ), major depressive disorder (MDD), and attention-deficit hyperactivity disorder (ADHD)], we applied a bidirectional Mendelian randomization study using two stages (discovery stage and validation stage) and data from three different genome-wide association studies of narcolepsy. The estimates from different stages were combined using fixed-effects meta-analysis. Our findings suggest that narcolepsy is associated with an increased risk of SCZ. Conversely, MDD may be causally related to narcolepsy. A causal relationship between narcolepsy and ADHD was excluded.

Exploring the Literature on Narcolepsy: Insights into the Sleep Disorder That Strikes during the Day

Narcolepsy is a chronic sleep disorder that disrupts the regulation of a person's sleep-wake cycle, leading to significant challenges in daily functioning. It is characterized by excessive daytime sleepiness, sudden muscle weakness (cataplexy), sleep paralysis, and vivid hypnagogic hallucinations. A literature search was conducted in different databases to identify relevant studies on various aspects of narcolepsy. The main search terms included "narcolepsy", "excessive daytime sleepiness", "cataplexy", and related terms. The search was limited to studies published until May 2023. This literature review aims to provide an overview of narcolepsy, encompassing its causes, diagnosis, treatment options, impact on individuals' lives, prevalence, and recommendations for future research. The review reveals several important findings regarding narcolepsy: 1. the classification of narcolepsy-type 1 narcolepsy, previously known as narcolepsy with cataplexy, and type 2 narcolepsy, also referred to as narcolepsy without cataplexy; 2. the genetic component of narcolepsy and the complex nature of the disorder, which is characterized by excessive daytime sleepiness, disrupted sleep patterns, and potential impacts on daily life activities and social functioning; and 3. the important implications for clinical practice in the management of narcolepsy. Healthcare professionals should be aware of the different types of narcolepsies and their associated symptoms, as this can aid in accurate diagnosis and treatment planning. The review underscores the need for a multidisciplinary approach to narcolepsy management, involving specialists in sleep medicine, neurology, psychiatry, and psychology. Clinicians should consider the impact of narcolepsy on a person's daily life, including their ability to work, study, and participate in social activities, and provide appropriate support and interventions. There are several gaps in knowledge regarding narcolepsy. Future research should focus on further elucidating the genetic causes and epigenetic mechanisms of narcolepsy and exploring potential biomarkers for early detection and diagnosis. Long-term studies assessing the effectiveness of different treatment approaches, including pharmacological interventions and behavioral therapies, are needed. Additionally, there is a need for research on strategies to improve the overall well-being and quality of life of individuals living with narcolepsy, including the development of tailored support programs and interventions.

Retrospective cohort study of hypersomnias of central origin from two Australian tertiary sleep disorders services

BACKGROUND

Hypersomnias of central origin (HOCO) are diverse in origin and symptomatology and remain poorly described in an Australian population. We hypothesised that the rate of human leukocyte antigen (HLA) DQB1*0602 positivity in the Australian cohort would be comparable to international registries.

AIMS

The current study aims to evaluate epidemiological and clinical characteristics of Australian patients with HOCO, including prevalence of HLA DQB1*0602 positivity, the most specific HLA marker associated with narcolepsy.

METHODS

This is a retrospective study. Patients ≥ 16 years of age presenting with symptoms of hypersomnolence who attended one of two Australian sleep centres (New South Wales and Queensland) in the preceding 24 months and had undergone both HLA serology and multiple sleep latency tests (MSLTs) were included. Main outcome measures included demographics, HLA DQB1*0602 positivity, MSLT, and clinical parameters (presence of auxiliary narcolepsy symptoms, laboratory tests, relevant prescribed medications).

RESULTS

Eighty-eight patients were included. HLA DQB1*0602 positivity was highest in those with type 1 narcolepsy (NT1) (95.7%) and lowest in those without a classifiable disorder (9.1%). Mean sleep latency was lowest and number of sleep-onset rapid eye movement periods (SOREMPs) highest in the NT1 group. Comorbid disorders, particularly depression and overweight/obesity, were prevalent in all cohorts. Across all diagnostic groups, dexamphetamine was the most commonly prescribed agent for excessive daytime sleepiness.

CONCLUSIONS

Patients with HOCO assessed in two specialised Australian clinics demonstrate comparable clinical characteristics to other published cohorts internationally; however, available pharmacological agents in Australia do not reflect international standards of care.

Reliability and validity of the Japanese version of the Ullanlinna Narcolepsy Scale and Swiss Narcolepsy Scale for screening Japanese individuals with narcolepsy type 1

OBJECTIVE

To validate the Japanese versions of the Ullanlinna Narcolepsy Scale (J-UNS) and Swiss Narcolepsy Scale (J-SNS) for screening narcolepsy in the Japanese population and to discuss strategies for their use in hypersomniac individuals.

METHODS

We selected 451 outpatients with excessive daytime sleepiness (EDS) already diagnosed according to the International Classification of Sleep Disorders third edition. They responded to both scales twice at 1-month intervals. After eliminating individuals who met the exclusion criteria, validity and reliability analyses were performed on 408 and 381 participants, respectively.

RESULTS

Patients with narcolepsy type 1 (NT1) displayed higher J-UNS and lower J-SNS scores than those with NT2 and other sleep disorders. The intraclass correlation coefficients and weighted κ coefficient for scale scores in the total participants and patients with NT1 were ≥0.70 and ≥ 0.40, respectively, indicating high reliability. Furthermore, both the sensitivity and specificity of these scales upon using the original cut-off scores (14 for UNS and 0 for SNS) for detecting NT1 were 0.70 or ≥0.70, suggesting high validity. Additionally, the receiver operating characteristic curve analysis revealed that the best cut-off score did not change for the J-SNS but that for the J-UNS, it increased to 18. In our study, the scale's sensitivity and specificity changed from 96% to 82% and 58%-78%, respectively.

CONCLUSIONS

Both scales revealed satisfactory screening abilities for NT1 in the Japanese population. However, it may be better to use J-UNS cut-off scores of 18 for a population with EDS.

Circadian rhythm of daytime sleepiness in pediatric narcolepsy: A pilot study

BACKGROUND AND OBJECTIVE

Excessive daytime sleepiness (EDS) has been far back reported as the most disabling symptom in the pediatric narcoleptic patients. However, there is a lack of studies to examine the circadian rhythms of EDS in pediatric narcoleptic population. Therefore, we aim to investigate the circadian rhythm of EDS in pediatric narcolepsy patients.

METHODS

We identified 50 pediatric narcoleptic patients (36 males and 14 females, mean age 13.68 ± 2.75 years). Data were collected through interviews and the relevant questionnaires (children depression inventory [CDI] and the pediatric quality of life inventory [PedsQL]).

RESULT

The frequencies of sleep attacks during different intervals of the day differed significantly, with higher frequency in the morning (p < .001). The times of sleep attacks in the morning and in the afternoon were significantly associated with the degree of impairment on class and the severity of worry about sleepiness, with spearman correlation coefficient ranging from .289 to .496 (p < .05). The total scores of PedsQL and CDI differed significantly among morning sleepiness dominant, afternoon sleepiness dominant, and evening sleepiness dominant groups (p = .042, p = .040). The severity scores of the narcoleptic patients' sleepiness had two peaks, one of which occurred at 16:00, and the other peaks occurred at about 11:00.

CONCLUSION

These results suggest that changes based on the circadian rhythm of sleepiness of the pediatric narcoleptic patients should be made in the treatment strategy. In addition, regulating the secretion of melatonin could serve as a promising treatment to relieve sleepiness in the future.

Autoimmune/inflammatory syndrome induced by adjuvants (ASIA): past, present, and future implications

Adjuvants, as the name indicates, are adjoined material aimed to assist in functioning as when added to vaccines they are meant to boost the effect and strongly stimulate the immune system. The response of the immune system can be unpredictable, and the autoimmune/inflammatory syndrome induced by adjuvants (ASIA) was developed to address possible adverse reactions of an autoimmune and inflammatory type that may be caused by adjuvants. While ASIA, as a syndrome, was coined and defined in 2011; reports describing patients with vague and nonspecific clinical symptoms following vaccinations appeared much earlier. In other words, ASIA came to define, arrange, and unite the variety of symptoms, related to autoimmunity, caused not by the vaccine itself, rather by the adjuvant part of the vaccine such as aluminum, among others. Accordingly, the introduction of ASIA enabled better understanding, proper diagnosis, and early treatment of the disorder. Furthermore, ASIA was shown to be associated with almost all body systems and various rheumatic and autoimmune diseases such as systemic lupus erythematosus, antiphospholipid syndrome, and systemic sclerosis. In addition, the correlation between COVID-19 and ASIA was noticed during the pandemic. In this review, we summarized the reported effects of adjuvants and medical literature before and after ASIA was defined, the several ways ASIA can manifest and impact different systems of the body, and the incidences of ASIA during the COVID-19 pandemic. It is important to clarify, that vaccines are among, if not the, most effective means of fighting infectious diseases however, we believe that vaccines manufacturing is not above criticism, particularly when it comes to added substances possessing a risk of side effects.

International Consensus Statement on Obstructive Sleep Apnea

BACKGROUND

Evaluation and interpretation of the literature on obstructive sleep apnea (OSA) allows for consolidation and determination of the key factors important for clinical management of the adult OSA patient. Toward this goal, an international collaborative of multidisciplinary experts in sleep apnea evaluation and treatment have produced the International Consensus statement on Obstructive Sleep Apnea (ICS:OSA).

METHODS

Using previously defined methodology, focal topics in OSA were assigned as literature review (LR), evidence-based review (EBR), or evidence-based review with recommendations (EBR-R) formats. Each topic incorporated the available and relevant evidence which was summarized and graded on study quality. Each topic and section underwent iterative review and the ICS:OSA was created and reviewed by all authors for consensus.

RESULTS

The ICS:OSA addresses OSA syndrome definitions, pathophysiology, epidemiology, risk factors for disease, screening methods, diagnostic testing types, multiple treatment modalities, and effects of OSA treatment on multiple OSA-associated comorbidities. Specific focus on outcomes with positive airway pressure (PAP) and surgical treatments were evaluated.

CONCLUSION

This review of the literature consolidates the available knowledge and identifies the limitations of the current evidence on OSA. This effort aims to create a resource for OSA evidence-based practice and identify future research needs. Knowledge gaps and research opportunities include improving the metrics of OSA disease, determining the optimal OSA screening paradigms, developing strategies for PAP adherence and longitudinal care, enhancing selection of PAP alternatives and surgery, understanding health risk outcomes, and translating evidence into individualized approaches to therapy.

Pharmacological options for narcolepsy: are they the way forward?

INTRODUCTION

Narcolepsy is an under-recognized, rare neurologic disorder of hypersomnolence that is associated with increased mortality and medical and psychiatric co-morbidities. Narcolepsy exerts a substantial economic burden on patients and society. There is currently no cure, and life-long symptomatic therapy is needed. Available drugs do not modify the disease course.

AREAS COVERED

This manuscript provides an overview of narcolepsy symptoms, diagnosis, pathophysiology, current pharmacotherapies, and emerging treatments. Gaps and unresolved issues in diagnosis and management of narcolepsy are discussed to answer whether pharmacological options are the way forward.

EXPERT OPINION

Diagnostic criteria for narcolepsy (ICSD-3) need revision and greater clarity. Improved recognition of cataplexy and other symptoms through educational outreach, new biomarkers, improved test scoring through artificial intelligence algorithms, and use of machine learning may facilitate earlier diagnosis and treatment. Pharmacological options need improved symptomatic therapy in addition to targeted therapies that address the loss of hypocretin signaling. Optimal narcolepsy care also needs a better understanding of the pathophysiology, recognition of the different phenotypes in narcolepsy, identification of at-risk individuals and early recognition of symptoms, better diagnostic tools, and a database for research and disease monitoring of treatment, side-effects, and comorbidities.

Characteristics and outcomes of cases with methylphenidate abuse, dependence or withdrawal: an analysis of spontaneous reports in EudraVigilance

Methylphenidate (MPH) is a central nervous stimulant, which is mainly used in attention deficit hyperactivity disorder (ADHD) and narcolepsy. In recent years, rising MPH prescription volumes have drawn attention to possible misuse. We analyzed data on suspected MPH abuse, dependence or withdrawal reported to the EudraVigilance database (1996-2019), comparing case characteristics (e.g. age, indications and outcome). In 1531 cases from 35 countries (median: 29 years, 57.6% male), 42.3% had been diagnosed with ADHD and 8.0% with narcolepsy. Narcolepsy cases were older than ADHD cases (mean age: 47 vs. 22 years), and used co-medications more frequently (79.4 vs. 47.8%). Intravenous MPH administration was most common among individuals not diagnosed with ADHD or narcolepsy. A history of abuse, dependence or withdrawal of any substance was more often documented in fatal than in nonfatal cases (49.0 vs. 22.5%), whereas differences regarding the route of administration were less pronounced. Minors, who presumably received MPH for ADHD treatment, presented less frequently with serious outcomes than older cases or those without an approved indication. Prescribers should exercise caution in adult MPH users and should make a thorough co-medication assessment. Finally, more research on substance abuse in narcolepsy patients is required, which should include comorbidities and co-medication.

Calcium, magnesium, potassium, and sodium oxybates oral solution for cataplexy or excessive daytime sleepiness associated with narcolepsy

INTRODUCTION

Lower-sodium oxybate (LXB) is a novel formulation that is approved by the US Food and Drug Administration (FDA) to treat cataplexy and excessive daytime sleepiness (EDS) in adult patients and children ≥ 7 years with narcolepsy. LXB contains 92 percent less sodium than sodium oxybate (SXB), which adds 550-1640 mg of sodium/day at usual doses of 3-9 grams per day. The FDA has declared LXB to be clinically superior to SXB due to greater safety by reducing the chronic sodium load. Narcolepsy patients have high comorbidities for hypertension and cardiovascular disease, conditions which can be adversely affected by high sodium intake.

AREAS COVERED

This drug review discusses narcolepsy, current and upcoming pharmacotherapy, and LXB chemistry, pharmacodynamics, pharmacokinetics, and metabolism. Published results from LXB's phase 1 studies, a phase 3 study, and 2 post-marketing studies are reviewed. Databases searched included Pubmed, Google Scholar, Lexi-Comp, Scopus, Science, and Ovid.

EXPERT OPINION

LXB is efficacious in treating daytime sleepiness and cataplexy in adults and children ≥ 7 years with narcolepsy. Using LXB instead of SXB formulations may benefit narcolepsy patients with cardiovascular comorbidities and hypertension, but long-term studies are needed to prove it.

Differences in psychosocial factors and sleep study findings between delayed sleep-wake phase disorder and hypersomnia in teenagers

Central hypersomnia (HS) and delayed sleep-wake phase disorder (DSWPD) appear commonly in adolescents, and they severely reduce quality of life and have an enormous impact on academic performance and other aspects of development. Although these disorders are thought to be considerably different in etiology, it is sometimes difficult to distinguish them because of their similar clinical features. This study aimed to compare psychosocial factors and sleep study findings between HS and DSWPD in teenagers. The clinical data of 89 teenagers who visited the psychiatric section of the Sleep Medicine Center of Nihon University Itabashi Hospital from January 2013 to December 2019 were analyzed. Psychosocial factors were evaluated at the first visit, and polysomnography (PSG) and the multiple sleep latency test (MSLT) were performed for patients deemed to require definitive diagnosis. Compared with patients with HS, those with DSWPD had a higher rate of mother's employment, introversion, adjustment problems, events that triggered the disorder, concurrent mental disorders, habitual lateness, and difficulty attending school or work. PSG did not show any differences in sleep parameters between the two disorders, except for sleep latency. On the MSLT, sleep latency was shorter in those with HS on the second, third, and fourth tests. The present results suggest that focusing on psychosocial factors could be useful for differential diagnosis of the two disorders that appear commonly in adolescents.

Narcolepsy and emotions: Is there a place for a theory of mind approach?

Narcolepsy type 1 is a central disorder of hypersomnolence characterized by excessive daytime sleepiness, rapid eye movement sleep-related manifestations, and cataplexy. In the current literature there is general agreement regarding neural correlates of Narcolepsy type 1 that appear to be related to anatomical and functional abnormalities in the hypothalamic region. In the last two decades, researchers shed light on the neurological bases of cataplexy by focusing on the neurobiological correlates of emotions. Although the results of these studies differ, they all point to an impairment in the amygdala and hypothalamus functions that are known to be involved in emotional processing, suggesting an impairment in this domain in narcoleptic patients. Indeed, despite heterogeneous results, several studies showed that narcoleptic patients differed from healthy controls in processing emotional stimuli. From a behavioral point of view, these findings suggest that alterations in emotional processing may be driven, at least in part, by compensatory strategies to avoid or reduce the frequency of cataplexy attacks. Surprisingly, the only study exploring in NT1 the behavioural performances in emotional facial recognition found no differences between NT1 adults and controls. We hypothesize that narcoleptic patients may present an alteration in a more complex socio-cognitive ability that is related to emotional processing, namely Theory of Mind. This review aims to investigate the literature supporting this hypothesis and to propose possible future developments on this topic.

Evidence of Accidental Dosing Errors with Immediate-Release Sodium Oxybate: Data from the US Food and Drug Administration Adverse Event Reporting System

INTRODUCTION

Sodium oxybate has been approved by the US Food and Drug Administration (FDA) to treat narcolepsy for 20 years; however, the only available products have been immediate-release (IR) formulations given twice nightly-once at bedtime and a second dose 2.5-4 h later-creating inherent risks with dosing administration errors.

OBJECTIVES

Evidence and risks associated with accidental ingestion of the second IR oxybate dose < 2.5 h after the first dose were examined.

METHODS

The FDA Adverse Event Reporting System database was searched for "inappropriate schedule of product administration" with IR sodium oxybate or calcium/magnesium/potassium/sodium oxybates; reports classified as serious and with IR oxybate as the suspect product were further analyzed.

RESULTS

Of 541 reports meeting the search criteria, 178 were classified as serious: accidental early administration of the second dose resulting in adverse events (AEs; n = 41); "near miss" (no harm reported following early dosing; n = 9); intentionally taking second dose early (n = 25); other inappropriate use (late dosing/not taking daily; n = 102); and one duplicate report. Of the 41 reports of taking the second dose too early resulting in AEs, 22% (9/41) used emergency services and 27% (11/41) resulted in hospitalizations. AEs reported with accidentally taking the second dose too early included CNS depression, bradycardia, respiratory depression, dizziness, seizure, confusion, delirium, difficulty awakening, drowsiness, falls, nausea, vomiting, and enuresis.

CONCLUSIONS

Patients, caregivers, clinicians, and Poison Control Centers should be aware of the risk of accidentally dosing twice-nightly IR oxybates earlier than 2.5 h after the first dose and the subsequent harm that may occur with early dosing.

Can COVID-19 Vaccines Induce Premature Non-Communicable Diseases: Where Are We Heading to?

According to the WHO, as of January 2023, more than 850 million cases and over 6.6 million deaths from COVID-19 have been reported worldwide. Currently, the death rate has been reduced due to the decreased pathogenicity of new SARS-CoV-2 variants, but the major factor in the reduced death rates is the administration of more than 12.8 billion vaccine doses globally. While the COVID-19 vaccines are saving lives, serious side effects have been reported after vaccinations for several premature non-communicable diseases (NCDs). However, the reported adverse events are low in number. The scientific community must investigate the entire spectrum of COVID-19-vaccine-induced complications so that necessary safety measures can be taken, and current vaccines can be re-engineered to avoid or minimize their side effects. We describe in depth severe adverse events for premature metabolic, mental, and neurological disorders; cardiovascular, renal, and autoimmune diseases, and reproductive health issues detected after COVID-19 vaccinations and whether these are causal or incidental. In any case, it has become clear that the benefits of vaccinations outweigh the risks by a large margin. However, pre-existing conditions in vaccinated individuals need to be taken into account in the prevention and treatment of adverse events.

National Estimates of Narcolepsy in Korea

BACKGROUND AND PURPOSE

Epidemiological data on narcolepsy are rare in South Korea. We aimed to provide an overview of the burden of narcolepsy and its temporal trend in South Korea.

METHODS

Patients with narcolepsy were identified by their registration in the Rare and Intractable Disease (RID) register and the Health Insurance Review and Assessment database. Individuals registered in the RID program with the code V234 were considered as having 'definite narcolepsy', while those who claimed health insurance with G47.4 as the primary diagnostic code were considered as having 'probable narcolepsy'. We estimated the annual prevalence, incidence, and medical costs of narcolepsy between 2010 and 2019.

RESULTS

The prevalence of definite narcolepsy was 8.4/100,000 in 2019, peaking at 32.0/100,000 in those aged 15-19 years. The prevalence was higher in males, with a relative risk of 1.72. The prevalence has increased over the past 6 years, with an average annual growth rate (AAGR) of 12.2%. The prevalence of probable narcolepsy was 10.7/100,000 in 2019. The incidence of definite narcolepsy increased up to 1.3/100,000 in 2019 with an AAGR of 7.1%. Annual medical expenditure for definite narcolepsy gradually increased up to 4.1 billion KRW in 2019, with a compound annual growth rate of 11.9%.

CONCLUSIONS

This study has provided the first nationwide estimates for narcolepsy in South Korea. The prevalence of diagnosed narcolepsy in South Korea was at the low end of the range of narcolepsy prevalence rates reported for other countries. However, the prevalence and incidence have been steadily increasing over the past decade.

Randomized, crossover, open-label study of the relative bioavailability and safety of FT218, a once-nightly sodium oxybate formulation: Phase 1 study in healthy volunteers

OBJECTIVES

Treatment for narcolepsy with sodium oxybate (SXB) has required twice-nightly dosing, at bedtime and 2.5-4 h later. This study evaluated the pharmacokinetics of FT218, an investigational, extended-release, once-nightly formulation of SXB (ON-SXB), vs twice-nightly SXB.

METHODS

In this phase 1, open-label study, healthy volunteers were randomized (1:1) to ON-SXB 6 g or twice-nightly SXB (two 3-g doses administered 4 h apart); minimum 3-day washout before crossover. Doses were administered 2 h post-evening meal. Blood samples for pharmacokinetic assessments were collected predose and up to 14 h after the first dose during each treatment period.

RESULTS

Twenty-eight participants were enrolled (mean age, 39.6 years; 54% women; 93% white). Mean ± SEM area under the concentration-time curve for ON-SXB was 282.7 ± 30.2  μg·h/mL vs 273.3 ± 27.8 μg·h/mL for twice-nightly SXB. Geometric mean ratio (GMR; 90% CI) was 102.9 (98.0-108.0). Maximum γ-hydroxybutyrate (GHB) plasma concentration (C_max) was 65.8 ± 4.0 μg/mL for ON-SXB vs 77.1 ± 4.9 μg/mL for twice-nightly SXB (GMR [90% CI], 88.3 [80.5-97.0]). The GMR (90% CI) for GHB plasma concentrations 8 h post dose (C_8h) for ON-SXB vs twice-nightly SXB was 61.7 (45.8-83.0). The most frequently reported adverse events were the same for ON-SXB and twice-nightly SXB (nausea, dizziness, somnolence, vomiting).

CONCLUSIONS

GHB exposure and C_max with one 6-g dose of ON-SXB were bioequivalent to those with two 3-g doses of twice-nightly SXB, whereas C_8h was lower with ON-SXB. If approved, ON-SXB will provide a single bedtime oxybate option, with clinically relevant pharmacologic exposure during the entire sleep period.

Body Weight and Metabolic Rate Changes in Narcolepsy: Current Knowledge and Future Directions

Narcolepsy is a known auto-immune disease that presents mainly in the teenage years with irresistible sleep attacks. Patients with narcolepsy, especially NT1, have been found to have a high prevalence of obesity and other metabolic derangements. This narrative review aimed to address the relationship between narcolepsy and changes in weight and metabolic rate, and discuss potential mechanisms for weight gain and metabolic changes and future research agendas on this topic. This article will provide a balanced, up-to-date critical review of the current literature, and delineate areas for future research, in order to understand the pathophysiological metabolic changes in narcolepsy. Articles using predefined keywords were searched for in PubMed and Google Scholar databases, with predefined inclusion and exclusion criteria. Compared to controls, patients with narcolepsy are more likely to be obese and have higher BMIs and waist circumferences. According to recent research, weight gain in narcolepsy patients may be higher during the disease's outset. The precise mechanisms causing this weight gain remains unknown. The available information, albeit limited, does not support differences in basal or resting metabolic rates between patients with narcolepsy and controls, other than during the time of disease onset. The evidence supporting the role of orexin in weight gain in humans with narcolepsy is still controversial, in the literature. Furthermore, the available data did not show any appreciable alterations in the levels of CSF melanin-concentrating hormone, plasma and CSF leptin, or serum growth hormone, in relation to weight gain. Other mechanisms have been proposed, including a reduction in sympathetic tone, hormonal changes, changes in eating behavior and physical activity, and genetic predisposition. The association between increased body mass index and narcolepsy is well-recognized; however, the relationship between narcolepsy and other metabolic measures, such as body fat/muscle distribution and metabolic rate independent of BMI, is not well documented, and the available evidence is inconsistent. Future longitudinal studies with larger sample sizes are needed to assess BMR in patients with narcolepsy under a standard protocol at the outset of narcolepsy, with regular follow-up.

Pharmacological Interventions for Excessive Daytime Sleepiness in Adults with Narcolepsy: A Systematic Review and Network Meta-Analysis

Narcolepsy is a neurological disease characterized by a core symptom of excessive daytime sleepiness (EDS). Although effective pharmacological interventions for narcolepsy have been developed, a lack of comparative evidence supporting the relative efficacy among these medications leads to clinical treatment challenge. Therefore, we performed a network meta-analysis to overcome this lack of head-to-head comparisons. Databases were searched systematically for randomized controlled trials that compared pharmacological interventions for narcolepsy. The primary outcomes were changes in the Epworth Sleepiness Scale (ESS) and the Maintenance of Wakefulness Test (MWT). A random-effects frequentist network meta-analysis was conducted. A total of 19 RCTs involving 2504 patients were included. Solriamfetol achieved the highest ranking based on the P-scores, and was superior to pitolisant (MD −2.88, 95% CI −4.89–−0.88) and sodium oxybate (MD −2.56, 95% CI −4.62–−0.51) for ESS change. Consistently, solriamfetol achieved the highest ranking according to MWT change, and was superior to pitolisant (SMD 0.45, 95% CI 0.02–0.88) and modafinil (SMD 0.42, 95% CI 0.05–0.79). Although solriamfetol demonstrated superior efficacy in EDS improvement, evidence from the clustered ranking plot supported that efficacy–safety profiles of pitolisant, sodium oxybate, and modafinil are more balanced than solriamfetol. Therefore, the choice of medication for EDS in narcolepsy should be made on an individual basis.

Pfizer/BioNTech SARS-CoV-2 vaccine as a potential trigger for the development of narcolepsy: a case report

Narcolepsy is a rare condition in Israel. Currently, the incidence of narcolepsy following SARS-CoV-2 vaccination in Israel is unknown. We are reporting a case report of a 51-year-old woman of Ashkenazi Jewish descent who was evaluated for complaints of excessive daytime sleepiness and relative functional decline that immediately followed receipt of the Pfizer/BioNTech SARS-CoV-2 vaccination. Evaluation of patient-reported data with polysomnography and multiple sleep latency test was consistent with narcolepsy with cataplexy, meeting the criteria for a diagnosis of type 1 narcolepsy. Further investigation included human leukocyte antigen testing. Prior studies have demonstrated genetic, immunological, and environmental factors associated with narcolepsy following other vaccinations. This case is a valuable contribution to the literature as there are no prior reports of type 1 narcolepsy following SARS-CoV-2 vaccination in the State of Israel.

CITATION

Mahamid A, Bornstein RJ, Amir H. Pfizer/BioNTech SARS-CoV-2 vaccine as a potential trigger for the development of narcolepsy: a case report. J Clin Sleep Med. 2022;18(10):2503-2506.

Prevalence, incidence, and medications of narcolepsy in Japan: a descriptive observational study using a health insurance claims database

The objectives of this study were to describe prevalence, incidence, and medications among patients who were diagnosed with narcolepsy in Japan using a claims database. Patients diagnosed with narcolepsy were identified from January 2010 to December 2019 using an employment-based health insurance claims database compiled by JMDC Inc. The prevalence and incidence of narcolepsy were estimated annually in the overall population and by age and sex among employees and their dependents aged < 75 years. Medications, examined for each quarter in the overall population, were modafinil, methylphenidate, pemoline, tricyclic antidepressants, selective serotonin reuptake inhibitors, and serotonin-norepinephrine reuptake inhibitors. We identified 1539 patients with narcolepsy. The overall annual prevalence increased from 5.7 to 18.5/100,000 persons in 2010 and 2019, respectively. Large increases were found from 2010 to 2019 in patients aged 20-29 years and 10-19 years, with the highest prevalence in 2019 (9.7-37.5/100,000 persons and 5.0-27.1/100,000 persons). The overall incidence slightly increased from 3.6 to 4.3/100,000 person-year from 2010 to 2019, and the highest incidence was found in patients aged 20-29 years and 10-19 years (5.8-11.3/100,000 person-year, and 3.8-7.4/100,000 person-year from 2010 to 2019, respectively). Methylphenidate and modafinil were commonly prescribed in 2010 (27.3-38.9% and 17.5-45.5%, respectively). Methylphenidate prescriptions declined during the 10 years, whereas modafinil prescriptions increased (15.6-17.1% and 43.8-45.8% in 2019, respectively). The estimated prevalence and incidence of narcolepsy appeared to increase from 2010 to 2019, especially in teenagers and 20-year olds.

Supplementary Information

The online version contains supplementary material available at 10.1007/s41105-022-00406-4.

Increased incidence of pediatric narcolepsy following the 2009 H1N1 pandemic: a report from the pediatric working group of the sleep research network

This study was aimed to evaluate the yearly incidence of pediatric narcolepsy prior to and following the 2009 H1N1 pandemic and to evaluate seasonal patterns of narcolepsy onset and associations with H1N1 influenza infection in the United States. This was a multicenter retrospective study with prospective follow-up. Participants were recruited from members of the Pediatric Working Group of the Sleep Research Network including 22 sites across the United States. The main outcomes were monthly and yearly incident cases of childhood narcolepsy in the United States, and its relationship to historical H1N1 influenza data. A total of 950 participants were included in the analysis; 487 participants were male (51.3%). The mean age at onset of excessive daytime sleepiness (EDS) was 9.6  ±  3.9 years. Significant trend changes in pediatric narcolepsy incidence based on EDS onset (p  &lt;  .0001) occurred over the 1998–2016 period, peaking in 2010, reflecting a 1.6-fold increase in narcolepsy incidence. In addition, there was significant seasonal variation in narcolepsy incident cases, with increased cases in spring (p  &lt;  .05). Cross-correlation analysis demonstrated a significant correlation between monthly H1N1 infection and monthly narcolepsy incident cases (p  =  .397, p  &lt;  .0001) with a lag time of 8 months. We conclude that there is a significant increase in pediatric narcolepsy incidence after the 2009 H1N1 pandemic in the United States. However, the magnitude of increase is lower than reported in European countries and in China. The temporal correlation between monthly H1N1 infection and monthly narcolepsy incidence, suggests that H1N1 infection may be a contributing factor to the increased pediatric narcolepsy incidence after the 2009 H1N1 pandemics.

Sleep-Related Drug Therapy in Special Conditions: Children

Pharmacologic treatment of the most common pediatric sleep disorders lacks evidence, and alternative methods, which have been proved to alleviate the symptoms, are preferred in most cases. The implementation of specific guidelines is of great importance because sleep disorders in children are not rare and they can negatively affect children's development and their cognitive and social skills. This article summarizes the current therapeutic management of sleep disorders in children, bearing in mind the absence of evidence-based guidelines on this topic.

Clinical characteristics of a large cohort of patients with narcolepsy candidate for pitolisant: a cross-sectional study from the Italian PASS Wakix® Cohort

Introduction

Narcolepsy is a chronic and rare hypersomnia of central origin characterized by excessive daytime sleepiness and a complex array of symptoms as well as by several medical comorbidities. With growing pharmacological options, polytherapy may increase the possibility of a patient-centered management of narcolepsy symptoms. The aims of our study are to describe a large cohort of Italian patients with narcolepsy who were candidates for pitolisant treatment and to compare patients’ subgroups based on current drug prescription (drug-naïve patients in whom pitolisant was the first-choice treatment, switching to pitolisant from other monotherapy treatments, and adding on in polytherapy).

Methods

We conducted a cross-sectional survey based on Italian data from the inclusion visits of the Post Authorization Safety Study of pitolisant, a 5-year observational, multicenter, international study.

Results

One hundred ninety-one patients were enrolled (76.4% with narcolepsy type 1 and 23.6% with narcolepsy type 2). Most patients (63.4%) presented at least one comorbidity, mainly cardiovascular and psychiatric. Pitolisant was prescribed as an add-on treatment in 120/191 patients (62.8%), as switch from other therapies in 42/191 (22.0%), and as a first-line treatment in 29/191 (15.2%). Drug-naive patients presented more severe sleepiness, lower functional status, and a higher incidence of depressive symptoms.

Conclusion

Our study presents the picture of a large cohort of Italian patients with narcolepsy who were prescribed with pitolisant, suggesting that polytherapy is highly frequent to tailor a patient-centered approach.

Narcolepsy in Children: Sleep disorders in children, A rapidly evolving field seeking consensus

Narcolepsy is a life-long sleep disorder with two distinct subtypes, narcolepsy type I and narcolepsy type II. It is now well recognized that the loss of hypocretin neurons underlies the pathogenesis of narcolepsy type I, however, the pathogenesis of narcolepsy type II is currently unknown. Both genetic and environmental factors play an important role in the pathogenesis of narcolepsy. There is increasing evidence that autoimmune processes may play a critical role in the loss of hypocretin neurons. Infections especially streptococcus and influenza have been proposed as a potential trigger for the autoimmune-mediated mechanism. Several recent studies have shown increased cases of pediatric narcolepsy following the 2009 H1N1 pandemic. The increased cases in Europe seem to be related to a specific type of H1N1 influenza vaccination (Pandemrix), while the increased cases in China are related to influenza infection. Children with narcolepsy can have an unusual presentation at disease onset including complex motor movements which may lead to delayed diagnosis. All classic narcolepsy tetrads are present in only a small proportion of children. The diagnosis of narcolepsy is confirmed by either obtaining cerebrospinal fluid hypocretin or overnight sleep study with the multiple sleep latency test (MSLT). There are limitations of using MSLT in young children such that a negative MSLT test cannot exclude narcolepsy. HLA markers have limited utility in narcolepsy, but it may be useful in young children with clinical suspicion of narcolepsy. For management, both pharmacologic and non-pharmacologic treatments are important in the management of narcolepsy. Pharmacotherapy is primarily aimed to address excessive daytime sleepiness and REM-related symptoms such as cataplexy. In addition to pharmacotherapy, routine screening of behavioral and psychosocial issues is warranted to identify patients who would benefit from bio-behavior intervention.

Hypocretin-1 measurements in cerebrospinal fluid using radioimmunoassay: within and between assay reliability and limit of quantification

Study Objectives

The most sensitive and specific investigative method for the diagnosis of narcolepsy type 1 (NT1) is the determination of hypocretin-1 (orexin-A) deficiency (≤110 pg/mL) in cerebrospinal fluid using a radioimmunoassay (RIA). We aimed to assess the reliability of the Phoenix Pharmaceuticals hypocretin-1 RIA, by determining the lower limit of quantification (LLOQ), the variability around the cutoff of 110 pg/mL, and the inter- and intra-assay variability.

Methods

Raw data of 80 consecutive hypocretin-1 RIAs were used to estimate the intra- and inter-assay coefficient of variation (CV). The LLOQ was established and defined as the lowest converted concentration with a CV <25%; the conversion is performed using a harmonization sample which is internationally used to minimize variation between RIAs.

Results

The mean intra-assay CV was 4.7%, while the unconverted inter-assay CV was 28.3% (18.5% excluding 2 outliers) and 7.5% when converted to international values. The LLOQ was determined as 27.9 pg/mL. The intra-assay CV of RIAs with lower specific radioactive activity showed a median of 5.6% (n = 41, range 1.6%–17.0%), which was significantly higher than in RIAs with higher specific activity (n = 36; median 3.2%, range 0.4%–11.6%, p = .013). The CV around the 110 pg/mL cutoff was <7%.

Conclusions

Hypocretin-1 RIAs should always be harmonized using standard reference material. The specific activity of an RIA has a significant impact on its reliability, because of the decay of ¹²⁵I radioactivity. Values around the hypocretin-1 cut-off can reliably be measured. Hypocretin-1 concentrations below 28 pg/mL should be reported as “undetectable” when measured with the Phoenix Pharmaceuticals RIA.

Clinical Trial Information

This study is not registered in a clinical trial register, as it has a retrospective database design

Sleep Disorders in Traumatic Brain Injury

SUMMARY

Sleep disorders are common after traumatic brain injury (TBI). This study will review the spectrum and proposed mechanisms of TBI-associated sleep disorders and discuss the clinical approach to diagnosis and management of them. Disordered and fragmented sleep with insomnia and daytime sleepiness is very common after TBI. Sleep disruption contributes to morbidity and neurocognitive and neurobehavioral deficits and prolongs the recovery phase after injury. Early recognition and correction of these problems may limit the secondary effects of TBI and improve patient outcomes. Evaluating sleep disorders in TBI should be an important component of TBI assessment and management. Finally, newer research techniques for early diagnosis, prognosis, and improved outcomes after TBI will also be addressed.

The Impact of Sleep Pattern in School/Work Performance During the COVID-19 Home Quarantine in Patients With Narcolepsy

Objectives

Narcolepsy patients were observed improvements in their academic performance during the COVID-19 home quarantine. Therefore, we aim to investigate the influence of sleep behavioral changes on school/work performance in narcolepsy patients during the home quarantine.

Methods

Patients admitted to Shandong Provincial Qianfoshan Hospital from Jan 1, 2017 to Jan 1, 2021 who were diagnosed with narcolepsy were studied by online questionnaires in two different periods (during and 1 year after the COVID-19 home quarantine), including five aspects: (1) changes in school/work performance (percentile ranking in class/Sheehan Disability Scale 1, SDS1); (2) daytime functions; (3) clinical symptoms; (4) psychological moods; (5) medication situations.

Results

A total of 46 narcolepsy patients 34 (73.9%) narcolepsy type 1, 12 (26.1%) narcolepsy type 2 with average age of 20.76 ± 8.99 years and an equal number of age and gender matched control subjects were enrolled. During the COVID-19 home quarantine, the narcolepsy patients were found that they altered sleep patterns, including later get up time (P < 0.001), longer total sleep time (TST, P = 0.001), better sleep quality (PSQI, P = 0.001), and lower anxiety level (P = 0.005). Their school/work performance improved parallelly [with better percentile ranking (P = 0.001) and lower SDS1 scores (P = 0.002)]. The results of multiple linear stepwise regression analysis showed a linear regression relationship between TST [efficient (95%) −7.356 (−13.570 to 1.143)], SDS1 score [efficient (95%) 6.580 (2.346–10.815), P = 0.004] and the percentile ranking after adjusting for potential effects. Both the improvements of sleep behavior and school/work performance disappeared after the end of COVID-19 home quarantine. No similar fluctuation was found in the control group.

Discussion

Changes in sleep pattern during the COVID-19 home quarantine, such as longer sleep time and later wake-up time, can reduce the degree of daytime sleepiness and increase the degree of daytime wakefulness of narcolepsy patients, which can alleviate the impact of the disease on school/work performance.