Narcolepsy

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.

Increased Risk of New-Onset Hypertension in Patients With Narcolepsy Initiating Sodium Oxybate: A Real-World Study

OBJECTIVE

To compare intermediate-term risk of new-onset hypertension between normotensive patients with narcolepsy initiating sodium oxybate (SXB cohort) and those not initiating sodium oxybate (control cohort).

PATIENTS AND METHODS

This retrospective cohort study used MarketScan administrative claims data from January 1, 2014, to February 29, 2020. Eligible patients were 18 years of age or older with continuous enrollment (≥180 days before and after cohort entry), had one or more narcolepsy claims or a prescription fill for sodium oxybate, had no history of hypertension or antihypertensive medication use, and had no use of sodium oxybate within 13 months before cohort entry. Patients in the SXB and control cohorts were matched 1:2 for the propensity score to balance baseline characteristics. End points were (1) a composite of new-onset hypertension diagnosis or antihypertensive medication initiation and (2) new-onset hypertension diagnosis. Patients were monitored for 180 days, until outcome occurrence, sodium oxybate discontinuation (SXB cohort), or sodium oxybate initiation (control cohort). Risk per 100 patients was reported; differences were evaluated using logistic regression to estimate adjusted odds ratios (ORs) and 95% confidence intervals (CIs).

RESULTS

The SXB and control cohorts included 954 and 1908 patients, respectively. Risk of new-onset hypertension diagnosis or antihypertensive medication initiation was higher in the SXB cohort than in the control cohort (6.60 vs 4.20 per 100 patients; OR, 1.61; 95% CI, 1.15 to 2.27). Risk of a new-onset hypertension diagnosis only in the SXB cohort was 0.94 per 100 patients and 0.52 per 100 patients in the control cohort (OR, 1.81; 95% CI, 0.73 to 4.46).

CONCLUSION

In this study, sodium oxybate use was associated with a new-onset hypertension diagnosis or antihypertensive medication initiation in normotensive patients with narcolepsy.

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.

Psychiatric comorbidity in Danish patients with narcolepsy type 1, narcolepsy type 2, and idiopathic hypersomnia: a case-control study

Study Objectives

To examine the difference in psychiatric comorbidity of Danish patients with Narcolepsy type 1 (NT1), Narcolepsy type 2 (NT2), and idiopathic hypersomnia (IH).

Methods

Polysomnography (PSG), Multiple Sleep Latency Test (MSLT), and lumbar puncture were performed on 505 patients referred to a sleep clinic for diagnostic evaluation of hypersomnia. Diagnosis, clinical characteristics, electrophysiologic data, and cerebrospinal fluid hypocretin-1 (Csf-Hcrt-1) results were retrieved. Subsequently, the patients were identified in the Danish national health registers to collect information on psychiatric diagnoses and psychotropic medication use 10 years before the sleep disorder diagnosis. The prevalence of psychiatric comorbidities per hypersomnia group was compared to a 1:4 general population control group matched on age, gender, and educational level.

Results

A diagnosis of NT2 and IH was significantly associated with total psychiatric comorbidity compared to the matched controls but not NT1 (NT1: OR = 1.5; NT2: OR = 6.1; IH: OR = 5.2). NT1 was not significantly associated with any psychiatric disorder. NT2 was significantly associated with schizophrenia spectrum disorders (OR = 8.5), mood disorders (OR = 6.7), neurotic disorders (OR = 3.8), personality disorders (OR = 3.1), and behavioral and emotional disorders (OR = 4.3). IH was significantly associated with schizophrenia spectrum disorders (OR = 3.3), mood disorders (OR = 5.9), neurotic disorders (OR = 3.0), and behavioral and emotional disorders (OR = 4.0).

Conclusions

NT2 and IH had a close relationship to psychiatric disorders before diagnosis of their sleep disorder, while NT1 did not. This supports previous studies finding higher rates of psychiatric illness in patients with hypersomnia; however, it highlights the similarity between NT2 and IH. We believe this link to psychiatric disorders could play a role in the pathophysiology. Future studies evaluating the relation between hypersomnias of central origin and psychiatric diseases should include hypersomnia subclassifications to further the understanding of the differences in these disorders.

High-resolution HLA sequencing and hypocretin receptor 2 autoantibodies in narcolepsy type 1 and type 2

Narcolepsy is a sleep disorder caused by an apparent degeneration of orexin/hypocretin neurons in the lateral hypothalamic area and a subsequent decrease in orexin/hypocretin levels in the cerebrospinal fluid. Narcolepsy is classified into type 1 (NT1) and type 2 (NT2). While genetic associations in the human leukocyte antigen (HLA) region and candidate autoantibodies have been investigated in NT1 to imply an autoimmune origin, less is known about the pathogenesis in NT2. Twenty-six NT1 and 15 NT2 patients were included, together with control groups of 24 idiopathic hypersomnia (IH) patients and 778 general population participants. High-resolution sequencing was used to determine the alleles, the extended haplotypes, and the genotypes of HLA-DRB3, -DRB4, -DRB5, -DRB1, -DQA1, -DQB1, -DPA1, and -DPB1. Radiobinding assay was used to determine autoantibodies against hypocretin receptor 2 (anti-HCRTR2 autoantibodies). NT1 was associated with HLA-DRB5*01:01:01, -DRB1*15:01:01, -DQA1*01:02:01, -DQB1*06:02:01, -DRB5*01:01:01, -DRB1*15:01:01, -DQA1*01:02:01, -DQB1*06:02:01 (odds ratio [OR]: 9.15; p = 8.31 × 10-4) and HLA-DRB5*01:01:01, -DRB1*15:01:01, -DQA1*01:02:01, -DQB1*06:02:01, -DRB4*01:03:01, -DRB1*04:01:01, -DQA1*03:02//03:03:01, -DQB1*03:01:01 (OR: 23.61; p = 1.58 × 10-4) genotypes. Lower orexin/hypocretin levels were reported in the NT2 subgroup (n = 5) that was associated with the extended HLA-DQB1*06:02:01 haplotype (p = .001). Anti-HCRTR2 autoantibody levels were not different between study groups (p = .8524). We confirmed the previous association of NT1 with HLA-DQB1*06:02:01 extended genotypes. A subgroup of NT2 patients with intermediate orexin/hypocretin levels and association with HLA-DQB1*06:02:01 was identified, indicating a possible overlap between the two distinct narcolepsy subtypes, NT1 and NT2. Low anti-HCRTR2 autoantibody levels suggest that these receptors might not function as autoimmune targets in either NT1 or NT2.

Estimating the prevalence and clinical causality of obstructive sleep apnea in paediatric narcolepsy patients

BACKGROUND

Numerous risk factors in paediatric narcolepsy may predispose them to obstructive sleep apnea (OSA). The concurrent presence of OSA in these patients might lead to underdiagnosing narcolepsy. This research investigates the prevalence and potential causality between OSA and paediatric narcolepsy.

METHODS

A case-control study coupled with a two-sample Mendelian randomization (MR) analysis was employed to explore the prevalence and causal link between paediatric narcolepsy and OSA risk.

RESULTS

The case-control study revealed that paediatric narcolepsy patients are at an increased risk of OSA, with an Odds ratio (OR) of 4.87 (95% CI: 2.20-10.71; P < 0.001). The inverse-variance weighted (IVW) model further suggests a potential causal link between narcolepsy and OSA (IVW OR: 4.671, 95% CI: 1.925-11.290; P < 0.001). Additionally, sensitivity analysis confirmed these findings' reliability.

CONCLUSION

The findings highlight an elevated prevalence and genetic susceptibility to OSA among paediatric narcolepsy patients, underscoring the necessity for clinical screening of OSA. Continued research is essential to clarify the pathogenic mechanisms and develop potential treatments.

Narcolepsy and risk of traumatic injury: a population-based matched cohort study

STUDY OBJECTIVES

We evaluated the risk of traumatic injury in patients with narcolepsy compared to the general population.

METHODS

We conducted a population-based matched cohort study using a Japanese health insurance claims database. For each patient with narcolepsy, up to 5 individuals from the general population without narcolepsy were matched by variables such as sex, age, and cohort entry month. The primary outcome was traumatic injury, and the secondary outcome was fracture. The study population was followed for up to 5 years from the cohort entry date. We estimated crude incidence rates, adjusted incidence rate differences, adjusted hazard ratios, and their 95% confidence intervals (CIs) for study outcomes using crude and multivariable Poisson and Cox regression models.

RESULTS

We included 2,451 patients with narcolepsy (mean age, 30.3 years; male, 58.0%) and 10,591 matched individuals (mean age, 30.6 years; male, 58.4%). Crude incidence rate of traumatic injury was 11.4 per 100 person-years for patients with narcolepsy compared with 6.2 per 100 person-years for matched individuals (adjusted incidence rate difference, 6.2 excess events per 100 person-years [95% CI, 4.9-7.4]; adjusted hazard ratio, 1.8 [95% CI, 1.5-2.2]). Crude incidence rate of fracture was 2.3 per 100 person-years for patients with narcolepsy compared with 1.3 per 100 person-years for matched individuals (adjusted incidence rate difference, 1.2 excess events per 100 person-years [95% CI, 0.7-1.7]; adjusted hazard ratio, 1.7 [95% CI, 1.4-2.1]).

CONCLUSIONS

Narcolepsy was associated with increased risk of traumatic injury. For patients with narcolepsy, optimized approaches to injury prevention should be considered.

CITATION

Zheng Y, Fukasawa T, Masuda S, Takeuchi M, Kawakami K. Narcolepsy and risk of traumatic injury: a population-based matched cohort study. J Clin Sleep Med. 2024;20(10):1657-1662.

Weight Loss With Once-nightly Sodium Oxybate for the Treatment of Narcolepsy: Analysis From the Phase III Randomized study Evaluating the efficacy and SafeTy of a ONce nightly formulation of sodium oxybate (REST-ON) Trial

PURPOSE

Individuals with narcolepsy are more likely to be obese than the general population. Changes in weight-related measures with extended-release, once-nightly sodium oxybate (ON-SXB) and characteristics of participants with ≥5% weight loss were assessed in a Randomized study Evaluating the efficacy and SafeTy of a ONce nightly formulation of sodium oxybate (REST-ON) trial post hoc analysis.

METHODS

REST-ON (NCT02720744) was a Phase III, double-blind, placebo-controlled, multicenter, randomized clinical trial. Participants aged ≥16 years with narcolepsy type 1 (NT1) or NT2 received ON-SXB or placebo for 13 weeks (week 1, 4.5 g; weeks 2-3, 6 g; weeks 4-8, 7.5 g; and weeks 9-13, 9 g). Weight and body mass index were measured at baseline and study end.

FINDINGS

Weights were similar between groups at baseline (mean [SD]; ON-SXB, 81.2 [20.8] kg; N = 107 [NT1, n = 80; NT2, n = 27]; placebo, 82.1 [22.5] kg; N = 105 [NT1, n = 82; NT2, n = 23]). At week 13 (9 g), mean (SD) weight decreased 1.3 (3.6) kg with ON-SXB and increased 0.2 (2.6) kg with placebo; 17.8% (19/107; NT1, n = 14; NT2, n = 5) of participants receiving ON-SXB had ≥5% weight loss versus 3.8% receiving placebo (4/105; NT1, n = 3; NT2, n = 1; P = 0.001). At week 13, least squares mean (SE) body mass index change from baseline was ‒0.51 (0.13) kg/m2 with ON-SXB and 0.08 (0.13) kg/m2 with placebo (least squares mean difference [95% CI], -0.59 [-0.95 to -0.23] kg/m2; P = 0.001). Excessive daytime sleepiness improved for both groups with ON-SXB, the ≥5% weight-loss subgroup exhibited larger improvement in the Maintenance of Wakefulness Test and Epworth Sleepiness Scale versus the other subgroup (weight loss <5%, no change, or weight gain) (Maintenance of Wakefulness Test, P = 0.019; Epworth Sleepiness Scale score, P < 0.001).

IMPLICATIONS

Narcolepsy is often associated with obesity, which may increase cardiometabolic risks. ON-SXB, an effective treatment for excessive daytime sleepiness and cataplexy, may be preferred in overweight or obese individuals to provide a more tailored treatment approach.

CLINICALTRIALS

GOV IDENTIFIER

NCT02720744.

Disappearance and dissemination of sleep symptoms: the importance of sleep medicine expertise for psychiatry. A comment on Forbes et al

Commentary of 'Elemental psychopathology: distilling constituent symptoms and patterns of repetition in the diagnostic criteria of the DSM-5' Vincent P. Martin 1, Régis Lopez 2,3, Jean-Arthur Micoulaud-Franchi 4,5, Christophe Gauld 4,6,.

Identifying and reducing risks of neurological complications associated with vaccination

Vaccines protect against many infectious diseases, including some that can directly or indirectly cause nervous system damage. Serious neurological consequences of immunization are typically extremely rare, although they have the potential to jeopardize vaccination programmes, as demonstrated most recently during the COVID-19 pandemic. Neurologists have an important role in identifying safety signals at population and individual patient levels, as well as providing advice on the benefit-risk profile of vaccination in cohorts of patients with diverse neurological conditions. This article reviews the links between vaccination and neurological disease and considers how emerging signals can be evaluated and their mechanistic basis identified. We review examples of neurotropic infections with live attenuated vaccines, as well as neuroimmunological and neurovascular sequelae of other types of vaccines. We emphasize that such risks are typically dwarfed by neurological complications associated with natural infection and discuss how the risks can be further mitigated. The COVID-19 pandemic has highlighted the need to rapidly identify and minimize neurological risks of vaccination, and we review the structures that need to be developed to protect public health against these risks in the future.

Cardiovascular Risks in People With Narcolepsy: Expert Panel Consensus Recommendations

BACKGROUND

Observational and retrospective studies suggest that people with narcolepsy may have an increased prevalence of cardiovascular and cardiometabolic comorbidities and may be at greater risk for future cardiovascular events. An expert consensus panel was formed to establish agreement on the risk of hypertension and cardiovascular/cardiometabolic disease in people with narcolepsy and to develop strategies to mitigate these risks.

METHODS AND RESULTS

Experts in sleep medicine and cardiology were selected to participate in the panel. After reviewing the relevant literature, the experts identified key elements, drafted recommendation statements, and developed discussion points to provide supporting evidence for the recommendations. The draft and final recommendations were rated on a scale from 0 (not at all agree) to 4 (very much agree). All experts had an agreement rating of 4.0 for all 14 revised recommendation statements for patients with narcolepsy. These statements comprised 3 themes: (1) recognize the risk of hypertension and cardiovascular/cardiometabolic disease, (2) reduce the risk of hypertension and cardiovascular/cardiometabolic disease, and (3) reduce sodium intake to lower the risk of hypertension and cardiovascular disease.

CONCLUSIONS

These consensus recommendations are intended to increase awareness of potential cardiovascular/cardiometabolic risks in patients with narcolepsy for all clinicians. Early monitoring for, and prevention of, cardiovascular risks in this population are of great importance, especially as narcolepsy usually develops in adolescents and young adults, who will be exposed to adverse effects of the disease for decades. Prospective systematic studies are needed to determine association and causation of narcolepsy with cardiovascular/cardiometabolic disorders.

Association of lifestyle with sleep health in general population in China: a cross-sectional study

The concept of a healthy lifestyle is receiving increasing attention. This study sought to identify an optimal healthy lifestyle profile associated with sleep health in general population of China. An online cross-sectional survey was conducted from June to July 2022. Six healthy lifestyle factors were assessed: healthy diet, regular physical exercise, never smoking, never drinking alcohol, low sedentary behavior, and normal weight. Participants were categorized into the healthy lifestyle (5-6 factors), average (3-4 factors), and unhealthy lifestyle groups (0-2 factors). The study's primary outcome was sleep health, which included sleep quality, duration, pattern, and the presence of any sleep disorder or disturbance, including insomnia, excessive daytime sleepiness, obstructive apnea syndrome, and narcolepsy. Multivariable logistic regression analysis was applied to explore lifestyles associated with the selected sleep health outcomes. 41,061 individuals were included, forming 18.8% healthy, 63.8% average, and 17.4% unhealthy lifestyle groups. After adjusting for covariates, participants with healthy lifestyle were associated with a higher likelihood of good sleep quality (OR = 1.56, 95% CI = 1.46-1.68), normal sleep duration (OR = 1.60, 95% CI = 1.49-1.72), healthy sleep pattern (OR = 2.15, 95% CI = 2.00-2.31), and lower risks of insomnia (OR = 0.66, 95% CI = 0.61-0.71), excessive daytime sleepiness (OR = 0.66, 95% CI = 0.60-0.73), and obstructive apnea syndrome (OR = 0.40, 95% CI = 0.37-0.43), but not narcolepsy (OR = 0.92, 95% CI = 0.83-1.03), compared to those with unhealthy lifestyle. This large cross-sectional study is the first to our knowledge to quantify the associations of a healthy lifestyle with specific aspects of sleep health. The findings offer support for efforts to improve sleep health by modulating lifestyle.

Out-of-body experiences in relation to lucid dreaming and sleep paralysis: A theoretical review and conceptual model

Out-of-body experiences (OBEs) are characterized by the subjective experience of being located outside the physical body. Little is known about the neurophysiology of spontaneous OBEs, which are often reported by healthy individuals as occurring during states of reduced vigilance, particularly in proximity to or during sleep (sleep-related OBEs). In this paper, we review the current state of research on sleep-related OBEs and hypothesize that maintaining consciousness during transitions from wakefulness to REM sleep (sleep-onset REM periods) may facilitate sleep-related OBEs. Based on this hypothesis, we propose a new conceptual model that potentially describes the relationship between OBEs and sleep states. The model sheds light on the phenomenological differences between sleep-related OBEs and similar states of consciousness, such as lucid dreaming (the realization of being in a dream state) and sleep paralysis (feeling paralyzed while falling asleep or waking up), and explores the potential polysomnographic features underlying sleep-related OBEs. Additionally, we apply the predictive coding framework and suggest a connecting link between sleep-related OBEs and OBEs reported during wakefulness.

Knowledge of Narcolepsy Among Physicians in Makkah Region, Saudi Arabia: A Cross-Sectional Study

Background Narcolepsy is a chronic sleep disorder that is characterized by excessive daytime sleepiness and cataplexy. It has been increasingly diagnosed over the years, impacting productivity and employment rates. Awareness of healthcare providers is crucial for the early identification and management of this condition. Objectives This study assessed physicians' knowledge of narcolepsy in the Makkah region of Saudi Arabia. Method This cross-sectional study was conducted from February to November 2023. An online self-administered questionnaire has been used to target physicians working in the Makkah region of Saudi Arabia. The utilized questionnaire assessed demographic and professional data as well as the participants' knowledge of narcolepsy. Statistical analysis was performed using RStudio (R version 4.3.1.). Statistical differences in knowledge were assessed using Pearson's chi-squared and Fisher's exact tests. Factors associated with knowledge of narcolepsy were investigated through univariable and multivariable regression analyses expressed using beta coefficients and 95% confidence intervals (95% CIs). Statistical significance was considered at p < 0.05. Results A total of 226 physicians participated in this study. Male physicians (54.4%, n = 123), practicing in governmental hospitals (77.9%, n = 176) and residing in Makkah City (43.4%, n = 98) were predominant. Non-surgical specialties represented 73.5% (n = 166) of the sample. Around 81% (n = 184) of the participants were aware of narcolepsy, with a significant difference according to professional status (p = 0.045). The majority of physicians have correctly identified narcolepsy as a sleep disorder (78.3%, n = 177), but only 32.3% (n = 73) have identified its typical onset age group and recognized that there are two types of narcolepsy. Almost half of the respondents indicated a lack of knowledge about the diagnostic criteria for narcolepsy in the DSM-5 (52.2%, n = 118). Only 27.4% (n = 62) recognized the correct diagnostic criteria. Half of the sample (51.3%, n = 116) recognized the use of multiple sleep latency tests for the diagnosis. For factors associated with higher participants' knowledge, non-surgical specialties showed significantly higher knowledge scores compared to surgical specialties (beta = 0.91, 95% CI, 0.13 to 1.7, p = 0.024). Conclusion This study has revealed a significant lack of knowledge about narcolepsy among physicians in Makkah region. This raises concerns about the timely identification, proper understanding, and accurate diagnosis of patients with narcolepsy. Adequate understanding of narcolepsy is crucial to avoid its misdiagnosis or delays in receiving appropriate treatment and support, ultimately impacting their quality of life.

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.

Disadvantaged social status contributed to sleep disorders: An observational and genome-wide gene-environment interaction analysis

BACKGROUND

Sleep is a natural and essential physiological need for individuals. Our study aimed to research the associations between accumulated social risks and sleep disorders.

METHODS

In this study, we came up with a polysocial risk score (PsRS), which is a cumulative social risk index composed of 13 social determinants of health. This research includes 239,165 individuals with sleep disorders and social determinants of health data from the UK Biobank cohort. First, logistic regression models were performed to examine the associations of social determinants of health and sleep disorders, including chronotype, narcolepsy, insomnia, snoring, short and long sleep duration. Then, PsRS was calculated based on statistically significant social determinants of health for each sleep disorder. Third, a genome-wide gene-environment interaction study was conducted to explore the interactions between single-nucleotide polymorphisms and PsRS in relation to sleep disorders.

RESULTS

Higher PsRS scores were associated with worse sleep status, with the adjusted odds ratio (OR) ranging from 1.10 (95% Confidence interval [CI]: 1.09-1.11) to 1.29 (95% CI: 1.27-1.30) for sleep disorders. Emotional stress (OR = 1.36, 95% CI: 1.28-1.43) and not in paid employment (OR = 2.62, 95% CI: 2.51-2.74) were found to have significant contributions for sleep disorders. Moreover, multiple single-nucleotide polymorphisms were discovered to have interactions with PsRS, such as FRAS1 (P = 2.57 × 10-14) and CACNA1A (P = 8.62 × 10-14) for narcolepsy, and ACKR3 (P = 1.24 × 10-8) for long sleep.

CONCLUSIONS

Our findings suggested that cumulative social risks was associated with sleep disorders, while the interactions between genetic susceptibility and disadvantaged social status are risk factors for the development of sleep disorders.

Serum N-Glycan Profiling of Patients with Narcolepsy Type 1 Using LC-MS/MS

The neurological condition known as narcolepsy type 1 (NT1) is an uncommon condition marked by extreme daytime sleepiness, cataplexy, sleep paralysis, hallucinations, disrupted nocturnal sleep, and low or undetectable levels of orexin in the CSF fluid. NT1 has been hypothesized to be an immunological disorder; its treatment is currently only symptomatic, and misdiagnosis is not uncommon. This study compares the N-glycome of NT1 patients with healthy controls in search of potential glycan biomarkers using LC-MS/MS. A total of 121 candidate N-glycans were identified, 55 of which were isomeric N-glycan structures and 65 were not. Seventeen N-glycan biomarker candidates showed significant differences between the NT1 and control cohorts. All of the candidate glycan biomarkers were isomeric except HexNAc6Hex7Fuc0NeuAc1 (6701) and HexNAc6Hex7Fuc1NeuAc2 (6712). Therefore, with isomeric and nonisomeric structures, a total of 20 candidate N-glycan biomarkers are reported in this study, and interestingly, all are either sialylated or sialylated-fucosylated and upregulated in NT1 relative to the control. The distribution levels of all the identified N-glycans show that the sialylated glycan type is the most abundant in NT1 and is majorly disialylated, although the trisialylated subtype is three-fold higher in NT1 compared to the healthy control. The first isomers of HexNAc5Hex6Fuc0NeuAc3 (5603), HexNAc6Hex7Fuc0NeuAc2 (6702), and HexNAc6Hex7Fuc1NeuAc4 (6714) expressed a high level of fold changes (FC) of 1.62, 2.19, and 2.98, respectively. These results suggest a different N-glycome profile of NT1 and a relationship between sialylated glycan isomers in NT1 disease development or progression. The revelation of N-glycan expression alterations in this study may improve NT1 diagnostic methods, understanding of NT1 pathology, and the development of new targeted therapeutics.

Narcolepsy and rapid eye movement sleep

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

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.

The nature and magnitude of cognitive impairment in narcolepsy type 1, narcolepsy type 2, and idiopathic hypersomnia: a meta-analysis

People with narcolepsy type 1 (NT1), narcolepsy type 2 (NT2), and idiopathic hypersomnia (IH) often report cognitive impairment which can be quite burdensome but is rarely evaluated in routine clinical practice. In this systematic review and meta-analysis, we assessed the nature and magnitude of cognitive impairment in NT1, NT2, and IH in studies conducted from January 2000 to October 2022. We classified cognitive tests assessing memory, executive function, and attention by cognitive domain. Between-group differences were analyzed as standardized mean differences (Cohen's d), and Cohen's d for individual tests were integrated according to cognitive domain and clinical disease group. Eighty-seven studies were screened for inclusion; 39 satisfied inclusion criteria, yielding 73 comparisons (k): NT1, k = 60; NT2, k = 8; IH, k = 5. Attention showed large impairment in people with NT1 (d = -0.90) and IH (d = -0.97), and moderate impairment in NT2 (d = -0.60). Executive function was moderately impaired in NT1 (d = -0.30) and NT2 (d = -0.38), and memory showed small impairments in NT1 (d = -0.33). A secondary meta-analysis identified sustained attention as the most impaired domain in NT1, NT2, and IH (d ≈ -0.5 to -1). These meta-analyses confirm that cognitive impairments are present in NT1, NT2, and IH, and provide quantitative confirmation of reports of cognitive difficulties made by patients and clinicians. These findings provide a basis for the future design of studies to determine whether cognitive impairments can improve with pharmacologic and nonpharmacologic treatments for narcolepsy and IH.

The Changed Nocturnal Sleep Structure and Higher Anxiety, Depression, and Fatigue in Patients with Narcolepsy Type 1

Purpose

This study aimed to evaluate nocturnal sleep structure and anxiety, depression, and fatigue in patients with narcolepsy type 1 (NT1).

Methods

Thirty NT1 patients and thirty-five healthy controls were enrolled and evaluated using the Epworth sleepiness scale (ESS), Generalized Anxiety Disorder-7, Patient Health Questionnaire-9, Fatigue Severity Scale (FSS), polysomnography, multiple sleep latency test, and brain function state monitoring. Statistical analyses were performed using SPSS Statistics for Windows, version 23.0. Benjamini-Hochberg correction was performed to control the false discovery rate.

Results

Apart from typical clinical manifestations, patients with NT1 are prone to comorbidities such as nocturnal sleep disorders, anxiety, depression, and fatigue. Compared with the control group, patients with NT1 exhibited abnormal sleep structure, including increased total sleep time (P adj=0.007), decreased sleep efficiency (P adj=0.002), shortening of sleep onset latency (P adj<0.001), elevated wake after sleep onset (P adj=0.002), increased N1% (P adj=0.006), and reduced N2%, N3%, and REM% (P adj=0.007, P adj<0.001, P adj=0.013). Thirty-seven percent of patients had moderate to severe obstructive sleep apnea-hypopnea syndrome. And sixty percent of patients were complicated with REM sleep without atonia. Patients with NT1 displayed increased anxiety propensity (P adj<0.001), and increased brain fatigue (P adj=0.020) in brain function state monitoring. FSS scores were positively correlated with brain fatigue (P adj<0.001) and mean sleep latency was inversely correlated with FSS scores and brain fatigue (P adj=0.013, P adj=0.029). Additionally, ESS scores and brain fatigue decreased after 3 months of therapy (P=0.012, P=0.030).

Conclusion

NT1 patients had abnormal nocturnal sleep structures, who showed increased anxiety, depression, and fatigue. Excessive daytime sleepiness and fatigue improved after 3 months of treatment with methylphenidate hydrochloride prolonged-release tablets in combination with venlafaxine.

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.

Homozygous HLA-DQB1*06:02 combined with T-cell receptor alpha polymorphism results in narcolepsy onset - A familial case report

Narcolepsy is a life-long neurological disorder with well-established genetic risk factors. Human leukocyte antigen-DQB1*06:02 remains the strongest genetic predeterminant; however, polymorphisms in genes encoding the T-cell receptor alpha chain are also strongly linked. This case report shows the inheritance pathway of these genetic markers contributing to narcolepsy onset in a 17-year-old female.

Accidental calcium, magnesium, potassium and sodium oxybates (Xywave) overdose: mistiming of a single night's narcolepsy medication leading to respiratory failure requiring mechanical ventilation

While typically thought of as an illicit substance, oxybate salts or gamma-hydroxybutyrate (GHB) has more recently been prescribed to treat narcolepsy by enhancing night-time sleep resulting in decreased daytime drowsiness. This case involves a college-aged female with prescribed GHB for narcolepsy who took her second nightly dose too early. This resulted in mental depression, respiratory failure, intubation and mechanical ventilation. The patient was successfully extubated in the intensive care unit several hours later with no residual morbidity. We were unable to identify any prior reports of mixed-salt oxybate toxicity following mistimed drug administration. This case should serve as a warning to emergency physicians to be on the lookout for GHB as part of the differential diagnosis for patients with narcolepsy presenting with altered mental status. It should also serve as a warning to patients and prescribers that this medication can have outcomes that require immediate medical intervention.

Clinical analysis and literature review of two paediatric cases of anti-IgLON5 antibody-related encephalitis

Introduction

Anti-IgLON5 antibody-related encephalitis is a rare autoimmune disorder of the central nervous system, predominantly occurring in middle-aged elderly individuals, with paediatric cases being exceptionally rare. This study aims to enhance the understanding of paediatric anti-IgLON5 antibody-related encephalitis by summarising its clinical and therapeutic characteristics.

Method

A retrospective analysis was conducted on two paediatric patients diagnosed with anti-IgLON5 antibody-related encephalitis at Hunan Children's Hospital from August 2022 to November 2023. This involved reviewing their medical records and follow-up data, in addition to a literature review.

Results

The study involved two patients, one male and one female, aged between 2.5 and 9.6 years, both presenting with an acute/subacute course of illness. Clinically, both exhibited movement disorders (including dystonia, involuntary movements, and ataxia), cognitive impairments, sleep disturbances, and psychiatric symptoms. Patient 1 experienced epileptic seizures, while Patient 2 exhibited brainstem symptoms and abnormal eye movements. Neither patient showed autonomic dysfunction. Patient 1 had normal cerebrospinal fluid (CSF) and Brain MRI findings, whereas Patient 2 showed moderate leukocytosis and mild protein elevation in the CSF, and Brain MRI revealed symmetrical lesions in the basal ganglia and cerebellum. Oligoclonal bands in the CSF were positive in both cases. Both patients tested negative for HLA-DQB*05:01 and HLA-DRB*10:01. They received both first-line and second-line immunotherapies, with Patient 2 showing a poor response to treatment.

Discussion

Paediatric cases of anti-IgLON5 antibody-related encephalitis similarly present sleep disturbances as a core symptom, alongside various forms of movement disorders. Immunotherapy is partially effective. Compared to adult patients, these paediatric cases tend to exhibit more pronounced psychiatric symptoms, a more rapid onset, and more evident inflammatory changes in the CSF. The condition appears to have a limited association with HLA-DQB*05:01 and HLA-DRB*10:01 polymorphisms.

Orexins and primary headaches: an overview of the neurobiology and clinical impact

INTRODUCTION

Primary headaches, including migraines and cluster headaches, are highly prevalent disorders that significantly impact quality of life. Several factors suggest a key role for the hypothalamus, including neuroimaging studies, attack periodicity, and the presence of altered homeostatic regulation. The orexins are two neuropeptides synthesized almost exclusively in the lateral hypothalamus with widespread projections across the central nervous system. They are involved in an array of functions including homeostatic regulation and nociception, suggesting a potential role in primary headaches.

AREAS COVERED

This review summarizes current knowledge of the neurobiology of orexins, their involvement in sleep-wake regulation, nociception, and functions relevant to the associated symptomology of headache disorders. Preclinical reports of the antinociceptive effects of orexin-A in preclinical models are discussed, as well as clinical evidence for the potential involvement of the orexinergic system in headache.

EXPERT OPINION

Several lines of evidence support the targeted modulation of orexinergic signaling in primary headaches. Critically, orexins A and B, acting differentially via the orexin 1 and 2 receptors, respectively, demonstrate differential effects on trigeminal pain processing, indicating why dual-receptor antagonists failed to show clinical efficacy. The authors propose that orexin 1 receptor agonists or positive allosteric modulators should be the focus of future research.

Identification of bidirectional causal links between gut microbiota and narcolepsy type 1 using Mendelian randomization

STUDY OBJECTIVES

Narcolepsy type 1 (NT1), characterized by cataplexy and orexin deficiency, is a rare and frequently debilitating neurological disorder. It has been noted to have connections with the gut microbiota, yet the exact causal relationships remain unclear.

METHODS

We conducted a comprehensive bidirectional Mendelian randomization (MR) study to rigorously investigate the causal links between the gut microbiota and NT1, utilizing genetic datasets from the MiBioGen consortium and FinnGen consortium, respectively. The inverse-variance weighted (IVW) method was employed to obtain the primary MR estimates, supplemented by several alternative methods as well as sensitivity analyses including Cochran's Q, MR-Egger, MR pleiotropy residual sum and outlier, leave-one-out, and genetic colocalization.

RESULTS

Our findings indicated that an increased relative abundance of five genera including Blautia (p = 4.47E-5), Collinsella (p = 0.036), Gordonibacter (p = 0.047), Hungatella (p = 0.015), and Lachnospiraceae UCG010 (p = 0.027) may be associated with a decreased risk of NT1. Conversely, an increased relative abundance of class Betaproteobacteria (p = 0.032), genus Alloprevotella (p = 0.009), and genus Ruminiclostridium6 (p = 0.029) may potentially heighten the risk of NT1. The onset of NT1 may lead to a decrease in the relative abundance of genus Eubacterium eligens group (p = 0.022), while a increase in the family Family XI (p = 0.009), genus Hungatella (p = 0.005), genus Prevotella (p = 0.013), and unknown genus id.2001 (p = 0.019). These findings remained robust under all sensitivity analyses.

CONCLUSIONS

Our results offer robust evidence for the bidirectional causal links between particular gut microbial taxa and NT1, underscoring the significance of the microbiota-gut-brain axis in the pathological process of NT1.

The Burden of Narcolepsy in Adults: A Population Sampling Study Using Personal Media

OBJECTIVE

To obtain insight in the spectrum of narcolepsy symptoms and associated burden in a large cohort of patients.

METHODS

We used the Narcolepsy Monitor, a mobile app, to easily rate the presence and burden of 20 narcolepsy symptoms. Baseline measures were obtained and analyzed from 746 users aged between 18 and 75 years with a reported diagnosis of narcolepsy.

RESULTS

Median age was 33.0 years (IQR 25.0-43.0), median Ullanlinna Narcolepsy Scale 19 (IQR 14.0-26.0), 78% reported using narcolepsy pharmacotherapy. Excessive daytime sleepiness (97.2%) and lack of energy were most often present (95.0%) and most often caused a high burden (79.7% and 76.1% respectively). Cognitive symptoms (concentration 93.0%, memory 91.4%) and psychiatric symptoms (mood 76.8%, anxiety/panic 76.4%) were relatively often reported to be present and burdensome. Conversely, sleep paralysis and cataplexy were least often reported as highly bothersome. Females experienced a higher burden for anxiety/panic, memory, and lack of energy.

CONCLUSIONS

This study supports the notion of an elaborate narcolepsy symptom spectrum. Each symptom's contribution to the experienced burden varied, but lesser-known symptoms did significantly add to this as well. This emphasizes the need to not only focus treatment on the classical core symptoms of narcolepsy.

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.

Association between cytokines and fatigue in patients with type 1 narcolepsy

BACKGROUND

Fatigue is a frequent complaint among patients with narcolepsy. Studies have shown that inflammatory cytokines are associated with fatigue in neurological disorders; however, this association has not been identified in patients with type 1 narcolepsy. The purpose of this study was to investigate the potential relationship between cytokines and fatigue in patients with type 1 narcolepsy.

METHODS

We investigated the association between 12 inflammatory cytokines and fatigue in 49 patients with type 1 narcolepsy. The Multidimensional Fatigue Inventory-20 was used to assess the fatigue severity. The associations of fatigue were identified using Spearman and Pearson correlation analyses. A linear regression analysis model was used to adjust the confounding factors and evaluate the associations of fatigue.

RESULTS

Correlation analysis showed that the plasma interleukin (IL)-2 level (r = 0.409, p = 0.004) was positively correlated with fatigue in patients with narcolepsy type 1. After adjusting for confounding factors, the linear regression model revealed a positive association between the IL-2 level (β = 1.148, p = 0.04) and fatigue in individuals diagnosed with type 1 narcolepsy.

CONCLUSION

IL-2 levels show a positive correlation with fatigue in type 1 narcolepsy, suggesting its potential role in the pathophysiology of fatigue.

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.

A series of 7 cases of patients with narcolepsy with hypocretin deficiency without the HLA DQB1*06:02 allele

STUDY OBJECTIVES

We report data collected from 2 reference European sleep centers on a series of patients with narcolepsy with hypocretin-1 deficiency and absence of the human leukocyte antigens (HLA) DQB1*06:02 allele.

METHODS

Clinical data, HLA DQ markers, and cerebrospinal fluid assessments were collected retrospectively from Caucasian patients with a diagnosis of narcolepsy type 1 with cerebrospinal fluid hypocretin-1 deficiency (< 110 pg/ml) and absence of the HLA DQB1*06:02 allele, with follow-up with at least 1 visit within the last 4 years, consecutively admitted to 2 European sleep centers (Lugano, Switzerland and Montpellier, France).

RESULTS

Seven patients (3 of 29 patients in Lugano and 4 of 328 in Montpellier) were diagnosed with narcolepsy with hypocretin-1 deficiency and absence of HLA DQB1*06:02 (ie, 2% of patients with narcolepsy type 1). Regarding the HLA-DQB1 genotyping, 4 cases were positive for HLA DQB1*03:01, 1 for DQB1*03:02, and 3 for DQB1*02:01. Three patients had atypical cataplexy and 1 had no cataplexy. Only 2 patients had both a mean sleep latency of less than 8 minutes and more than 2 sleep onset rapid eye movement periods on the Multiple Sleep Latency Test, indicative of a less severe condition.

CONCLUSIONS

Although rare, this series of 7 cases confirms that hypocretin-deficient narcolepsy should not be excluded in the absence of HLA DQB1*06:02, especially if patients are carriers of other high-risk HLA-DQB1 alleles (DQB1*03:01, *03:02, *02:01). These data support the hypothesis that narcolepsy type 1 is a wider disease spectrum linked to the loss of hypocretin peptide.

CITATION

Miano S, Barateau L, De Pieri M, et al. A series of 7 cases of patients with narcolepsy with hypocretin deficiency without the HLA DQB1*06:02 allele. J Clin Sleep Med. 2023;19(12):2053-2057.

Early- and late-onset narcolepsy: possibly two distinct clinical phenotypes

PURPOSE

To investigate the clinical characteristics and the risk factors associated with excessive daytime sleepiness (EDS) in patients with early- and late-onset narcolepsy.

METHODS

Patients with narcolepsy were consecutively recruited. All patients were separated into early- and late-onset groups according to the onset age of disease ≤ 15 and > 15 years, respectively. Demographic, clinical, and sleep parameters were compared between the two groups. Linear regressions were performed to examine the risk factors of subjective and objective EDS in patients with early- and late-onset narcolepsy.

RESULTS

A total of 101 patients with narcolepsy (median age at recruitment = 18.0 years) were classified into an early-onset group (67 patients with median age at onset = 12.0 years) and a late-onset group (34 patients with median age at onset = 28.5 years). Compared with early-onset group, late-onset group scored significantly higher on Epworth Sleepiness Scale (ESS), Ullanlinna Narcolepsy Scale (UNS), sleep paralysis, rapid eye movement (REM) sleep behavior disorder (RBD) questionnaire-Hong Kong (all P < 0.050). UNS-cataplexy and sleep paralysis had significantly positive associations with subjective EDS, and N1%, arousal index, and periodic limb movements index were positively associated with objective EDS in the early-onset group (all P < 0.050). However, these associations were not observed in late-onset narcolepsy.

CONCLUSION

Late onset narcolepsy had more severe self-reported narcolepsy symptoms. REM sleep related symptoms and disrupted nighttime sleep were associated with EDS in early-onset narcolepsy. These findings suggest that early- and late-onset narcolepsy may represent two distinct phenotypes.

Harriet Tubman's Hypersomnia: Insights from Historical and Medical Perspectives

Harriet Tubman, a hero of the abolitionist movement and early civil rights advocate, suffered a head injury in childhood and subsequently developed sleep attacks associated with visions that were extensively documented in historical accounts. Her contemporaries perceived these visions together with unpredictable and unavoidable urges to sleep as manifestations of her deep faith, rather than as symptoms of an illness. While religious perspectives remain crucial to understanding Tubman's sleep-related experiences, some may consider them insufficient in view of modern medical advances. We propose the parallel explanation that her sleep attacks, usually attributed to temporal lobe epilepsy, actually represent a hypersomnia that is most consistent with the modern diagnosis of post-traumatic narcolepsy. Using historical analysis as well as current understandings of sleep medicine, we aim to shed light on this under-recognized aspect of Tubman's life. In addition, this case study allows us to review the potential long-term effects of severe traumatic brain injuries; consider a differential for excessive daytime sleepiness and hypnagogic hallucinations; and familiarize readers with the pathophysiology, diagnosis, and treatment of narcolepsy. Whether her symptoms are viewed through the lens of the past or measured against current biomedical standards, Tubman demonstrated an inspiring ability to persevere despite intrusive sleep episodes and to realize her dreams for the betterment of others.

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.

Causal relationship between narcolepsy and depression: A two-sample Mendelian randomization study

OBJECTIVE

While numerous studies have highlighted an increased prevalence of depression in individuals with narcolepsy, their conclusions are often clouded by potential confounding factors, leaving the causal relationship uncertain. This study posits that narcolepsy might heighten the risk of depression and employs a two-sample Mendelian randomization analysis to investigate this hypothesis.

METHODS

Summary statistics were obtained from genome-wide association studies databases and performed a two-sample MR analysis. The inverse-variance weighted method was employed as the primary approach to evaluate causality. Additionally, supplementary methods were conducted, including MR-Egger, simple median, maximum likelihood, weighted median, penalized weighted median, and weighted mode, to complement the IVW results. Finally, sensitivity analyses were undertaken to assess heterogeneity, horizontal pleiotropy, and stability of the results.

RESULTS

The inverse-variance weighted analysis revealed an odds ratio of 1.055 with a 95% confidence interval of 1.015 to 1.097, indicating a significant positive association between narcolepsy and depression. Although significant heterogeneity was observed (Q = 56.22, p = 0.0005), no evidence of horizontal pleiotropy was detected (intercept = -0.00027, p = 0.69). Results from the additional methods were in agreement with those obtained from the inverse-variance weighted analysis. The reverse causality of depression on narcolepsy was not detected (p = 0.11).

CONCLUSION

This study suggests a potential causal association between narcolepsy and depression. While the findings offer insights into this relationship, they should be interpreted with caution, especially considering the limitations of the data. Further research is needed to better understand the underlying mechanisms and to explore potential interventions.

Efficacy of once-nightly sodium oxybate (FT218) in narcolepsy type 1 and type 2: post hoc analysis from the Phase 3 REST-ON Trial

STUDY OBJECTIVES

Post hoc analyses from the phase 3 REST-ON trial evaluated efficacy of extended-release once-nightly sodium oxybate (ON-SXB; FT218) vs placebo for daytime sleepiness and disrupted nighttime sleep in narcolepsy type 1 (NT1) and 2 (NT2).

METHODS

Participants were stratified by narcolepsy type and randomized 1:1 to ON-SXB (4.5 g, week 1; 6 g, weeks 2-3; 7.5 g, weeks 4-8; and 9 g, weeks 9-13) or placebo. Assessments included mean sleep latency on Maintenance of Wakefulness Test (MWT) and Clinical Global Impression-Improvement (CGI-I) rating (coprimary endpoints) and sleep stage shifts, nocturnal arousals, and patient-reported sleep quality, refreshing nature of sleep, and Epworth Sleepiness Scale (ESS) score (secondary endpoints) separately in NT1 and NT2 subgroups.

RESULTS

The modified intent-to-treat population comprised 190 participants (NT1, n = 145; NT2, n = 45). Significant improvements were demonstrated with ON-SXB vs placebo in sleep latency for NT1 (all doses, p < .001) and NT2 (6 and 9 g, p < .05) subgroups. Greater proportions of participants in both subgroups had CGI-I ratings of much/very much improved with ON-SXB vs placebo. Sleep stage shifts and sleep quality significantly improved in both subgroups (all doses vs placebo, p < .001). Significant improvements with all ON-SXB doses vs placebo in refreshing nature of sleep (p < .001), nocturnal arousals (p < .05), and ESS scores (p ≤ .001) were reported for NT1 with directional improvements for NT2.

CONCLUSIONS

Clinically meaningful improvements of a single ON-SXB bedtime dose were shown for daytime sleepiness and DNS in NT1 and NT2, with less power for the limited NT2 subgroup.

Larger hypothalamic volume in narcolepsy type 1

STUDY OBJECTIVES

Narcolepsy type 1 (NT1) is a neurological sleep disorder. Postmortem studies have shown 75%-90% loss of the 50 000-70 000 hypocretin-producing neurons and 64%-94% increase in the 64 000-120 000 histaminergic neurons and conflicting indications of gliosis in the hypothalamus of NT1 patients. The aim of this study was to compare MRI-based volumes of the hypothalamus in patients with NT1 and controls in vivo.

METHODS

We used a segmentation tool based on deep learning included in Freesurfer and computed the volume of the whole hypothalamus, left/right part of the hypothalamus, and 10 hypothalamic subregions. We included 54 patients with post-H1N1 NT1 (39 females, mean age 21.8 ± 11.0 years) and 114 controls (77 females, mean age 23.2 ± 9.0 years). Group differences were tested with general linear models using permutation testing in Permutation Analysis of Linear Models and evaluated after 10 000 permutations, yielding two-tailed P-values. Furthermore, a stepwise Bonferroni correction was performed after dividing hypothalamus into smaller regions.

RESULTS

The analysis revealed larger volume for patients compared to controls for the whole hypothalamus (Cohen's d = 0.71, p = 0.0028) and for the left (d = 0.70, p = 0.0037) and right part of the hypothalamus (d = 0.65, p = 0.0075) and left (d = 0.72, p = 0.0036) and right tubular-inferior (d = 0.71, p = 0.0037) hypothalamic subregions.

CONCLUSIONS

In conclusion, patients with post-H1N1 NT1 showed significantly larger hypothalamic volume than controls, in particular in the tubular-inferior subregions which could reflect several processes as previous studies have indicated neuroinflammation, gliosis, and changes in the numbers of different cell types.

LC-MS/MS Quantitation of HILIC-Enriched N-glycopeptides Derived from Low-Abundance Serum Glycoproteins in Patients with Narcolepsy Type 1

Glycoproteomic analysis is always challenging because of low abundance and complex site-specific heterogeneity. Glycoproteins are involved in various biological processes such as cell signaling, adhesion, and cell-cell communication and may serve as potential biomarkers when analyzing different diseases. Here, we investigate glycoproteins in narcolepsy type 1 (NT1) disease, a form of narcolepsy characterized by cataplexy-the sudden onset of muscle paralysis that is typically triggered by intense emotions. In this study, 27 human blood serum samples were analyzed, 16 from NT1 patients and 11 from healthy individuals serving as controls. We quantified hydrophilic interaction liquid chromatography (HILIC)-enriched glycopeptides from low-abundance serum samples of controls and NT1 patients via LC-MS/MS. Twenty-eight unique N-glycopeptides showed significant changes between the two studied groups. The sialylated N-glycopeptide structures LPTQNITFQTESSVAEQEAEFQSPK HexNAc6, Hex3, Neu5Ac2 (derived from the ITIH4 protein) and the structure IVLDPSGSMNIYLVLDGSDSIGASNFTGAK HexNAc5, Hex4, Fuc1 (derived from the CFB protein), with p values of 0.008 and 0.01, respectively, were elevated in NT1 samples compared with controls. In addition, the N-glycopeptide protein sources Ceruloplasmin, Complement factor B, and ITH4 were observed to play an important role in the complement activation and acute-phase response signaling pathways. This may explain the possible association between the biomarkers and pathophysiological effects.

Serum metabolomics study of narcolepsy type 1 based on ultra-performance liquid chromatography-tandem mass spectrometry

Narcolepsy is a chronic and underrecognized sleep disorder characterized by excessive daytime sleepiness and cataplexy. Furthermore, narcolepsy type 1 (NT1) has serious negative impacts on an individual's health, society, and the economy. Currently, many sleep centers lack the means to measure orexin levels in the cerebrospinal fluid. We aimed to analyze the characteristics of metabolite changes in patients with NT1, measured by ultra-performance liquid chromatography-tandem mass spectrometry. A principal component analysis (PCA), an orthogonal partial least square discriminant analysis (OPLS-DA), t tests, and volcano plots were used to construct a model of abnormal metabolic pathways in narcolepsy. We identified molecular changes in serum specimens from narcolepsy patients and compared them with control groups, including dehydroepiandrosterone, epinephrine, N-methyl-D-aspartic acid, and other metabolites, based on an OPLS-loading plot analysis. Nine metabolites yielded an area under the receiver operating curve > 0.75. Meanwhile, seven abnormal metabolic pathways were correlated with differential metabolites, such as metabolic pathways; neuroactive ligand‒receptor interaction; and glycine, serine, and threonine metabolism. To our knowledge, this is the first study to reveal the characteristic metabolite changes in sera from NT1 patients for the selection of potential blood biomarkers and the elucidation of NT1 pathogenesis.

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.

Narcolepsies, update in 2023

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

Non-invasive detection of narcolepsy type I phenotypical features and disease progression by continuous home-cage monitoring of activity in two mouse models: the HCRT-KO and DTA model

Narcolepsy type 1 (NT1) is a neurological disorder caused by disruption of hypocretin (HCRT; or orexin) neurotransmission leading to fragmented sleep/wake states, excessive daytime sleepiness, and cataplexy (abrupt muscle atonia during wakefulness). Electroencephalography and electromyography (EEG/EMG) monitoring is the gold standard to assess NT1 phenotypical features in both humans and mice. Here, we evaluated the digital ventilated home-cage (DVC®) activity system as an alternative to detect NT1 features in two NT1 mouse models: the genetic HCRT-knockout (-KO) model, and the inducible HCRT neuron-ablation hcrt-tTA;TetO-DTA (DTA) model, including both sexes. NT1 mice exhibited an altered dark phase activity profile and increased state transitions, compared to the wild-type (WT) phenotype. An inability to sustain activity periods >40 min represented a robust activity-based NT1 biomarker. These features were observable within the first weeks of HCRT neuron degeneration in DTA mice. We also created a nest-identification algorithm to differentiate between inactivity and activity, inside and outside the nest as a sleep and wake proxy, respectively, showing significant correlations with EEG/EMG-assessed sleep/wake behavior. Lastly, we tested the sensitivity of the activity system to detect behavioral changes in response to interventions such as repeated saline injection and chocolate. Surprisingly, daily consecutive saline injections significantly reduced activity and increased nest time of HCRT-WT mice. Chocolate increased total activity in all mice, and increased the frequency of short out-of-nest inactivity episodes in HCRT-KO mice. We conclude that the DVC® system provides a useful tool for non-invasive monitoring of NT1 phenotypical features, and has the potential to monitor drug effects in NT1 mice.

Associations between psychiatric comorbid disorders and executive dysfunctions in hypocretin-1 deficient pediatric narcolepsy type1

OBJECTIVE/BACKGROUND

Psychiatric symptoms and cognitive deficits add significantly to impairment in academic achievement and quality of life in patients with narcolepsy. The primary aim of this study was to evaluate the prevalence of psychiatric disorders and executive dysfunctions, secondly to explore the association between psychiatric comorbidity, executive dysfunctions, subjective and objective sleep measures, and severity of cerebrospinal fluid (CSF) hypocretin-1 deficiency in pediatric narcolepsy type 1 (PNT1).

PATIENTS/METHODS

Cross-sectional study of 59 consecutively included PNT1 patients (age: 6-20 years; 34:25 girls: boys; 54/59 H1N1 (Pandemrix®)-vaccinated). Core narcolepsy symptoms including subjective sleepiness, polysomnography and multiple sleep latency test results, CSF hypocretin-1 levels, psychiatric disorders (by semistructured diagnostic interview Kaufmann Schedule for Affective Disorders and Schizophrenia Present and Lifetime version (KSADS)), and executive dysfunction (by Behavior Rating of Executive Function (BRIEF)) were assessed.

RESULTS

52.5% of the patients had one or more psychiatric comorbid disorder, and 64.7% had executive dysfunction in a clinically relevant range, with no sex difference in prevalence, while older age was associated with poorer executive function (p=0.013). Having any psychiatric comorbid disorder was associated with poorer executive functions (p=0.001). CSF hypocretin-1 deficiency severity was significantly associated with presence of psychiatric comorbidity (p=0.022) and poorer executive functions (p=0.030), and poorer executive functions was associated with subjective sleepiness (p=0.009).

CONCLUSIONS

The high occurrence of, and association between, psychiatric comorbidity and executive dysfunction underlines the importance of close attention to both these comorbidities in clinical care of NT1.

Long-Term Treatment of Narcolepsy and Idiopathic Hypersomnia with Low-Sodium Oxybate

Narcolepsy and idiopathic hypersomnia are chronic conditions that negatively affect alertness, mental and physical energy, functioning, and quality of life (QoL). Calcium, magnesium, potassium, and sodium oxybates (low-sodium oxybate; LXB) is an oxybate formulation with 92% less sodium than sodium oxybate (SXB; a treatment for narcolepsy) and the same active moiety. LXB is approved in the US for treatment of cataplexy or excessive daytime sleepiness (EDS) in patients 7 years of age or older with narcolepsy, and idiopathic hypersomnia in adults. In Phase 3 clinical trials, LXB exhibited a safety profile consistent with that of SXB in narcolepsy. Besides continued efficacy in treating symptoms, potential benefits of long-term LXB treatment include flexible optimization of dosing and regimen, improvement of QoL and functioning, weight loss, and (relative to SXB in narcolepsy) health benefits of reduced sodium content. Dosing of LXB is twice nightly (for narcolepsy) or once or twice nightly (for idiopathic hypersomnia) based on patient characteristics and response, and individualized titration can be leveraged over the long term as a patient's life circumstances change. Patients with narcolepsy transitioning from SXB initiate LXB at the same dose, and most patients require no further changes to achieve similar efficacy and tolerability. Improvements in functioning and QoL with LXB treatment could have cascading positive effects in multiple domains, particularly in younger patients. In clinical trials, LXB was associated with weight loss in both narcolepsy (in which obesity is a well-established comorbidity) and idiopathic hypersomnia, only occasionally leading participants to be underweight. As both narcolepsy and idiopathic hypersomnia are associated with increased risk of cardiometabolic and cardiovascular comorbidities, limiting medication-related sodium intake with LXB may have significant health benefits, although this has not yet been verified prospectively due to the prolonged follow-up required. LXB is a promising long-term treatment for narcolepsy and idiopathic hypersomnia.

Clinician Preferences for Oxybate Treatment for Narcolepsy: Survey and Discrete Choice Experiment

INTRODUCTION

Immediate-release sodium oxybate (SXB) has been Food and Drug Administration (FDA)-approved to treat narcolepsy since 2002; in 2020, a mixed-salt oxybates formulation was also approved. Both are taken at bedtime with a second dose taken 2.5-4 h later. A third oxybate option, an investigational extended-release SXB, may soon be available. This study was undertaken to understand clinicians' preferences between these 3 different oxybate treatments.

METHODS

Clinicians in active clinical practice for 3-35 years and experience treating patients with narcolepsy were recruited. A 30-min web-based survey quantified narcolepsy disease-state attitudes, treatment perceptions, and satisfaction with oxybates on 9-point scales. A discrete choice experiment (DCE) of 12 choice sets, with 2 hypothetical treatment profiles in each, was used to capture clinician preferences about overall oxybate therapy preference, impact on patient quality of life (QoL), and patient anxiety/stress. Attributes associated with current therapies and those expected to be available in the near future were included in the design.

RESULTS

The clinicians surveyed (n = 100) indicated that narcolepsy has a negative impact on patient QoL (mean rating, 7.7) and rated impact on QoL and treatment efficacy as the most important aspects of a narcolepsy treatment (mean rating, 7.3-7.7). Clinicians with experience prescribing oxybates had moderately high satisfaction with SXB and mixed-salt oxybates efficacy (mean ratings, 6.5-6.9) and safety (mean ratings, 6.1-6.7) and lower satisfaction with nightly dosing frequency (mean rating, 5.9 and 6.3, respectively). In the DCE, dosing frequency was the most important attribute driving overall product choice, patient QoL, and reducing patient anxiety/stress (relative attribute importance, 46.1, 41.7, and 44.0, respectively), with once nightly preferred over twice nightly.

CONCLUSION

Clinicians indicated a significantly higher preference for the once-at-bedtime dosing schedule versus twice nightly in selecting oxybate therapies overall and when aiming to improve patient QoL or reduce patient anxiety.

The Correlation of Sleep Disturbance and Location of Glioma Tumors: A Narrative Review

Sleep disturbance can occur when sleep centers of the brain, regions that are responsible for coordinating and generating healthy amounts of sleep, are disrupted by glioma growth or surgical resection. Several disorders cause disruptions to the average duration, quality, or patterns of sleep, resulting in sleep disturbance. It is unknown whether specific sleep disorders can be reliably correlated with glioma growth, but there are sufficient numbers of case reports to suggest that a connection is possible. In this manuscript, these case reports and retrospective chart reviews are considered in the context of the current primary literature on sleep disturbance and glioma diagnosis to identify a new and useful connection which warrants further systematic and scientific examination in preclinical animal models. Confirmation of the relationship between disruption of the sleep centers in the brain and glioma location could have significant implications for diagnostics, treatment, monitoring of metastasis/recurrence, and end-of-life considerations.

[Potential teratogenicity of modafinil - Conflicting evidence, need for research]

Central disorders of hypersomnolence include narcolepsy type 1, narcolepsy type 2, idiopathic hypersomnia and hypersomnia associated with medical or mental disorders. Treatment is both non-pharmacological and pharmacological, including wake enhancing drugs and stimulants. One of the first-line treatment (modafinil, MODIODAL®) was the subject of a health authority alert in 2019 concerning a risk of major congenital malformations when taken during organogenesis. Since this date, three epidemiological studies have presented contradictory results. Given their methodological weaknesses, it is not possible at this stage to confirm or deny such a risk for the embryo and its nature if there is one. In clinical practice, because of these uncertainties, it is preferable if possible to suspend the treatment of a pregnant woman during the first 10 weeks from last menstrual period (organogenesis). There is an unmet clinical need for research to clarify the potential teratogenic impact of modafinil.

Sex differences in the effects of sleep disorders on cognitive dysfunction

Sleep is an essential physiological function that sustains human life. Sleep disorders involve problems with the quality, duration, and abnormal behaviour of sleep. Insomnia is the most common sleep disorder, followed by sleep-disordered breathing (SDB). Sleep disorders often occur along with medical conditions or other mental health conditions. Of particular interest to researchers is the role of sleep disorders in cognitive dysfunction. Sleep disorder is a risk factor for cognitive dysfunction, yet the exact pathogenesis is still far from agreement. Little is known about how sex differences influence the changes in cognitive functions caused by sleep disorders. This narrative review examines how sleep disorders might affect cognitive impairment, and then explores the sex-specific consequences of sleep disorders as a risk factor for dementia and the potential underlying mechanisms. Some insights on the direction of further research are also presented.

Genetics and epigenetics of rare hypersomnia

Herein we focus on connections between genetics and some central disorders of hypersomnolence - narcolepsy types 1 and 2 (NT1, NT2), idiopathic hypersomnia (IH), and Kleine-Levin syndrome (KLS) - for a better understanding of their etiopathogenetic mechanisms and a better diagnostic and therapeutic definition. Gene pleiotropism influences neurological and sleep disorders such as hypersomnia; therefore, genetics allows us to uncover common pathways to different pathologies, with potential new therapeutic perspectives. An important body of evidence has accumulated on NT1 and IH, allowing a better understanding of etiopathogenesis, disease biomarkers, and possible new therapeutic approaches. Further studies are needed in the field of epigenetics, which has a potential role in the modulation of biological specific hypersomnia pathways.