Narcolepsy type 1 (NT1) is associated with severe loss of orexin neurons and characterized by symptoms including excessive daytime sleepiness and cataplexy. Current medications indicated for NT1 often show limited efficacy, not addressing the full spectrum of symptoms, demonstrating a need for novel drugs. We discovered a parenteral orexin receptor 2 (OX2R) agonist, danavorexton, and an orally available OX2R agonist, TAK-994; both improving NT1 phenotypes in mouse models and individuals with NT1. However, danavorexton has limited oral availability and TAK-994 has a risk of off-target liver toxicity. To avoid off-target-based adverse events, a highly potent molecule with low effective dose is preferred. Here, we show that a novel OX2R-selective agonist, TAK-861 [N-{(2S,3R)-4,4-Difluoro-1-(2-hydroxy-2-methylpropanoyl)-2-[(2,3\',5\'-trifluoro[1,1\'-biphenyl]-3-yl)methyl]pyrrolidin-3-yl}ethanesulfonamide], activates OX2R with a half-maximal effective concentration of 2.5 nM and promotes wakefulness at 1 mg/kg in mice and monkeys, suggesting ~ tenfold higher potency and lower effective dosage than TAK-994. Similar to TAK-994, TAK-861 substantially ameliorates wakefulness fragmentation and cataplexy-like episodes in orexin/ataxin-3 and orexin-tTA;TetO DTA mice (NT1 mouse models). Compared with modafinil, TAK-861 induces highly correlated brain-wide neuronal activation in orexin-tTA;TetO DTA mice, suggesting efficient wake-promoting effects. Thus, TAK-861 has potential as an effective treatment for individuals with hypersomnia disorders including narcolepsy, potentially with a favorable safety profile.

Narcolepsy type 1 (NT1) is a sleep-wake disorder in which people typically experience excessive daytime sleepiness, cataplexy and other sleep-wake disturbances impairing daily life activities. NT1 symptoms are due to hypocretin deficiency. The cause for the observed hypocretin deficiency remains unclear, even though the most likely hypothesis is that this is due to an auto-immune process. The search for autoantibodies and autoreactive T-cells has not yet produced conclusive evidence for or against the auto-immune hypothesis. Other mechanisms, such as reduced corticotrophin-releasing hormone production in the paraventricular nucleus have recently been suggested. There is no reversive treatment, and the therapeutic approach is symptomatic. Early diagnosis and appropriate NT1 treatment is essential, especially in children to prevent impaired cognitive, emotional and social development. Hypocretin receptor agonists have been designed to replace the attenuated hypocretin signalling. Pre-clinical and clinical trials have shown encouraging initial results. A better understanding of NT1 pathophysiology may contribute to faster diagnosis or treatments, which may cure or prevent it.

BACKGROUND: Narcolepsy is a rare neurological disease caused by dysfunction of hypocretin-producing neurons. Hypocretin concentrations in the cerebrospinal fluid (CSF) of less than 110 pg/ml are considered pathological in adults.
OBJECTIVE: To compare hypocretin levels of children with narcolepsy type 1, type 2 and disease control groups, in addition to a detailed CSF analysis, clinical and polysomnographic parameters.
METHODS: In a retrospective, cross-sectional study, children diagnosed with narcolepsy based on clinical and polysomnographic parameters, who received a CSF analysis and hypocretin measurement, in addition to controls, were included. CSF was analyzed for the presence of cells, total protein, lactate, intrathecal synthesis of antibodies against measles, rubella and/or varicella zoster, and oligoclonal bands. All children had a complete sleep study including a multiple sleep latency test (MSLT).
RESULTS: 49 children with narcolepsy type 1, 15 children with type 2 and 37 children with other (suspected) neurological diseases were included. CSF routine analysis did not reveal any differences between the three groups. All children with narcolepsy type 1 had hypocretin levels of less than 110 pg/ml (range: 10-101 pg/ml). Hypocretin levels in type 2 patients ranged from 43 to 436 pg/ml (median 157 pg/ml). The median hypocretin level in the control cohort was 365 pg/ml (range: 153-583 pg/ml). In 4 children with narcolepsy type 2 the diagnosis was changed to narcolepsy level 1 because of a CSF hypocretin level of less than 110 pg/ml according to the recently proposed criteria, which consider the measurement of hypocretin in CSF.
CONCLUSIONS: Children with narcolepsy type 1 showed significantly lower CSF hypocretin levels than children with narcolepsy type 2 and controls. As suggested by the recently published narcolepsy criteria, hypocretin levels of less than 110 pg/ml should be used as an additional criterion for the presence of narcolepsy type 1 in children.

OBJECTIVE: The purpose of this study was to investigate the effects of neck myoclonus (NM) on sleep quality and daytime sleepiness in patients with narcolepsy (NT) and to further explore possible underlying mechanisms.
METHODS: We included 72 patients with narcolepsy type 1 (NT1), 34 patients with narcolepsy type 2 (NT2) and 33 healthy controls. Patients underwent questionnaires, lumbar puncture procedure, polysomnography, and multiple sleep latency test (MSLT). Healthy controls underwent polysomnography and questionnaires. Orexin-A levels in the cerebrospinal fluid (CSF) were analyzed by radioimmunoassay. Three catecholamines, including dopamine, norepinephrine and epinephrine, in the CSF were measured by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS).
RESULTS: Both the NT1 and NT2 groups displayed a higher level of NM incidence rate and index compared to the control group in PSG. NT1 displayed greater MSLT REM--NM incidence rate and index than NT2. NM were often associated with arousal or awakening and body movements, which had a prominent influence on sleep quality in both narcoleptic patients and controls. There was a positive correlation between the NM index and the Pittsburgh Sleep Quality Index (PSQI), Stanford Sleepiness Scale (SSS) and Ullanlinna Narcolepsy Scale (UNS) scores in NT1 patients. In MSLT of NT1 patients, REM-NM index were positively correlated with the CSF dopamine levels, and there were elevated dopamine levels but reduced orexin-A levels in patients with REM-NM.
CONCLUSIONS: NM incidence rate and index were high in patients with narcolepsy, which had a huge effect on sleep quality and aggravated daytime sleepiness. NM should be considered pathological and viewed as a new sleep-related movement disorder. Orexin-A and dopamine may be involved in the development of NM.

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.

My research has always focused on sleep, whether monitoring neural activity (microwires, c-Fos, calcium imaging), triggering it with optogenetics or pharmacologically (anandamide, cholinergic agonists), or measuring levels of endogenous sleep agents such as adenosine. A recurring theme of my research is to use new tools to find the sweet spot in the brain where the signal to sleep begins. My goal is to identify the circuit, determine whether it degrades with age or disease, and repair the circuit when it fails. I am deeply grateful to my mentors for introducing me to the science of sleep, to my students and colleagues for helping me in my quest, and to the NIH and VA Research for supporting the research. Because of the collective efforts of sleep researchers, the public is more aware of the importance of sleep to a healthy lifestyle.

OBJECTIVE: To collect prodromal symptoms experienced by participants with narcolepsy and idiopathic hypersomnia (considered \"hypersomnolence experts\") prior to drowsy driving and counter-strategies used to maintain alertness.
METHODS: Systematic, face-to-face interview (using a semi-structured questionnaire), including clinical measures, frequency of car accidents/near misses, and symptoms experienced before impending drowsy driving episodes and counter-strategies.
RESULTS: Among 61 participants (32 with narcolepsy, 29 with idiopathic hypersomnia; 56 drivers), 61% of drivers had at least one lifetime accident/near miss. They had a higher sleepiness score (14 ± 4 vs. 11 ± 5, P<0.04) than those without an accident/near miss, but no other differences in demographics, driving experience, medical conditions, symptoms, sleep tests, and treatment. All but three participants experienced prodromal symptoms of drowsy driving, which included postural and motor changes (86.9%: axial hypotonia - e.g., eyelid droop, stereotyped movements), cognitive impairment (53.3%: automatic steering, difficulty concentrating/shifting, dissociation, mind wandering, dreaming), sensory (65%: paresthesia, pain, stiffness, heaviness, blunted perceptions such as a flat dashboard with loss of 3D, illusions and hallucinations), and autonomic symptoms (10%, altered heart/breath rate, penile erection). Counterstrategies included self-stimulation from external sources (pain, cold air, music, drinks, driving with bare feet), motor changes (upright posture, movements), and surprise (sudden braking).
CONCLUSIONS: Drowsy driving symptoms can result from \"local\" NREM, entry in N1 sleep, and hybrid wake/REM sleep states. These rich qualitative insights from participants with narcolepsy and idiopathic hypersomnia, as well as sophisticated counter-strategies, can be gathered to reduce the crash risk in this population, but also in inexperienced healthy drivers.

Sleep is a physiological state that is essential for maintaining physical and mental health. Sleep disorders and sleep deprivation therefore have many adverse effects, including an increased risk of metabolic diseases and a decline in cognitive function that may be implicated in the long-term development of neurodegenerative diseases. There is increasing evidence that microglia, the resident immune cells of the central nervous system (CNS), are involved in regulating the sleep-wake cycle and the CNS response to sleep alteration and deprivation. In this chapter, we will discuss the involvement of microglia in various sleep disorders, including sleep-disordered breathing, insomnia, narcolepsy, myalgic encephalomyelitis/chronic fatigue syndrome, and idiopathic rapid-eye-movement sleep behavior disorder. We will also explore the impact of acute and chronic sleep deprivation on microglial functions. Moreover, we will look into the potential involvement of microglia in sleep disorders as a comorbidity to Alzheimer\'s disease and Parkinson\'s disease.

Narcolepsy is mainly associated with excessive daytime sleepiness, but the characteristic feature is abnormal rapid eye movement (REM) sleep phenomena. REM sleep disturbances can manifest as cataplexy (in narcolepsy type 1), sleep paralysis, sleep-related hallucinations, REM sleep behavior disorder, abnormal dreams, polysomnographic evidence of REM sleep disruption with sleep-onset REM periods, and fragmented REM sleep. Characterization of REM sleep and related symptoms facilitates the differentiation of narcolepsy from other central hypersomnolence disorders and aids in distinguishing between narcolepsy types 1 and 2. A circuit comprising regions within the brainstem, forebrain, and hypothalamus is involved in generating and regulating REM sleep, which is influenced by changes in monoamines, acetylcholine, and neuropeptides. REM sleep is associated with brainstem functions, including autonomic control, and REM sleep disturbances may be associated with increased cardiovascular risk. Medications used to treat narcolepsy (and REM-related symptoms of narcolepsy) include stimulants/wake-promoting agents, pitolisant, oxybates, and antidepressants; hypocretin agonists are a potential new class of therapeutics. The role of REM sleep disturbances in narcolepsy remains an area of active research in pathophysiology, symptom management, and treatment. This review summarizes the current understanding of the role of REM sleep and its dysfunction in narcolepsy.

BACKGROUND: The study seeks to assess serum neurofilament light chain (NfL) levels in paediatric narcolepsy-diagnosed patients. Moreover, it aims to explore the correlation between NfL levels and the severity of narcolepsy symptoms, sleep quality, and manifestations of anxiety and depression.
METHODS: This retrospective analysis included 98 paediatric narcolepsy cases and 100 controls matched for age and gender. The study focused on comparing serum NfL levels across these groups. Severity of EDS in patients was measured with the Epworth Sleepiness Scale (ESS). Moreover, the Pittsburgh Sleep Quality Index (PSQI), Hamilton Depression Rating Scale-24 (HAMD-24), and Hamilton Anxiety Scale-14 (HAMA-14) were used to assess narcolepsy symptoms, sleep quality, and psychological conditions.
RESULTS: Patients with paediatric narcolepsy had significantly higher serum NfL levels than controls (P < 0.05). Additionally, a positive correlation was found between serum NfL levels and ESS scores (P < 0.001). An independent link between serum NfL and paediatric narcolepsy was established via multiple logistic regression (OR = 0.943, 95 % CI = 0.921-0.993, P = 0.004). Moreover, serum NfL\'s diagnostic precision for paediatric narcolepsy was evident from the ROC curve area of 0.938 (95 % CI: 0.86-0.99, P < 0.001).
CONCLUSIONS: The study implies a positive correlation between increased serum NfL levels and the severity of paediatric narcolepsy. Nevertheless, the causative link between serum NfL levels and paediatric narcolepsy remains uncertain, highlighting the need for larger sample sizes and well-structured cohort studies to offer more definitive.