Vagus nerve stimulation for the treatment of narcolepsy

BACKGROUND AND OBJECTIVE

No study on neurostimulation in narcolepsy is available until now. Arousal- and wake-promoting effects of vagus nerve stimulation (VNS) have been demonstrated in animal experiments and are well-known as side effects of VNS therapy in epilepsy and depression. The objective was to evaluate the therapeutic effect of VNS on daily sleepiness and cataplexies in narcolepsy.

METHODS

In our open-label prospective comparative study, we included narcolepsy patients who were treated with VNS because of depression or epilepsy and compared them to controls without narcolepsy treated with VNS for depression or epilepsy (18 patients in each group, aged 31.5 ± 8.2 years). We evaluated daily sleepiness (Epworth Sleepiness Scale, ESS) and the number of cataplexies per week before the implantation of VNS and at three and six month follow-ups.

RESULTS

Compared to baseline (ESS: 15.9 ± 2.5) patients with narcolepsy showed a significant improvement on ESS after three months (11.2 ± 3.3, p < 0.05) and six months (9.6 ± 2.8, p < 0.001) and a trend to reduction of cataplexies. No significant ESS-improvement was observed in patients without narcolepsy (14.9 ± 3.9, 13.6 ± 3.7, 13.2 ± 3.5, p = 0.2 at baseline, three and six months, correspondingly). Side effects did not differ between the study groups.

CONCLUSION

In this first evaluation of VNS in narcolepsy, we found a significant improvement of daily sleepiness due to this type of neurostimulation. VNS could be a promising non-medical treatment in narcolepsy.

Clinical Evaluation and Management of Narcolepsy in Children and Adolescents

While sleepiness is common among children, and particularly adolescents, profound sleepiness in the setting of apparently adequate sleep should prompt consideration of a central disorder of hypersomnolence. These disorders, which include narcolepsy, idiopathic hypersomnia, Kleine-Levin syndrome, and others, are likely underrecognized in the pediatric population. Narcolepsy in particular should be of interest to child neurologists as the unique signs and symptoms of this disease often prompt evaluation in pediatric neurology clinics. While sleepiness may appear to be a straightforward complaint, its evaluation requires a nuanced approach. Cataplexy, a hallmark of narcolepsy, can be confused for other neurologic conditions, though understanding its various manifestations makes it readily identifiable. Clinicians should be aware of these symptoms, as delay in diagnosis and misdiagnosis are common in childhood narcolepsy. While treatment options have been limited in the past, many new therapeutic options have become available and can result in significant improvement in symptoms. Given the age at presentation, paroxysmal and chronic features, diagnostic modalities, and available treatment options, the field of child neurology is well equipped to see patients with narcolepsy. In this review, I will focus on the presentation, evaluation, and management of pediatric patients with narcolepsy.

Idiopathic Hypersomnia and Kleine-Levin Syndrome: Primary Disorders of Hypersomnolence Beyond Narcolepsy

Daytime sleepiness is common amongst children and adolescents. Inadequate sleep duration, inappropriate school start times, and the delay in sleep phase of adolescence may all contribute. Nocturnal sleep disruption due to sleep disorders such as obstructive sleep apnea or restless legs syndrome/periodic limb movement disorder may also lead to daytime sleepiness. Profound sleepiness however, when occurring in the setting of adequate sleep duration, is rare amongst children and adolescents and may prompt consideration of a central disorder of hypersomnolence (CDH). Narcolepsy is the archetypal and most studied form of CDH and a detailed review of the presentation, evaluation, treatment of narcolepsy is included separately in this edition of Seminars in Pediatric Neurology. In addition to narcolepsy, 2 other forms of primary CDH exist, idiopathic hypersomnia (IH) and Kleine-Levin syndrome (KLS). Onset of IH and KLS occurs most frequently during the pediatric age range and presentation may include signs of encephalopathy in addition to hypersomnolence. As such, they are of particular relevance to pediatric neurology and associated fields. Unfortunately, when compared to narcolepsy little is known about IH and KLS, at both the physiologic and clinical level. This review will focus on the presentation, evaluation, and management of idiopathic hypersomnia and Kleine-Levin syndrome in the pediatric population.

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.

Sleep Disorders in Childhood

OBJECTIVE

This article provides a comprehensive review of pediatric sleep disorders including the clinical features, diagnosis, and treatment of sleep-disordered breathing, insomnia, parasomnias, restless sleep disorder, restless legs syndrome, narcolepsy in childhood, and Kleine-Levin syndrome.

LATEST DEVELOPMENTS

Our understanding of pediatric sleep pathophysiology continues to evolve, and diagnostic and treatment modalities have expanded. A low-sodium oxybate formulation was approved in July 2020 in the United States to treat cataplexy and excessive daytime sleepiness in patients 7 years old and older with narcolepsy. A validated pediatric hypersomnolence survey for pediatric narcolepsy and idiopathic hypersomnia with high sensitivity, specificity, and interrater reliability is now available.

ESSENTIAL POINTS

The clinical presentation, diagnostics, and treatment of children with sleep disorders differ from those of adults. Untreated sleep disorders in childhood can lead to adverse physical and psychological consequences in adults. Correctly diagnosing and treating sleep disorders in youth can prevent a significant burden of disease in adulthood.

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

BACKGROUND AND OBJECTIVE

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

METHODS

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

RESULT

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

CONCLUSION

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

Pediatric sleep: current knowledge, gaps, and opportunities for the future

This White Paper addresses the current gaps in knowledge, as well as opportunities for future studies in pediatric sleep. The Sleep Research Society's Pipeline Development Committee assembled a panel of experts tasked to provide information to those interested in learning more about the field of pediatric sleep, including trainees. We cover the scope of pediatric sleep, including epidemiological studies and the development of sleep and circadian rhythms in early childhood and adolescence. Additionally, we discuss current knowledge of insufficient sleep and circadian disruption, addressing the neuropsychological impact (affective functioning) and cardiometabolic consequences. A significant portion of this White Paper explores pediatric sleep disorders (including circadian rhythm disorders, insomnia, restless leg and periodic limb movement disorder, narcolepsy, and sleep apnea), as well as sleep and neurodevelopment disorders (e.g. autism and attention deficit hyperactivity disorder). Finally, we end with a discussion on sleep and public health policy. Although we have made strides in our knowledge of pediatric sleep, it is imperative that we address the gaps to the best of our knowledge and the pitfalls of our methodologies. For example, more work needs to be done to assess pediatric sleep using objective methodologies (i.e. actigraphy and polysomnography), to explore sleep disparities, to improve accessibility to evidence-based treatments, and to identify potential risks and protective markers of disorders in children. Expanding trainee exposure to pediatric sleep and elucidating future directions for study will significantly improve the future of the field.

School Problems and School Support for Children with Narcolepsy: Parent, Teacher, and Child Reports

OBJECTIVE

To assess problems faced by children with type 1 narcolepsy (NT1) at school and obtain insight into potential interventions for these problems.

METHODS

We recruited children and adolescents with NT1 from three Dutch sleep-wake centers. Children, parents, and teachers completed questionnaires about school functioning, interventions in the classroom, global functioning (DISABKIDS), and depressive symptoms (CDI).

RESULTS

Eighteen children (7-12 years) and thirty-seven adolescents (13-19 years) with NT1 were recruited. Teachers' most frequently reported school problems were concentration problems and fatigue (reported by about 60% in both children and adolescents). The most common arrangements at school were, for children, discussing school excursions (68%) and taking a nap at school (50%) and, for adolescents, a place to nap at school (75%) and discussing school excursions (71%). Regular naps at home on the weekend (children 71% and adolescents 73%) were more common than regular naps at school (children 24% and adolescents 59%). Only a minority of individuals used other interventions. School support by specialized school workers was associated with significantly more classroom interventions (3.5 versus 1.0 in children and 5.2 versus 4.1 in adolescents) and napping at school, but not with better global functioning, lower depressive symptom levels, or napping during the weekends.

CONCLUSIONS

Children with NT1 have various problems at school, even after medical treatment. Interventions to help children with NT1 within the classroom do not seem to be fully implemented. School support was associated with the higher implementation of these interventions. Longitudinal studies are warranted to examine how interventions can be better implemented within the school.

TCM syndrome differentiation and treatment of narcolepsy based on neurobiological mechanism: A review

Narcolepsy is a relatively rare brain disorder caused by the selective loss of orexin neurons. Narcolepsy is divided into Narcolepsy Type 1 (NT1) and Narcolepsis Type 2 (NT2). The pathogenesis of NT1 has been well established due to the severe loss of orexin neurons, while NT2 is still poorly understood, and little is known about its underlying neurobiological mechanisms. human leukocyte antigen alleles have been found to strongly influence the development of narcolepsy, with more than 90% of NT1 patients carrying the human leukocyte antigen II allele DQB1*06:02. In addition to the genetic evidence for the DQBI*06:02 allele, some other evidence suggests that a T cell-mediated immune mechanism destroys the orexin neurons of NT1, with CD4 + T cells being key. For this disease, traditional Chinese medicine (TCM) therapy has its own characteristics and advantages, especially the combination of acupuncture and medicine in the treatment of this disease in TCM, which has made considerable and gratifying progress. The purpose of this review is to introduce the frontier progress of neurobiology of narcolepsy, and to explore the syndrome differentiation and treatment of narcolepsy with the combined use of TCM and Western medicine combined with TCM.

Development and Validation of the Pediatric Hypersomnolence Survey

BACKGROUND AND OBJECTIVES

Narcolepsy and idiopathic hypersomnia usually begin in early adolescence, but diagnostic delays ranging from 5 to 10 years are common, affecting disease burden. To improve early identification of these treatable conditions, we developed and validated the Pediatric Hypersomnolence Survey (PHS).

METHODS

Content was developed through literature review, patient focus groups, interviews with experts in the field, and field testing. We then validated the 14-item self-reported survey across 3 hospitals and web recruitment from patient groups. In the validation phase, we recruited a total of 331 participants (patients with narcolepsy type 1 [n = 64], narcolepsy type 2 [n = 34], idiopathic hypersomnia [n = 36], and other sleep disorders [n = 97] and healthy controls [n = 100], ages 8-18 years) to complete the survey. We assessed a range of psychometric properties, including discriminant diagnostic validity for CNS disorders of hypersomnolence using receiver operating characteristic curve analysis and reliability across a 1-week period.

RESULTS

Confirmatory factor analysis indicated a 4-domain solution with good reliability expressed by satisfactory omega values. Across groups, the PHS total score showed appropriate positive correlations with other validated surveys of sleepiness (r = 0.65-0.78, p < 0.001) and negative correlations with multiple sleep latency test measures (mean sleep latency: r = -0.27, p = 0.006; number of sleep-onset REM periods: r = 0.26, p = 0.007). Compared to controls and patients with other sleep disorders, the area under the curve for participants with narcolepsy or idiopathic hypersomnia was 0.87 (standard error 0.02, 95% CI 0.83-0.91) with high sensitivity (81.3, 95% CI 73.7%-87.5%) and specificity (81.2%, 95 CI 75.1%-86.4%). Test-retest reliability was r = 0.87.

DISCUSSION

The PHS is a valid and reliable tool for clinicians to identify pediatric patients with narcolepsy and idiopathic hypersomnia. Implemented in clinical practice, the PHS will potentially decrease diagnostic delays and time to treatment, ultimately reducing disease burden for these debilitating conditions.

CLASSIFICATION OF EVIDENCE

This study provides Class III evidence that the PHS accurately identifies patients with central disorders of hypersomnolence.

Common Sleep Disorders in Adults: Diagnosis and Management

Sleep disorders are common in the general adult population and are associated with adverse effects such as motor vehicle collisions, decreased quality of life, and increased mortality. Patients with sleep disorders can be categorized into three groups: people with problems falling asleep, people with behavior and movement disturbances during sleep, and people with excessive daytime sleepiness. Insomnia, the most common sleep disorder, is defined by difficulty initiating sleep, maintaining sleep, or both, resulting in daytime consequences. Insomnia is diagnosed by history and is treated with cognitive behavior therapy, with or without medications. Rapid eye movement sleep behavior disorder is characterized by increased muscle tone during rapid eye movement sleep, resulting in patients acting out their dreams with potentially harmful effects. Rapid eye movement sleep behavior disorder is diagnosed by polysomnography and treated with melatonin or clonazepam. Restless legs syndrome is defined by an urge to move the legs that worsens when at rest. Restless legs syndrome is treated with gabapentin or dopamine agonists, depending on the severity. Narcolepsy is characterized by excessive daytime sleepiness, cataplexy, sleep paralysis, and sleep hallucinations. Diagnosis is suggested by the history and can be confirmed with polysomnography and a multiple sleep latency test the following day. Narcolepsy is treated with behavior modifications and medications such as stimulants, selective serotonin reuptake inhibitors, sodium oxybate, and pitolisant. Obstructive sleep apnea may be diagnosed in patients with excessive snoring and witnessed apneas and can be diagnosed using overnight polysomnography. Treatment consists of positive airway pressure therapy while sleeping in conjunction with weight loss.

Narcolepsy: A clinical review

ABSTRACT

Narcolepsy continues to be a significantly underdiagnosed/misdiagnosed condition worldwide. According to the National Institutes of Health (NIH), an estimated 135,000 to 200,000 patients in the United States are living with narcolepsy. However, due to the number of patients who either do not seek medical advice for their symptoms or receive an incorrect initial diagnosis at onset, this number may be higher. This article reviews the different subtypes of narcolepsy along with the pathophysiology, screening guidelines, clinical features, diagnosis, and management of the disorder. Educational awareness from a healthcare and patient standpoint can enhance early detection and accurate diagnosis of narcolepsy and improve patient quality of life.

A practical guide to the pharmacological and behavioral therapy of Narcolepsy

Narcolepsy is a rare, chronic, and disabling central nervous system hypersomnia; two forms can be recognized: narcolepsy type 1 (NT1) and narcolepsy type 2 (NT2). Its etiology is still largely unknown, but studies have reported a strong association between NT1 and HLA, as well as a pathogenic association with the deficiency of cerebrospinal hypocretin-1. Thus, the most reliable pathogenic hypothesis is an autoimmune process destroying hypothalamic hypocretin-producing cells. A definitive cure for narcolepsy is not available to date, and although the research in the field is highly promising, up to now, current treatments have aimed to reduce the symptoms by means of different pharmacological approaches. Moreover, overall narcolepsy symptoms management can also benefit from non-pharmacological approaches such as cognitive behavioral therapies (CBTs) and psychosocial interventions to improve the patients' quality of life in both adult and pediatric-affected individuals as well as the well-being of their families. In this review, we summarize the available therapeutic options for narcolepsy, including the pharmacological, behavioral, and psychosocial interventions.

Protocols of a diagnostic study and a randomized controlled non-inferiority trial comparing televisits vs standard in-person outpatient visits for narcolepsy diagnosis and care: TElemedicine for NARcolepsy (TENAR)

BACKGROUND

Narcolepsy is a rare chronic sleep disorder that typically begins in youth. Excessive daytime sleepiness is the main disabling symptom, but the disease is often associated with severe endocrine-metabolic and psychosocial issues, worsened by a long diagnostic delay, requiring a multidisciplinary approach. The scarcity of reference Sleep Centres forces the patient and family to travel for seeking medical consultations, increasing the economic and psychosocial burden of the disease. Growing evidence suggests that Telemedicine may facilitate patient access to sleep consultations and its non-inferiority in terms of patient satisfaction, adherence to treatment, and symptom improvement for sleep disorders. However, Telemedicine clinical and economic benefits for patients with narcolepsy are still unknown.

METHODS

TENAR is a two-part project, including: 1. a cross-sectional study (involving 250 children and adults with suspected narcolepsy) evaluating the accuracy of Teletriage (i.e., a synchronous live interactive sleep assessment through a Televisit) for narcolepsy diagnosis compared to the reference standard; and 2. a two-arm, parallel, open randomized controlled trial (RCT) to demonstrate the non-inferiority of the multidisciplinary care of narcolepsy through Televisits versus standard care. In this RCT, 202 adolescents (> 14 y.o.) and adults with narcolepsy will be randomly allocated (1:1 ratio) either to Televisits via videoconference or to standard in-person outpatient follow-up visits (control arm). The primary outcome is sleepiness control (according to the Epworth Sleepiness Scale). Secondary outcomes are other symptoms control, compliance with treatment, metabolic control, quality of life, feasibility, patient and family satisfaction with care, safety, and disease-related costs. At baseline and at 12 months, patients will undergo neurologic, metabolic, and psychosocial assessments and we will measure primary and secondary outcomes. Primary outcomes will be also measured at 6 months (remotely or in person, according to the arm).

DISCUSSION

TENAR project will assess, for the first time, the feasibility, accuracy, efficacy and safety of Telemedicine procedures applied to the diagnosis and the multidisciplinary care of children and adults with narcolepsy. The study may be a model for the remote management of other rare disorders, offering care access for patients living in areas lacking medical centres with specific expertise.

TRIAL REGISTRATION

Number of the Tele-multidisciplinary care study NCT04316286. Registered 20 March 2020.

Narcolepsy treatment: pharmacological and behavioral strategies in adults and children

Narcolepsy is a disabling, rare, and chronic sleep disorder, currently classified as distinct central nervous system hypersomnia in narcolepsy type 1 (NT1) and narcolepsy type 2 (NT2). Although today a reliable pathogenic hypothesis identifies the cause of NT1 as an autoimmune process destroying hypocretin-producing cells, there is no cure for narcolepsy, and the symptomatic pharmacological available treatments are not entirely effective for all symptoms. Behavioral therapies play a synergistic role in the disease treatment. We here review the available therapeutic options for narcolepsy, including symptomatic pharmacological treatments as well as behavioral and psychosocial interventions that could help clinicians improve the quality of life of patients with narcolepsy in adulthood and childhood.

Drugs Used in Narcolepsy and Other Hypersomnias

Narcolepsy and idiopathic hypersomnia cannot be cured; all available treatments are symptomatic. It is of paramount importance for patients, and their relatives, to be informed about the consequences of these chronic diseases and to become ready to accept the consequences of the diagnosis before starting any treatment. This facilitates the implementation of behavioral modifications and the proper use of medication to decrease the disease burden. A supportive social environment (eg, family members, friends, employer, colleagues, and patient support groups) is instrumental. Current treatment options are discussed with a focus on pharmacologic treatment, including future directions.

Diagnostic Approach and Investigation in Sleep Medicine

PURPOSE OF REVIEW

This article provides a clinical approach to the appropriate investigation and diagnosis of sleep disorders commonly seen by neurologists.

RECENT FINDINGS

Home sleep apnea testing in appropriate situations can replace laboratory polysomnography in many cases of uncomplicated sleep apnea. Multiple sleep latency tests must be performed meticulously and interpreted in the clinical setting to avoid overdiagnoses of narcolepsy. Human leukocyte antigen testing has limited utility in establishing a diagnosis of narcolepsy because a positive test has low specificity. Rapid eye movement (REM) sleep behavior disorder is frequently the first manifestation of an evolving synucleinopathy, and a careful history and neurologic examination are needed to determine other early features of these disorders.

SUMMARY

A meticulous history from the patient, supplemented by collateral history from an observer, is essential to establishing the diagnosis of sleep disorders. Judicious supplementary use of investigations, such as laboratory polysomnography, home sleep apnea testing, wrist actigraphy, and multiple sleep latency tests, can confirm the correct diagnosis. This article describes an approach to the sleepy patient, the patient with neuromuscular disease and possible sleep-disordered breathing, the patient with restless legs syndrome, and young and older patients with abnormal movements during sleep.

Narcolepsy and Other Central Hypersomnias

PURPOSE OF REVIEW

This article focuses on the clinical presentation, pathophysiology, diagnosis, differential diagnosis, and management of narcolepsy type 1 and narcolepsy type 2, idiopathic hypersomnia, Kleine-Levin syndrome, and other central disorders of hypersomnolence, as defined in the International Classification of Sleep Disorders, Third Edition (ICSD-3).

RECENT FINDINGS

In ICSD-3, the names of some central disorders of hypersomnolence have been changed: narcolepsy with cataplexy and narcolepsy without cataplexy have been renamed narcolepsy type 1 and narcolepsy type 2, respectively. A low level of hypocretin-1/orexin-A in the CSF is now theoretically sufficient to diagnose narcolepsy type 1, as it is a highly specific and sensitive biomarker. Conversely, other central hypersomnias are less well-defined disorders with variability in the phenotype, and few reliable biomarkers have been discovered so far. The epidemiologic observation that influenza A (H1N1) infection and vaccination are potential triggering factors of narcolepsy type 1 (discovered during the 2009 H1N1 pandemic) has increased interest in this rare disease, and progress is being made to better understand the process (highly suspected to be autoimmune) responsible for the destruction of hypocretin neurons. Treatment of narcolepsy remains largely symptomatic, usually initially with modafinil or armodafinil or with higher-potency stimulants such as methylphenidate or amphetamines. Several newer wake-promoting agents and psychostimulants have also been developed, including sodium oxybate, which has a role in the treatment of cataplexy and as an adjunctive wake-promoting agent, and pitolisant, a selective histamine H3 receptor inverse agonist that is currently only available in Europe.

SUMMARY

Although far less common than many other sleep disorders, central hypersomnias are among the most severe and disabling diseases in the field of sleep medicine, and their early recognition is of major importance for patients, especially children, to maximize their quality of life and functioning in activities of daily living.

Effective treatment of narcolepsy-like symptoms with high-frequency repetitive transcranial magnetic stimulation: A case report

RATIONALE

Narcolepsy is a rare sleep disorder with disrupted sleep-architecture. Clinical management of narcolepsy lies dominantly on symptom-driven pharmacotherapy. The treatment role of repetitive transcranial magnetic stimulation (rTMS) for narcolepsy remains unexplored.

PATIENT CONCERNS

In this paper, we present a case of a 14-year-old young girl with excessive daytime sleepiness (EDS), cataplexy and hypnagogic hallucinations.

DIAGNOSES

After excluding other possible medical conditions, this patient was primarily diagnosed with narcolepsy.

INTERVENTIONS

The patient received 25 sessions of high-frequency rTMS over the left dorsolateral prefrontal cortex (DLPFC).

OUTCOMES

The symptoms of EDS and cataplexy significantly improved after rTMS treatment. Meanwhile, her score in the Epworth sleep scale (ESS) also remarkably decreased.

LESSONS

This case indicates that rTMS may be selected as a safe and effective alternative strategy for treating narcolepsy-like symptoms. Well-designed researches are warranted in future investigations on this topic.

Driving Safety and Fitness to Drive in Sleep Disorders

Driving an automobile while sleepy increases the risk of crash-related injury and death. Neurologists see patients with sleepiness due to obstructive sleep apnea, narcolepsy, and a wide variety of neurologic disorders. When addressing fitness to drive, the physician must weigh patient and societal health risks and regional legal mandates. The Driver Fitness Medical Guidelines published by the National Highway Traffic Safety Administration (NHTSA) and the American Association of Motor Vehicle Administrators (AAMVA) provide assistance to clinicians. Drivers with obstructive sleep apnea may continue to drive if they have no excessive daytime sleepiness and their apnea-hypopnea index is less than 20 per hour. Those with excessive daytime sleepiness or an apnea-hypopnea index of 20 per hour or more may not drive until their condition is effectively treated. Drivers with sleep disorders amenable to pharmaceutical treatment (eg, narcolepsy) may resume driving as long as the therapy has eliminated excessive daytime sleepiness. Following these guidelines, documenting compliance to recommended therapy, and using the Epworth Sleepiness Scale to assess subjective sleepiness can be helpful in determining patients' fitness to drive.

[Narcolepsy in childhood and adolescence: symptoms, diagnosis, and therapy. A case report]

Narcolepsy is a rare, multifactorial disease of the hypothalamus characterized by its leading symptoms of excessive daytime sleepiness and cataplexy. Sleep-EEG and a HLA-DR-genotype serve to secure the diagnosis. We report here on a 14-year-old girl suffering from anxieties, depression, school refusal, social withdrawal as well as very frequent attacks of sleep during the day and cataplexy. Currently, there is no approved drug for children and adolescents suffering from narcolepsy. Our patient benefited significantly and quickly from an off-label treatment with methylphenidate in combination with psychoeducation, cognitive behavioral therapy, and family therapy. Narcolepsy is a very rare but probably underestimated differential diagnosis applied to unclear daytime sleepiness, anxieties, or depression in childhood and adolescence. Both the key symptoms and the comorbid symptoms improve significantly under treatment with stimulants, albeit at a higher dosage.

[MANAGEMENT OF CENTRAL HYPERSOMNIAS]

Central hypersomnias include narcolepsy type 1, type 2 and idiopathic hypersomnia with daytime sleepiness excessive in the foreground of the clinical symptoms. Despite major advances in our understanding of the mechanisms of the narcolepsy type 1 with a low level of hypocretin-1 in cerebrospinal fluid, its current management is only symptomatic. The current management is also only symptomatic for type 2 narcolepsy and idiopathic hypersomnia with an unknown pathophysiology. Treatment options may vary from a single drug targeting several symptoms or several drugs treating a specific symptom. The treatment of daytime sleepiness is based on modafinil in first intention. Other psychostimulants such as methylphenidate, pitolisant and exceptionally dextro-amfetamine may be considered. In narcolepsy type 1, antidepressants such as inhibitors of the reuptake of serotonin and noradrenaline will be considered to improve cataplexy. Sodium oxybate is an effective treatment on sleepiness, cataplexy and bad night sleep in narcolepsy. The management for other symptoms or comorbidities should be considered it necessary such as hallucinations, sleep paralysis, the disturbed nighttime sleep, unpleasant dreams, parasomnias, depressive symptoms, overweight/obesity, cardiovascular disease and obstructive sleep apnea syndrome. Important therapeutic perspectives are to be expected concerning new psychostimulant and anticataplectiques, but mainly on immune-based therapies administered as early as possible after disease onset and on hypocretin replacement therapy for patients with severe symptoms.

Narcolepsy: a clinical review

Despite the classic tetrad of clinical features that typify it, narcolepsy remains much under-diagnosed, in part, because of the wide spectrum of clinical phenotypes, but also because of its insidious onset, usually in a young person. The median time to diagnosis from first symptoms remains very long, around 10 years in the UK. Conversely, in the specialist setting, it is likely over-diagnosed, largely because of failure to exclude other causes of hypersomnia. There is an over-reliance on a biological marker of the condition, the multiple sleep latency test (MSLT), which, like many tests, has a significant false-positive and false-negative rate. This review aims to discuss some of the difficulties in achieving a diagnosis, interpretation of investigations, differential diagnosis, and appropriate management of patients with narcolepsy.

Effects of hypocretin/orexin cell transplantation on narcoleptic-like sleep behavior in rats

The sleep disorder narcolepsy is now considered a neurodegenerative disease because there is a massive loss of neurons containing the neuropeptide hypocretin/orexin (HCRT). In consequence, narcoleptic patients have very low cerebrospinal fluid (CSF) levels of HCRT. Studies in animal models of narcolepsy have shown the neurophysiological role of the HCRT system in the development of this disease. For example, the injection of the neurotoxin named hypocretin-2-saporin (HCRT2/SAP) into the lateral hypothalamus (LH) destroys the HCRT neurons, therefore diminishes the contents of HCRT in the CSF and induces narcoleptic-like behavior in rats. Transplants of various cell types have been used to induce recovery in a variety of neurodegenerative animal models. In models such as Parkinson's disease, cell survival has been shown to be small but satisfactory. Similarly, cell transplantation could be employed to implant grafts of HCRT cells into the LH or even other brain regions to treat narcolepsy. Here, we report for the first time that transplantation of HCRT neurons into the LH of HCRT2/SAP-lesioned rats diminishes narcoleptic-like sleep behavior. Therefore, cell transplantation may provide an effective method to treat narcolepsy.

[Narcolepsy-cataplexy today]

Diagnostic criteria and pathophysiology of narcolepsy-cataplexy have evolved considerably over the last 10 years. The main cause, already mentioned in a previous paper, in the Revue Médicale de Liège (65), in 2002, is based, in human beings, on a destruction of specific cells located in the lateral and posterior part of the hypothalamus (the perifornical nuclei, containing some 70,000 neurons), producing peptides which stimulate the central nervous system; they are called hypocretins or orexins. The role of autoimmunity in their disappearance becomes more evident. The treatment is simplified, but remains symptomatic. It is mainly based on Sodium Oxybate or Gamma-Hydroxybutyrate, syrup, prescribed for the night. The authors report on their own experience in this regard and on future therapeutics more targeted towards the cause of the disease.

Sleep problems in children

Sleep complaints and sleep disorders are common during childhood and adolescence. The impact of not getting enough sleep may affect children's' physical health as well emotional, cognitive and social development. Insomnia, sleep-disordered breathing, parasomnias and sleep disturbances associated with medical and psychiatric disorders are some of the commonly encountered sleep disorders in this age group. Changes in sleep architecture and the amount of sleep requirement associated with each stage of development should be considered during an evaluation of sleep disorders in children. Behavioral treatments should be used initially wherever possible especially considering that most pharmacologic agents used to treat pediatric sleep disorders are off-label. In this review we address the most common sleep problems in children/adolescents as they relate to prevalence, presentation and symptoms, evaluation and management.

Management of common sleep disorders

Sleep disorders are common and affect sleep quality and quantity, leading to increased morbidity. Patients with sleep disorders can be categorized as those who cannot sleep, those who will not sleep, those with excessive daytime sleepiness, and those with increased movements during sleep. Insomnia, defined as difficulty initiating or maintaining sleep that results in daytime impairment, is diagnosed using history findings and treated with cognitive behavior therapy, with or without sleep hypnotics. Restless legs syndrome is characterized by an urge to move the legs that worsens with rest, is relieved by movement, and often occurs in the evening or at night. Restless legs syndrome is treated based on the frequency of symptoms. Narcolepsy is characterized by excessive sleepiness, cataplexy, hypnagogic or hypnopompic hallucinations, and sleep paralysis. It is diagnosed using a sleep log or actigraphy, followed by overnight polysomnography and a multiple sleep latency test. Narcolepsy is treated with stimulants, such as modafinil; selective serotonin reuptake inhibitors; or gamma hydroxybutyric acid (sodium oxybate). Patients with snoring and witnessed apneas may have obstructive sleep apnea, which is diagnosed using overnight polysomnography. Continuous positive airway pressure is the most common and effective treatment for obstructive sleep apnea. Rapid eye movement sleep behavior disorder is characterized by increased muscle tone during rapid eye movement sleep, resulting in the patient acting out dreams with possible harmful consequences. It is diagnosed based on history and polysomnography findings, and treated with environmental safety measures and melatonin or clonazepam.

Orexin gene therapy restores the timing and maintenance of wakefulness in narcoleptic mice

STUDY OBJECTIVES

Narcolepsy is caused by selective loss of the orexin/hypocretin-producing neurons of the hypothalamus. For patients with narcolepsy, chronic sleepiness is often the most disabling symptom, but current therapies rarely normalize alertness and do not address the underlying orexin deficiency. We hypothesized that the sleepiness of narcolepsy would substantially improve if orexin signaling were restored in specific brain regions at appropriate times of day.

DESIGN

We used gene therapy to restore orexin signaling in a mouse model of narcolepsy. In these Atx mice, expression of a toxic protein (ataxin-3) selectively kills the orexin neurons.

INTERVENTIONS

To induce ectopic expression of the orexin neuropeptides, we microinjected an adeno-associated viral vector coding for prepro-orexin plus a red fluorescence protein (AAV-orexin) into the mediobasal hypothalamus of Atx and wild-type mice. Control mice received an AAV coding only for red fluorescence protein. Two weeks later, we recorded sleep/wake behavior, locomotor activity, and body temperature and examined the patterns of orexin expression.

MEASUREMENTS AND RESULTS

Atx mice rescued with AAV-orexin produced long bouts of wakefulness and had a normal diurnal pattern of arousal, with the longest bouts of wake and the highest amounts of locomotor activity in the first hours of the night. In addition, AAV-orexin improved the timing of rapid eye movement sleep and the consolidation of nonrapid eye movement sleep in Atx mice.

CONCLUSIONS

These substantial improvements in sleepiness and other symptoms of narcolepsy demonstrate the effectiveness of orexin gene therapy in a mouse model of narcolepsy. Additional work is needed to optimize this approach, but in time, AAV-orexin could become a useful therapeutic option for patients with narcolepsy.

Narcolepsy: clinical approach to etiology, diagnosis, and treatment

Narcolepsy is a neurologic disorder characterized by excessive daytime sleepiness and manifestations of disrupted rapid eye movement sleep stage. The pathologic hallmark is loss of hypocretin neurons in the hypothalamus likely triggered by environmental factors in a susceptible individual. Patients with narcolepsy, in addition to excessive daytime sleepiness, can present with cataplexy, sleep paralysis, sleep fragmentation, and hypnagogic/hypnopompic hallucinations. Approximately 60% to 90% of patients with narcolepsy have cataplexy, characterized by sudden loss of muscle tone. Only 15% of patients manifest all of these symptoms together. Narcolepsy can be misdiagnosed as a psychiatric disorder or even epilepsy. An appropriate clinical history, polysomnogram, Multiple Sleep Latency Test, and, at times, cerebrospinal fluid hypocretin levels are necessary for diagnosis. The treatment of narcolepsy is aimed toward the different symptoms that the patient manifests. Excessive daytime sleepiness is treated with amphetamine-like or non-amphetamine-like stimulants. Cataplexy is treated with sodium oxybate, tricyclic antidepressants, or selective serotonin and norepinephrine reuptake inhibitors. Sleep paralysis, hallucinations, and fragmented sleep may be treated with benzodiazepine hypnotics or sodium oxybate. Patients with narcolepsy should avoid sleep deprivation, sleep at regular hours, and, if possible, schedule routine napping.

[Brazilian guidelines for the treatment of narcolepsy]

This manuscript contains the conclusion of the consensus meeting of the Brazilian Sleep Association with Brazilian sleep specialists on the treatment of narcolepsy based on the review of medical literature from 1980 to 2010. The manuscript objectives were to reinforce the use of agents evaluated in randomized placebo-controlled trials and to issue consensus opinions on the use of other available medications as well as to inform about safety and adverse effects of these medications. Management of narcolepsy relies on several classes of drugs, namely, stimulants for excessive sleepiness, antidepressants for cataplexy and hypnotics for disturbed nocturnal sleep. Behavioral measures are likewise valuable and universally recommended. All therapeutic trials were analyzed according to their class of evidence. Recommendations concerning the treatment of each single symptom of narcolepsy as well as general recommendations were made. Modafinil is the first-line pharmacological treatment of excessive sleepiness. Second-line choices for the treatment of excessive sleepiness are slow-release metylphenidate followed by mazindol. The first-line treatments of cataplexy are the antidepressants, reboxetine, clomipramine, venlafaxine, desvenlafaxine or high doses of selective serotonin reuptake inibitors antidepressants. As for disturbed nocturnal sleep the best option is still hypnotics. Antidepressants and hypnotics are used to treat hypnagogic hallucinations and sleep paralysis.

[Narcolepsy: update on etiology, clinical features and treatment]

Narcolepsy is a disease that involves an alteration in the generation and organisation of sleep. The main symptoms are excessive daytime sleepiness and cataplexy, followed by hypnagogic hallucinations, sleep paralysis and disrupted nocturnal sleep. The prevalence of typical narcolepsy oscillates between 25-50: 100.000 in general. Recently there has been a peak incidence in patients born in the month of March. According to the new classification, the Multiple Sleep Latency Test (MSLT) is mandatory for diagnosing narcolepsy without cataplexy, and advisable for diagnosing narcolepsy with cataplexy. Until now, the attempt has been made to control each symptom by its own specific treatment. At present, new American and European treatment guidelines propose new drugs that act on all the symptoms. The application of new criteria of diagnosis and treatment has improved the diagnosis, giving better options of treatment.

Hypocretin/orexin and narcolepsy: new basic and clinical insights

Narcolepsy is a chronic sleep disorder, characterized by excessive daytime sleepiness (EDS), cataplexy, sleep paralysis and hypnagogic hallucinations. Both sporadic (95%) and familial (5%) forms of narcolepsy exist in humans. The major pathophysiology of human narcolepsy has been recently discovered based on the discovery of narcolepsy genes in animals; the genes involved in the pathology of the hypocretin/orexin ligand and its receptor. Mutations in hypocretin-related genes are rare in humans, but hypocretin ligand deficiency is found in a large majority of narcolepsy with cataplexy. Hypocretin ligand deficiency in human narcolepsy is probably due to the post-natal cell death of hypocretin neurones. Although a close association between human leucocyte antigen (HLA) and human narcolepsy with cataplexy suggests an involvement of autoimmune mechanisms, this has not yet been proved. Hypocretin deficiency is also found in symptomatic cases of narcolepsy and EDS with various neurological conditions, including immune-mediated neurological disorders, such as Guillain-Barre syndrome, MA2-positive paraneoplastic syndrome and neuromyelitis optica (NMO)-related disorder. The findings in symptomatic narcoleptic cases may have significant clinical relevance to the understanding of the mechanisms of hypocretin cell death and choice of treatment option. The discoveries in human cases lead to the establishment of the new diagnostic test of narcolepsy (i.e. low cerebrospinal fluid hypocretin-1 levels for 'narcolepsy with cataplexy' and 'narcolepsy due to medical condition'). As a large majority of human narcolepsy patients are ligand deficient, hypocretin replacement therapy may be a promising new therapeutic option, and animal experiments using gene therapy and cell transplantations are in progress.

Narcolepsy: clinical features, co-morbidities & treatment

Narcolepsy is a neurologic illness that typically begins in the second and third decades of life. It is chronic in nature and negatively impacts the quality of life of affected patients. The classic presentation is a tetrad of excessive daytime sleepiness, cataplexy, sleep paralysis, and hypnagogic hallucinations. The exact cause remains unknown, but there is significant evidence that hypocretin deficiency plays an integral role. Some primary conditions that result in secondary narcolepsy include traumatic brain injury, congenital disorders, tumours, and strokes. Some medical and psychiatric disorders share characteristics of narcolepsy, at times leading to diagnostic inaccuracy. Other sleep disorders are commonly co-morbid. Diagnosis relies on patient history and objective data gathered from polysomnography and multiple sleep latency testing. Treatment focuses on symptom relief through medication, education, and behavioural modification. Both classic pharmacological treatments as well as newer options have significant problems, especially because of side effects and abuse potential. Novel modalities are being examined to expand options for treatment.

[Narcolepsy]

Narcolepsy is a neurologic sleep disorder characterized by excessive daytime sleepiness and by intrusions into wakefulness of physiological aspects of rapid eye movement (REM) sleep such as cataplexy, sleep paralysis and hypnagogic hallucinations. Although epidemiologic studies show that it is nearly as widespread as Parkinson's disease or multiple sclerosis, narcolepsy is often not much known and confused with other neurologic disorders and psychiatric pathologies. The hard psychosocial impact on patient's life can be mitigated by an early diagnosis and by a targeted pharmacological treatment alleviating the most debilitating symptoms. Through a deep assessment of international literature we traced an updated picture of narcoleptic disorder in order to provide a useful tool of neurobiological, clinical, and therapeutic knowledge. Particular attention has been turned to the new discoveries on the possible role of the neuropeptide orexin in the genesis of narcolepsy, which open new pharmacological and research frontiers in this field.

[Narcolepsy]

Narcolepsy is a chronic neurologic disease whose main features are excessive daytime sleepiness and cataplexy. It is a rare disorder which is most frequently sporadic. The age of onset shows tow peaks. Both genetic and environmental factors play in its pathophysiolgy. Association with a specific HLA antigen and implication of the hypocretin system are very important findings. Narcolepsy's diagnosis is based on clinical findings but polysomnographic monitoring and multiple sleep latency test are usually necessary. Treatment of narcolepsy has been substantially modified with the advent of Modafinil which is effective as amphetamine with less undesirable effects. New etiologic treatments, such as hypocretin agonists, are currently being developed.

Therapeutic advances in narcolepsy

Narcolepsy treatment has changed dramatically over the last century. For the treatment of sleepiness in narcolepsy, we have progressed from the early use of caffeine. We have available a variety of different stimulants, and a wake-promoting agent, modafinil, which is widely regarded as the first-line medication for narcolepsy. Cataplexy is managed by medications whereas behavioral treatment, such as avoidance of emotion, was the only treatment available in the past. Following the widespread use of antidepressant medications for cataplexy, we now have sodium oxybate, which works by an unknown mechanism but is the only Food and Drug Administration (FDA)-approved medication for cataplexy. We also recognize that other sleep disorders can occur in narcolepsy, such as obstructive sleep apnea syndrome or rapid eye movement sleep behavior disorder, and new treatments allow these comorbid conditions to be effectively treated. However, although we cannot cure narcolepsy, the current treatments for excessive sleepiness and cataplexy can be effective for many patients. We are improving the quality of life for our patients without producing clinically significant adverse effects. We need new therapeutic advances and several medications that work, though different mechanisms are likely to be available in the near future.

Recent advances in the treatment and management of excessive daytime sleepiness

Excessive daytime sleepiness (EDS) is a prevalent complaint among patients in psychiatric care. Patients with conditions of EDS have often been misdiagnosed with depression due to their complaints of lack of energy, poor concentration, memory disturbance, and a reduced interest in life. Impaired alertness associated with EDS can be detrimental to a person's quality of life by causing decreased work performance, self-consciousness, low self esteem, and social isolation. Excessive sleepiness is also associated with various health problems, comorbid medical and psychiatric conditions, and fatal accidents occurring after the driver has fallen asleep at the wheel. Contributing factors leading to EDS range from insufficient sleep hours to central nervous system-mediated debilitating hypersomnolence. Circadian rhythm disorders, sleep disorders such as obstructive sleep apnea and narcolepsy, and medications that cause sleepiness may also contribute to symptoms of EDS. Recognition of the symptoms of sleep deprivation is essential, as many such patients do not have a clear awareness of their own sleepiness. Treatment options, depending upon the condition, include light therapy or appropriate airway management techniques such as nasal continuous positive airway pressure (CPAP). Occasionally, wakefulness-promoting medications are necessary, particularly in patients with narcolepsy. In this expert roundtable supplement, Stephen P. Duntley, MD, reviews the definition and prevalence of EDS and discusses the contributing factors and consequences of daytime sleepiness. Next, Richard K. Bogan, MD, FCCP, gives an overview of the differential diagnosis of EDS and the assessment tools available for identifying sleepiness in symptomatic patients. Finally, Mary B. O'Malley, MD, PhD, reviews treatment of EDS, including counseling on sleep hygiene and duration of sleep, mechanical treatments, bright-light therapy, and wake-promoting medications.

[Hypersomnia: diagnosis, classification and treatment]

Hypersomnia or excessive daytime sleepiness is common in neurological practice and may have different etiologies. Hypersomnia may be defined as sleepiness at an inappropriate time or in an inappropriate situation. It is important to consider that hypersomnia is at times referred to as tiredness or fatigue. A detailed clinical history is essential to reach an accurate diagnosis. A correct diagnosis is necessary to initiate the appropriate treatment considering the negative social and occupational consequences of hypersomnia. Excessive daytime sleepiness syndromes include primary sleep disorders like narcolepsy and hypersomnia secondary to several neurological and psychiatric disorders and also as an adverse effect of numerous drugs.

Narcolepsy and the hypocretin system--where motion meets emotion

Narcolepsy is a neurological disorder that is characterized by excessive daytime sleepiness and cataplexy--a loss of muscle tone generally triggered by certain strong emotions with sudden onset. The underlying cause of most cases of human narcolepsy is a loss of neurons that produce hypocretin (Hcrt, also known as orexin). These cells normally serve to drive and synchronize the activity of monoaminergic and cholinergic cells. Sleepiness results from the reduced activity of monoaminergic, cholinergic and other cells that are normally activated by Hcrt neurons, as well as from the loss of Hcrt itself. Cataplexy is caused by an episodic loss of activity in noradrenergic cells that support muscle tone, and a linked activation of a medial medullary cell population that suppresses muscle tone. Current treatments for narcolepsy include stimulants to combat sleepiness and antidepressants to reduce cataplexy. Sodium oxybate produces both reductions in cataplexy and improved waking alertness. Future treatments are likely to include Hcrt or Hcrt agonists to reverse the underlying neurochemical deficit.