Hypersomnias of Central Origin

Sleepiness in Adolescents

Sleepiness and sleep deprivation among adolescents are increasingly being recognized as a public health concern. Many of the determinants of this growing problem lie beyond the biomedical scope of explanation. In this article, the authors begin with a review of the prevalence and consequences of sleepiness in adolescents and then present the approach to a sleepy adolescent and the underlying cause. The topic is discussed from clinical as well as public health perspectives.

miRNA profiles in plasma from patients with sleep disorders reveal dysregulation of miRNAs in narcolepsy and other central hypersomnias

STUDY OBJECTIVES

MicroRNAs (miRNAs) have been implicated in the pathogenesis of human diseases including neurological disorders. The aim is to address the involvement of miRNAs in the pathophysiology of central hypersomnias including autoimmune narcolepsy with cataplexy and hypocretin deficiency (type 1 narcolepsy), narcolepsy without cataplexy (type 2 narcolepsy), and idiopathic hypersomnia.

DESIGN

We conducted high-throughput analysis of miRNA in plasma from three groups of patients-with type 1 narcolepsy, type 2 narcolepsy, and idiopathic hypersomnia, respectively-in comparison with healthy controls using quantitative real-time polymerase chain reaction (qPCR) panels.

SETTING

University hospital based sleep clinic and research laboratories.

PATIENTS

Twelve patients with type 1 narcolepsy, 12 patients with type 2 narcolepsy, 12 patients with idiopathic hypersomnia, and 12 healthy controls.

MEASUREMENTS AND RESULTS

By analyzing miRNA in plasma with qPCR we identified 50, 24, and 6 miRNAs that were different in patients with type 1 narcolepsy, type 2 narcolepsy, and idiopathic hypersomnia, respectively, compared with healthy controls. Twenty miRNA candidates who fulfilled the criteria of at least two-fold difference and p-value < 0.05 were selected to validate the miRNA changes in an independent cohort of patients. Four miRNAs differed significantly between type 1 narcolepsy patients and healthy controls. Levels of miR-30c, let-7f, and miR-26a were higher, whereas the level of miR-130a was lower in type 1 narcolepsy than healthy controls. The miRNA differences were not specific for type 1 narcolepsy, since the levels of the four miRNAs were also altered in patients with type 2 narcolepsy and idiopathic hypersomnia compared with healthy controls.

CONCLUSION

The levels of four miRNAs differed in plasma from patients with type 1 narcolepsy, type 2 narcolepsy and idiopathic hypersomnia suggesting that alterations of miRNAs may be involved in the pathophysiology of central hypersomnias.

Nonrespiratory sleep disorders found in ICU patients

Intensive care subjects the critically ill patient to a multitude of stressors caused by the severity of illness and the use of invasive treatment modalities and medications. The ICU environment contributes significant stress of its own related to noise, light, 24-hour patient care, and other factors that disturb sleep. Consequently, various sleep pathologies may emerge or worsen in the ICU patient. Some sleep disorder symptomatology may be confused with serious neurologic complications of critical illness and lead to inappropriate testing or treatment, particularly in the patient who has narcolepsy. Given the high prevalence of sleep disorders in the general population, it is essential that the ICU practitioner attain an adequate knowledge of sleep and its disorders.