Hypocretin (orexin) deficiency predicts severe objective excessive daytime sleepiness in narcolepsy with cataplexy

• Published in: Journal of neurology, neurosurgery and psychiatry Vol. 77; no. 3; pp. 402 - 404
• Main Authors: Baumann, C R, Khatami, R, Werth, E, Bassetti, C L
• Format: Journal Article
• Language: English
• Published: London BMJ Publishing Group Ltd 01.03.2006; BMJ; BMJ Publishing Group LTD; BMJ Group
• Subjects: Adolescent; Adult; Biological and medical sciences; cataplexy; Cataplexy - cerebrospinal fluid; Cataplexy - diagnosis; cerebrospinal fluid; CSF; detectable hypocretin; Diseases of striated muscles. Neuromuscular diseases; Disorders of Excessive Somnolence - cerebrospinal fluid; Disorders of Excessive Somnolence - diagnosis; EDS; Epworth Sleepiness Scale; ESS; excessive daytime sleepiness; Female; Hallucinations; Humans; hypersomnia; hypocretin; Insomnia; Intracellular Signaling Peptides and Proteins - deficiency; Investigative techniques of ocular function and vision; Investigative techniques, diagnostic techniques (general aspects); Male; mean sleep latency; Medical sciences; Middle Aged; MSL; MSLT; multiple sleep latency test; Narcolepsy - cerebrospinal fluid; Narcolepsy - diagnosis; Neurology; Neuropeptides - deficiency; orexin; Orexins; Polysomnography; Predictive Value of Tests; Prognosis; PSG; Short Report; Sleep disorders; sleep onset REM period; Sleep Propensity in Active Situations; Sleep, REM - physiology; SNS; SOREMP; SPAS; Swiss narcolepsy scale; Ullanlinna Narcolepsy Scale; undetectable hypocretin; UNS; Sleep disorder; Nervous system diseases; Narcolepsy; Neurological disorder; Deficiency; Cataplexy
• DOI: 10.1136/jnnp.2005.067207
• ISSN: 0022-3050

Cerebrospinal fluid (CSF) hypocretin-1 deficiency is associated with definite (“clear cut”) cataplexy in patients with narcolepsy. The relationship between CSF hypocretin-1 levels and other narcoleptic symptoms (including excessive daytime sleepiness, EDS) is not properly understood. In a consecutive series of 18 subjects with narcolepsy and definite cataplexy, patients with undetectable CSF hypocretin-1 (n = 12) were found to have significantly lower mean sleep latencies (p = 0.045) and a higher frequency of sleep onset REM periods (SOREMPs, p = 0.025) on multiple sleep latency test than patients (n = 6) with detectable levels. Conversely, Epworth sleepiness scale scores, the frequency of hallucinations/sleep paralysis, and the frequency and severity of cataplexy were similar in both groups. These results suggest that hypocretin deficiency identifies a homogenous group of patients with narcolepsy characterised by the presence of definite cataplexy, severe EDS, and frequent SOREMPs.