Persons with narcolepsy with cataplexy have low levels of cerebrospinal fluid (CSF) hypocretin-1, a protein thought to help regulate sleep and wakefulness, according to a study published in the August 1st issue of the journal SLEEP.
The study, authored by Mona Skard Heier, MD, PhD, of Ullev'l University Hospital in Oslo, Norway, focused on 64 previously diagnosed patients: 47 with narcolepsy with cataplexy, seven with narcolepsy without cataplexy and 10 with idiopathic central nervous system (CNS) hypersomnia, a condition characterized by recurrent daytime sleepiness without the abrupt sleep attacks classically seen in narcolepsy. The patients answered a questionnaire that asked about sleep habits, daytime sleepiness, accessory symptoms, duration and treatment.
Low hypocretin-1 values were found in 72 percent of those patients with narcolepsy and cataplexy. Patients with low CSF hypocretin-1 levels reported more extensive muscular involvement during cataplectic attacks than patients with normal levels.
Patients with narcolepsy without cataplexy and idiopathic CNS hypersomnia all had normal hypocretin-1 levels. No significant clinical or biochemical differences were found between these patient groups.