Narcolepsy with long sleep time: a specific entity?
BACKGROUND
The classical narcolepsy patient reports intense feelings of sleepiness (with/out cataplexy), normal or disrupted nighttime sleep, and takes short and restorative naps. However, with long-term monitoring, we identified some narcoleptics resembling patients with idiopathic hypersomnia.


OBJECTIVE
To isolate and describe a new subtype of narcolepsy with long sleep time).


METHODS
University Hospital


METHODS
Controlled, prospective cohort


METHODS
Out of 160 narcoleptics newly diagnosed within the past 3 years, 29 (18%) had a long sleep time (more than 11 h/24 h). We compared narcoleptics with (n = 23) and without (n = 29) long sleep time to 25 hypersomniacs with long sleep time and 20 healthy subjects.


METHODS
Patients and controls underwent face-to face interviews, questionnaires, human leukocyte antigen (HLA) genotype, an overnight polysomnography, multiple sleep latency tests, and 24-h ad libitum sleep monitoring.


RESULTS
Narcoleptics with long sleep time had a similar disease course and similar frequencies of cataplexy, sleep paralysis, hallucinations, multiple sleep onset in REM periods, short mean sleep latencies, and HLA DQB1*0602 positivity as narcoleptics with normal sleep time did. However, they had longer sleep time during 24 h, and higher sleep efficiency, lower Epworth Sleepiness Scale scores, and reported their naps were more often unrefreshing. Only 3/23 had core narcolepsy (HLA and cataplexy positive).


CONCLUSIONS
The subgroup of narcoleptics with a long sleep time comprises 18% of narcoleptics. Their symptoms combine the disabilities of both narcolepsy (severe sleepiness) and idiopathic hypersomnia (long sleep time and unrefreshing naps). Thus, they may constitute a group with multiple arousal system dysfunctions.
Vernet
Cyrille
C
Sleep disorder unit, National reference center for narcolepsy and hypersomnia, Pitié-Salpêtrière hospital, Paris 6 University and INSERM UMRS 975, Paris, France.
Arnulf
Isabelle
I
D000328:Adult; D015331:Cohort Studies; D015897:Comorbidity; D003937:Diagnosis, Differential; D006970:Disorders of Excessive Somnolence / Q000175:diagnosis / Q000453:epidemiology*; D005260:Female; D006680:HLA Antigens / Q000032:analysis; D006801:Humans; D007407:Interviews as Topic; D008297:Male; D009290:Narcolepsy / Q000175:diagnosis* / Q000453:epidemiology*; D017286:Polysomnography / Q000379:methods / Q000706:statistics & numerical data; D011446:Prospective Studies; D012894:Sleep Stages; D012895:Sleep, REM; D011795:Surveys and Questionnaires; D014851:Wakefulness
D006680:HLA Antigens