Narcolepsy with long sleep time: a specific entity?

Cyrille Vernet and Isabelle Arnulf

This is my second paper accepted in SLEEP

Background: The classical narcolepsy patient reports intense feelings of sleepiness (with/out cataplexy), normal or disrupted night-time 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.

Setting: University Hospital

Design: Controlled, prospective cohort

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

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

Results: Narcoleptics with long sleep time had a similar disease course, and evidenced 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 hours, and higher sleep efficiency, lower Epworth sleepiness score and more often unrefreshing naps. Only 3/23 had a ‘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.

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 Idiopathic hypersomnia with and without long sleep time: a controlled series of 75 patients

 Cyrille Vernet and Isabelle Arnulf

I'm glad to present my first accepted paper in SLEEP

Objective: To characterize the clinical, psychological, and sleep pattern of idiopathic hypersomnia with
and without long sleep time, and provide normative values for 24-hour polysomnography.

Setting: University Hospital

Design: Controlled, prospective cohort

Participants: 75 consecutive patients (aged 34±12 y) with idiopathic hypersomnia and 30 healthy matched controls.

Intervention: Patients and controls underwent during 48 hours a face-to face interview, questionnaires, human leukocyte antigen genotype, a night polysomnography and multiple sleep latency test (MSLT), followed by 24-hour ad libitum sleep monitoring.

Results: Hypersomniacs had more fatigue, higher anxiety and depression scores, and more frequent hypnagogic hallucinations (24%), sleep paralysis (28%), sleep drunkenness (36%) and un-refreshing naps (46%) than controls. They were more frequently evening types. DQB1*0602 genotype was similarly found in hypersomniacs (24.2%) and controls (19.2%). Hypersomniacs had more frequent slow wave sleep after 6 AM than controls. During 24-hour polysomnography, the 95% confidence interval for total sleep time was 493-558 min in controls, versus 672-718 min in hypersomniacs. There were 40 hypersomniacs with and 35 hypersomniacs without long (>600 min) sleep time. The hypersomniacs with long sleep time were younger (29±10 vs 40±13 y, P=0.0002), slimmer (body mass index: 26±5 vs 23±4 kg/m2; P=0.005), and had lower Horne-Ostberg scores and higher sleep efficiencies than those without long sleep time. MSLT latencies were normal (>8 min) in 71% hypersomniacs with long sleep time.

Conclusions: Hypersomnia, especially with long sleep time, is frequently associated with evening chronotype and young age. It is inadequately diagnosed using MSLT.

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