Local Sleep in Idiopathic Hypersomnia

Sleeping With Open Eyes: Local Sleep in Idiopathic Hypersomnia

Idiopathic hypersomnia (IH) is a rare and poorly studied disease characterized by excessive daytime sleepiness different from that of narcolepsy (sleep drunkness non-recuperative naps and nocturnal blackout). Local sleep is a recent concept, proposing a local regulation of the sleep-wake state, characterized by slow waves (SW) restricted to certain regions of a globally awake brain. The investigators are going to investigate whether local sleep could explain the sleepiness of these patients better than the global occurrence of sleep which are not very frequent during daytime tests in IH.

The investigators propose to look for local sleep through the detection of local slow waves in the EEG of resting wakefulness and during an attentional task in people with IH compared to people with NT1 (sleepy, but with a different type of sleepiness from IH, more abrupt and including REM sleep) and non sleepy people.

Local sleep is a recent concept, suggesting a local regulation of the sleep-wake state, characterized for example in wakefulness by slow waves restricted to certain regions of a globally awake brain, correlating with modifications of mental experience and behavior. Although the phenomenon of local sleep has been demonstrated following acute sleep deprivation, its importance in explaining attentional fluctuations during a normal day is only beginning to be investigated. Moreover, inter-individual variations remain unexplored. The investigators propose to study in EEG (64 electrodes) the occurrence of local sleep in different states of sleepiness, in particular in idiopathic hypersomnia (IH) in comparison to that of narcolepsy type 1 (NT1) and to non-drowsy individuals, both in the resting state and during a sustained attention test (SART). This study will provide a better understanding of intra- (over the course of a day) and inter-individual fluctuations in the local sleep phenomenon potentially involved in this disease and its impact on cognition.

Anticipated number of participants:

60 including:

• 20 people with idiopathic hypersomnia
• 20 people with type 1 narcolepsy
• 20 people with no previous history

Practical procedure:

Single visit: presence from 9:30 am to 3:30 pm

• General questionnaire on sleep habits and symptoms.
• Equipment: EEG 32 electrodes, EOG, ECG, eye tracker and thoracoabdominal belts.
• Morning and afternoon recording: 10 minutes in resting state, 60 minutes of digital SART (go-no-go test in front of a screen, with intermittent evaluation of mental state), then 10 minutes of rest.

Inclusion Criteria:

Inclusion Criteria :

• Healthy subjects and people with IH and NT1:

  ->18 years old, of both sexes, without legal protection.

  • Affiliated to the French social security system
  • Signature of free and informed consent
  • Fluency in spoken and written French

• Specific to people with IH:

  -Diagnosis of IH according to the ICSD-3, already made in the sleep pathology department of the Pitié after a specialized medical interview and a standardized 48h assessment (Night 1+TILE+Night 2+two naps): Sleep time > 660 min or TILE latency <8 min, <2 SOREMPs.

• Specific to people with NT1:

  • Diagnosis of narcolepsy type 1 according to the ICSD-3, already made in the sleep pathology department of the Pitié after a specialized medical interview and a standardized 48h workup (Night 1+TILE+Night 2+two naps) and sometimes a lumbar puncture: hypocretin <110 pmol/L in CSF or cataplexy and TILE latency <8 min, >1 SOREMP.

Exclusion Criteria:

• Shift or night work
• Sleep debt on the day of the recording (questioning and sleep diary one week before the recording)
• Other sleep pathology causing daytime sleepiness (sleep apnea, insomnia, parasomnia for example)
• Cerebral neurological pathology
• Depressive episode
• Any psychotropic treatment modifying the EEG structure
• Failure to wean from arousing treatment on the day of the test.
• Inability to travel by transport or to be transported by a relative on the day of the recording.