title: Serial polysomnography in hypnic headache.
abstract: BACKGROUND
  Hypnic headache (HH) is a rare primary headache disorder characterized by strictly sleep-related headache attacks. Most patients are over the age of 50 and usually awake at the same time at night with dull bilateral head pain. The pathophysiology of this headache disorder is still enigmatic but association with rapid eye movement (REM) sleep and sleep-disordered breathing (SDB) has been suggested.
  
  
  METHODS
  Six patients with HH according to the current International Classification of Headache Disorders (ICHD-II) criteria (code 4.5) were investigated. Serial polysomnography (PSG) was performed in each patient for four consecutive nights.
  
  
  RESULTS
  A total of 22 HH attacks were recorded from all patients during PSG. Six of the monitored headache attacks arose from REM sleep; 16 attacks, however, arose from different non-REM (NREM) sleep stages. Five patients showed an increased apnoea/hypopnoea index (>5), indicating obstructive sleep apnoea (OSA) on some but not the majority of nights. Headache onset and occurrence of SDB were not temporally connected.
  
  
  CONCLUSIONS
  This prospective study shows that the onset of HH was not associated with sleep stage. These results contradict the current belief that REM sleep and SDB play a crucial role in the pathophysiology of HH.
authors.affiliation: Department of Neurology, University of Duisburg-Essen, Hufelandstrasse 55, Essen, Germany. dagny.holle@uk-essen.de
authors.forename: Dagny
authors.initials: D
authors.lastname: Holle
authors.forename: Thomas E
authors.initials: TE
authors.lastname: Wessendorf
authors.forename: Sebastian
authors.initials: S
authors.lastname: Zaremba
authors.forename: Steffen
authors.initials: S
authors.lastname: Naegel
authors.forename: Hans-Christoph
authors.initials: HC
authors.lastname: Diener
authors.forename: Zaza
authors.initials: Z
authors.lastname: Katsarava
authors.forename: Charly
authors.initials: C
authors.lastname: Gaul
authors.forename: Mark
authors.initials: M
authors.lastname: Obermann
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D051270:Headache Disorders, Primary / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D017286:Polysomnography; D012894:Sleep Stages / Q000502:physiology*