title: Sleep but not hyperventilation increases the sensitivity of the EEG in patients with temporal lobe epilepsy.
abstract: OBJECTIVE
  To evaluate the relative impact of 3 and 5 min of hyperventilation (HV) and different sleep stages on the sensitivity of the interictal EEG in focal epilepsy.
  
  
  METHODS
  We examined 20 patients with temporal lobe epilepsy (TLE, 85%) or extratemporal epilepsy during EEG-monitoring. We compared 6 min EEG (12 epochs of 30s) during/after each: (a) waking; (b) 5 or 3 min of HV; (c) sleep stages 1, 2, 3/4 and REM regarding the frequency of epileptiform discharges (ED). The Wilcoxon matched pairs signed rank test was used. The main endpoint was the comparison of 5 min of HV with sleep stage 2.
  
  
  RESULTS
  During sleep stage 2, ED were more frequent than during/after 5 min of HV (P=0.002). Compared to the waking EEG, all NREM-sleep stages activated ED. Sleep stage 2 was associated with the strongest activation. There was no difference between the waking state and REM-sleep. Compared to the waking EEG, neither 3 nor 5 min of HV showed an activation of ED.
  
  
  CONCLUSIONS
  In patients with TLE, sleep stage 2 shows a significantly higher sensitivity for ED than 5 min of HV. Compared to the waking EEG, HV showed no activating effect on ED. These results suggest that in patients with the clinical diagnosis of TLE (and possibly other focal epilepsies) measures to record sleep stage 2 (such as sleep deprivation) should be increased whereas HV appears to be dispensable in this setting.
authors.affiliation: Interdisciplinary Epilepsy-Center, Department of Neurology, Neurologische Klinik, Philipps-University Marburg, Rudolf-Bultmann-Str. 8, 35033 Marburg, Germany.
authors.forename: Karl Martin
authors.initials: KM
authors.lastname: Klein
authors.forename: Susanne
authors.initials: S
authors.lastname: Knake
authors.forename: Hajo M
authors.initials: HM
authors.lastname: Hamer
authors.forename: Andreas
authors.initials: A
authors.lastname: Ziegler
authors.forename: Wolfgang H
authors.initials: WH
authors.lastname: Oertel
authors.forename: Felix
authors.initials: F
authors.lastname: Rosenow
mesh_terms: D000328:Adult; D004569:Electroencephalography; D004833:Epilepsy, Temporal Lobe / Q000503:physiopathology*; D005260:Female; D006801:Humans; D006985:Hyperventilation / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D017286:Polysomnography; D012680:Sensitivity and Specificity; D012894:Sleep Stages / Q000502:physiology*; D013997:Time Factors; D014851:Wakefulness / Q000502:physiology