Sleep but not hyperventilation increases the sensitivity of the EEG in patients with temporal lobe epilepsy.
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.
Klein
Karl Martin
KM
Interdisciplinary Epilepsy-Center, Department of Neurology, Neurologische Klinik, Philipps-University Marburg, Rudolf-Bultmann-Str. 8, 35033 Marburg, Germany.
Knake
Susanne
S
Hamer
Hajo M
HM
Ziegler
Andreas
A
Oertel
Wolfgang H
WH
Rosenow
Felix
F
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