DOES HYPERVENTILATION PROVOKE EPILEPTIFORM ACTIVITY IN EEG?
Abstract number :
2.142
Submission category :
Year :
2003
Submission ID :
490
Source :
www.aesnet.org
Presentation date :
12/6/2003 12:00:00 AM
Published date :
Dec 1, 2003, 06:00 AM
Authors :
Asanka S. Dewaraja, Sampsa Vanhatalo, Mark D. Holmes Department of Neurology, University of Washington, Seattle, WA; Department of Biosciences, University of Helsinki, Helsinki, Finland
Voluntary hyperventilation has been advocated for many decades as an [ldquo]activating[rdquo] procedure to provoke clinical seizures and epileptiform discharges in subjects with suspected epilepsy who undergo standard EEG recordings. This study was undertaken to determine the effects of hyperventilation in patients with proven epilepsy.
We examined the records of 433 consecutive patients with proven epilepsy, as documented by longterm EEG video monitor studies, who underwent five minutes of voluntary hyperventilation during standard EEG recordings. All EEGs were interpreted by board-certified electroencephalographers. The patients ranged in age from 10-64 years; 384 (88.7%) had localized-related and 48 (11.3%) generalized epilepsy syndromes.
Hyperventilation was associated with a clinical seizure in two (0.46%) of the subjects (partial seizures in both cases). Interictal epileptiform discharges were interpreted by showing in increase in frequency during hyperventilation in 19 patients (4.4%), when compared to the baseline EEG.
Our study with the large, unselected population of patients with unequivocal epilepsy, shows that hyperventilation is very rarely associated with either clinical seizures or an increase in frequency of epileptiform discharges. This observation calls for revisiting the current textbook concepts, which are based on small series of selected populations.