Does Hyperventilation Elicit Epileptic Seizures?

Authors

  • Mark D. Holmes,

    1. Regional Epilepsy Center, Department of Neurology, University of Washington, Seattle, Washington, U.S.A.
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  • Asanka S. Dewaraja,

    1. Regional Epilepsy Center, Department of Neurology, University of Washington, Seattle, Washington, U.S.A.
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  • Sampsa Vanhatalo

    1. Regional Epilepsy Center, Department of Neurology, University of Washington, Seattle, Washington, U.S.A.
    2. Biosciences
    3. Clinical Neurophysiology, University of Helsinki, Helsinki, Finland
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Address correspondence and reprint requests to Dr. M.D. Holmes at University of Washington Regional Epilepsy Center, Harborview Medical Center, 325 Ninth Avenue, Seattle, WA 98104, U.S.A. E-mail: mdholmes@u.washington.edu

Abstract

Summary: Purpose: Voluntary hyperventilation has been advocated for many decades as an “activating” 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.

Methods: We examined the records of 433 consecutive patients with proven epilepsy, as documented by long-term video-EEG studies. The patients underwent 5 min of voluntary hyperventilation during standard EEG recordings. All EEGs were interpreted by board-certified electroencephalographers. The patients ranged in age from 10 to 64 years; 384 (88.7%) had localization-related and 48 (11.3%) generalized epilepsy syndromes.

Results: Hyperventilation was associated with a clinical seizure in two (0.46%) of the subjects (partial seizures in both cases). Interictal epileptiform discharges were interpreted as showing in increase in frequency during hyperventilation in 19 (4.4%) patients, when compared with the baseline EEG.

Conclusions: Voluntary hyperventilation in patients with unequivocal epilepsy is rarely associated with either clinical seizures or an increase in frequency of epileptiform discharges.

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