Effect of hyperventilation on seizure activation: potentiation by antiepileptic drug tapering.

Objective: To determine prospectively the efficacy of hyperventilation (HV) to activate epileptic seizures and the contribution of antiepileptic drug tapering.

Methods: Eighty patients with proven epilepsy and referred for long-term video-EEG monitoring were consecutively enrolled from November 2007 to December 2008. A seizure was considered as 'activated' if it occurred during HV or within 5 min after completion.