Post-ictal alpha activity in supplementary motor seizures mimics nonepileptic seizures

Supplementary motor area seizures may present with bilateral tonic–clonic movements with no loss of consciousness and no postictal confusion, and patients may be erroneously thought to have psychogenic nonepileptic seizures. We describe the rapid emergence of alpha activity in the immediate postictal period in patients with supplementary motor area seizures as an additional confounding factor that may lead to the erroneous diagnosis of nonepileptic seizures in these patients. We present two cases of patients with intractable supplementary motor area seizures investigated with video/EEG monitoring. Their postictal EEG records revealed an immediate postictal recovery of alpha activity, mimicking the pattern seen with psychogenic nonepileptic seizures. Prolonged video/EEG monitoring is mandatory in establishing the diagnosis of supplementary motor area seizures and in distinguishing this condition from nonepileptic seizures.