Vigilance level-dependent tonic seizures--epilepsy or sleep disorder? A case report.

A case with vigilance level-dependent, nightly occurring, generalized, axial, tonic motor seizures without any ictal or interictal scalp electroencephalographic expression is presented. A pathological sleep pattern with many arousals, superficial sleep, and an interrelation between the seizures and the arousal episodes was demonstrated. An epileptic excitation discharge during the seizures was verified on the right cingular cortex by stereoencephalography. The physiopathogenesis and differential diagnostic problems in the interpretation of such cases as a sleep disorder or an epileptic mechanism are discussed.