Generalized cortical electrodecremental event. Clinical and neurophysiological observations in patients with dystonic seizures.

Patients with seizures accompanied by generalized cortical electrodecremental event (CEE) have clusters of clinical spells with tonic, dystonic, or atonic components and involvement of autonomic functions. When electroencephalographically detectable foci are present, they behave in a peculiar way; throughout the entire cluster of seizures focal spiking is reduced in the short interictal periods as well as during each individual seizure with CEE, at which time it is suppressed. Focal firing reappears reinforced at the end of each spell and also at the end of the cluster. These facts suggest that the foci responsible for CEE are deeply located. A complex excitatory-inhibitory feedback probably exists between cortical and subcortical foci. These seizures should be differentiated from similar attacks of nonepileptic or epileptic nature. A correct diagnosis is essential given the different therapeutic implications.