Prolonged postictal confusion lasting from four to ten days is reported in 11 patients (ages 7½ to 40 years) from the Epilepsy Research Center, Department of Neurology, University of Minnesota and MINCEP Epilepsy Care, P.A., Minneapolis. Age of seizure onset averaged 10.7 years. The remote etiology was meningitis in 5, trauma 2, genetic 1, and birth anoxia 1. Mild to borderline mental retardation was present in nine and nine had nonspecific structural abnormalities on MRI or CT, including mild cortical atrophy and mild ventricular enlargement. Previous episodes of status epilepticus had occurred in ten. The encephalopathy always occurred after a cluster of seizures which were generalized tonic-clonic in eight, complex partial in two, and atypical absence in one. The patient with absence seizures, a girl aged 7½, would regress into what mother described as an “infantile stage” after each cluster of seizures lasting a period of a week. During this stage which persisted seven to ten days she would not be able to talk, sit, walk, feed herself, or even chew food placed in her mouth. She was awake and would respond very slowly. Repeated loads of diazepam, valproic acid, ethosuximide, and methsuximide did not result in any clinical or EEG improvement. Metabolic drug toxicity as well as ongoing nonconvulsive status was ruled out as the cause of the confusional state. 
COMMENT. This study demonstrates the adverse effects of repetitive seizures on the state of consciousness and mentation, particularly in patients who have previously experienced status epilepticus. The lack of response of this confusional state to anticonvulsant drugs is documented but the details of treatment and serum levels of anticonvulsant medications are not provided. This report suggests that patients who have a tendency to clusters of seizures, mild cerebral atrophy, a history of status epilepticus, and mild to borderline intellectual retardation, are particularly vulnerable to develop transient encephalopathy and are candidates for vigorous and regularly monitored anticonvulsant treatment.