Confusional states with periodic lateralized epileptiform discharges (PLEDs): a peculiar epileptic syndrome in the elderly.

The histories of seven patients over the age of 60 years are reported. They all suffered from recurrent and prolonged episodes of confusional state associated with psychic and neurologic manifestations. All episodes were accompanied by the occurrence of periodic lateralized epileptiform discharges (PLEDs) on the EEG, which became normal when the ictal episodes subsided either spontaneously or after administration of diazepam i.v. Although PLEDs may correspond to severe hemispheric lesions, serial computed tomography (CT) scan and laboratory investigations detected significant abnormalities in only one case, that of a patient with a progressive dementing outcome. In the other six patients, follow-up neuropsychological controls indicated moderate impairment of higher cortical functions according to the hemisphere involved by PLEDs. Administration of carbamazepine (CBZ) proved rather effective in preventing the recurrence of the ictal episodes. For its clinical, EEG, and prognostic features, this condition may represent a peculiar nonconvulsive status epilepticus in the elderly.