Periodic lateralized epileptiform discharges--long-term outcome in adults.

We reviewed the long-term outcome of 39 adults whose electroencephalograms (EEGs) showed acute periodic lateralized epileptiform discharges (PLEDs). Parameters studied included outcome, presence or absence of a seizure disorder (both prior to and subsequent to the PLEDs), seizure type and frequency, and etiology of the PLEDs. The mortality rate was 41%, as 16 of 39 patients died during their hospitalization or within 2 months of discharge. Of the 23 survivors, 7 (30%) had a significant decline in their ability to provide self-care. A recent stroke (13 patients, 33%) was the most frequent cause of PLEDs. In this subgroup particularly, poor outcome, i.e., death or functional decline, was common (10 of 13 patients). Thirty-six patients had seizures just prior to or during the hospitalization when PLEDs were observed; focal motor seizures were the most common type (n = 22). Patients with a history of seizures prior to the occurrence of PLEDs continued to have seizures following discharge. In addition, 4 of 9 patients with new onset seizures associated with PLEDs had subsequent seizures.