The clinical features and EEGs of 45 consecutive patients (40 adults and 5
children) who had periodic lateralized epileptiform discharges (PLEDs) were
reviewed to determine the relationship between seizures and PLEDs. Focal e
ncephalitis and ischemic stroke were the most frequent underlying processes
for adult patients. All of the children, but only six of the adults, had l
ong-lasting cerebral disorders whereas the remaining adults had acute or su
bacute illness. There were 38 patients (84.4%) experiencing a seizure disor
der. Twenty-six of them had their first seizure during their acute illness,
as the pattern of PLED was encountered. Eight cases had status epilepticus
, and seven of them had epilepsia partialis continue. Nineteen patients had
a recent seizure in the day when PLEDs were observed hut not during EEG re
cording; 12 patients had their seizures within 10 days before the observati
on of PLED. PLEDs were grouped into three categories with respect to their
extensions: lateralized to one hemisphere (n = 22), localized in one region
(n = 17) and being prominent over one side with contralateral spread (n =
6). The last group was found to be more closely associated with frequent se
izures or status epilepticus than the other two groups, our results showed
that PLEDs were highly correlated with recent seizures in the majority of t
he patients. These EEG findings may be considered as a manifestation of an
increased neuronal excitability caused by different etiologies; but not an
ictal pattern. (C) 2000 BEA Trading Ltd.