Structural Lesions in Periodic Lateralized Epileptiform Discharges (PLEDs)

In this study we investigated the structural lesions of patients with periodic lateralized epileptiform discharges (PLEDs) to determine the possible relationship of lesions to PLEDs' localization on EEG and to metabolic abnormality. Clinical findings and electroencephalography (EEG), computerized tomography (CT) and magnetic resonance imaging (MRI) of the 71 adult patients with PLEDs were evaluated. Stroke, herpes encephalitis and intracranial tumor or abscess were the most common etiological factors. Cortical gray matter and adjacent subcortical white matter lesions were detected in 64.7%, cortical gray matter lesions in 11.3% and subcortical white matter lesions in 4.2% of the patients. Although it is thought that PLEDs occur mostly with acute lesions, chronic lesions causing PLEDs were found in 35.2% of the patients. Bilateral lesions were detected in 19.7% and 33.8% of the patients had metabolic abnormality. PLEDs localized the region of the lesion in 63.4% of the patients. PLEDs are usually self-limited features, but chronic PLEDs were detected in 5 patients in this study. Acute structural lesions involving cortical gray matter with adjacent subcortical white matter were found in most of the patients with PLEDs, but the lesion localization and age, acute or chronic, varied.