Abstracts

Rationale: Periodic lateralized epileptiform discharges (PLEDs) are rare and abnormal electroencephalographic patterns seen usually in patients with acute diseases. However, these phenomena can also be observed in patients with chronic neurological conditions. Some authors have postulated that chronic PLEDs may be a different entity from the acute type, but the information is lacking. Therefore, the objective of the present study was to describe and compare the clinical, neurophysiological and neuroimaging findings and prognosis of PLEDs in acute and chronic neurologic diseases. Methods: Descriptive, retrospective and multicenter study. One hundred fifteen patients were identified (2000-2009) in two centers; 95 PLEDs were included. Statistical analysis: Descriptive and inferential analyses were used. Logistical regression and likelihood models were developed. Results: Death and functional dependence were most frequent for PLEDs due to acute disease. For PLEDs due to chronic conditions, epilepsy development (OR 10.98 [3.7 - 32.53]), normal physical exam (OR 0.54 [0.31 - 0.94]) and vascular etiology (OR 0.64 [0.47 0.86]) were related to functional dependency. A longer duration of epileptiform complexes was associated to dependency (OR 1.05 [1.01 - 1.08]) and death (OR 1.05 [1.00 - 1.09]); a longer duration of the inter-PLEDs interval (OR 0.98 [0.97 - 0.99]) and periodic complex amplitude (OR 1.18 [1.04 - 1.35]) were more associated with an independent functional outcome.Conclusions: PLEDs due to chronic conditions, development of epilepsy, normal physical exam and vascular etiology are related to functional independency. Longer duration of epileptiform periodic complexes is associated to dependency or death.