What are periodic lateralized epileptiform discharges on EEG of focal lesions?

Updated: Aug 06, 2019
  • Author: Selim R Benbadis, MD; Chief Editor: Helmi L Lutsep, MD  more...
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Described in 1964 by Chatrian et al, periodic lateralized epileptiform discharges (PLEDS) are a special type of focal abnormality. [2, 3] As implied by their name, they are periodic, lateralized, and epileptiform. Periodicity is the most characteristic feature, and the one that sets PLEDS apart from other focal abnormalities. Periodicity refers to a relatively constant interval between discharges, which varies between 0.5 and 3 seconds and most often is around 1 second. The epileptiform morphology of the discharges is not invariable, as PLEDS are often closer to slow waves than to sharp waves in morphology.

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