title: Periodic epileptiform discharges in mesial temporal lobe epilepsy with hippocampal sclerosis.
abstract: OBJECTIVE
  Periodic epileptiform discharges (PEDs) are an uncommon, abnormal EEG pattern seen usually in patients with acute diseases and less frequently in chronic conditions, such as mesial temporal lobe epilepsy (mTLE). Evaluate the clinical histories, neuroimaging findings, and serial electrophysiological studies prior to the appearance of PEDs in patients with mTLE secondary to hippocampal sclerosis (HS).
  
  
  METHODS
  We searched 19, 375 EEGs (2006-2012) for the presence of PEDs secondary to mTLE due to HS.
  
  
  RESULTS
  12 patients were included. The patients with PEDs had a high prevalence of psychiatric comorbilities, including major depression (50%), interictal psychosis (16%) and dementia (8%). All of the patients had intractable epilepsy with similar clinical findings. We observed a sequential neurophysiological worsening of the EEG patterns prior to the appearance of PEDs. Five patients with PEDs underwent epilepsy surgery and four were seizure free at follow-up 15 (±9) months.
  
  
  CONCLUSIONS
  PEDs are rare in patients with mTLE and HS and their presence in these cases could reflect clinical severity and neurophysiologic worsening, clinically manifested by intractable epilepsy and severe psychiatric comorbidities. The presence of PEDs in EEGs of patients with mTLE, however, was not associated with poor postsurgical seizure-freedom.
authors.affiliation: Neurophysiology Service, National Institute of Neurology, Mexico; Centro Neurológico, Centro Médico ABC, Santa Fe, Mexico. Electronic address: pegaso31@yahoo.com.
authors.forename: Daniel
authors.initials: D
authors.lastname: San-Juan
authors.forename: Adriana Patricia M
authors.initials: AP
authors.lastname: Mayorga
authors.forename: Juan de Dios Del Castillo
authors.initials: Jde D
authors.lastname: Calcáneo
authors.forename: Maricarmen Fernández
authors.initials: MF
authors.lastname: González-Aragón
authors.forename: Mario
authors.initials: M
authors.lastname: Alonso-Vanegas
authors.forename: Carolina Domínguez
authors.initials: CD
authors.lastname: Rico
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Staba
authors.forename: David J
authors.initials: DJ
authors.lastname: Anschel
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Cole
mesh_terms: D000328:Adult; D000368:Aged; D058256:Brain Waves / Q000502:physiology*; D004569:Electroencephalography; D004833:Epilepsy, Temporal Lobe / Q000503:physiopathology*; D005260:Female; D006624:Hippocampus / Q000473:pathology / Q000503:physiopathology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012598:Sclerosis / Q000209:etiology
keywords: Hippocampal sclerosis; Mesial temporal lobe epilepsy; Outcome; PLEDs; Periodic epileptiform discharges; Seizures