title: Electro-clinical and imaging characteristics of focal cortical dysplasia: correlation with pathological subtypes.
abstract: BACKGROUND
  Focal cortical dysplasia (CD) is a common cause of pharmaco-resistant epilepsy. CD is due to abnormalities in neuronal migration, proliferation, and/or differentiation that result in four distinct pathological subtypes: 1A, 1B, 2A, and 2B. In order to provide clinical correlation to these pathological subtypes, we reviewed the electro-clinical and imaging characteristics and surgical outcomes of the four pathological subtypes of CD.
  
  
  METHODS
  We retrospectively reviewed patient data from epilepsy surgeries at the Cleveland Clinic Foundation between 1990 and 2002. Only those patients with the definite pathological diagnosis of isolated cortical dysplasia were included in the study (n = 145).
  
  
  RESULTS
  Pathological subtypes 2A and 2B were predominantly frontal in location, and had a more severe epilepsy syndrome with lower intelligence quotient scores than subtypes 1A and 1B. Patients with subtype 1A FCD had less severe, later onset epilepsy that was predominantly located in the temporal lobe. Risk factors for epilepsy included febrile seizures for type 1A, head trauma for types 1A and 1B, and perinatal adverse events for type 2B. Type 2B demonstrated significantly more FLAIR signal abnormalities than the other groups. Sixty-three percent of patients overall had an Engel I outcome at 6 months follow-up. The best outcomes were in the 2B subtype, and in those who did not require an invasive EEG evaluation.
  
  
  CONCLUSIONS
  Clinically important differences exist between the pathological subtypes of CD, which may assist in their management, and provide further insight into their underlying pathophysiology.
authors.affiliation: Section of Epilepsy, Department of Neurology, The Cleveland Clinic Foundation, 9500 Euclid Avenue, S51, Cleveland, OH 44195, USA.
authors.forename: Peter
authors.initials: P
authors.lastname: Widdess-Walsh
authors.forename: Christoph
authors.initials: C
authors.lastname: Kellinghaus
authors.forename: Lara
authors.initials: L
authors.lastname: Jeha
authors.forename: Prakash
authors.initials: P
authors.lastname: Kotagal
authors.forename: Richard
authors.initials: R
authors.lastname: Prayson
authors.forename: William
authors.initials: W
authors.lastname: Bingaman
authors.forename: Imad M
authors.initials: IM
authors.lastname: Najm
mesh_terms: D000293:Adolescent; D000328:Adult; D002540:Cerebral Cortex / Q000002:abnormalities* / Q000473:pathology*; D002648:Child; D002675:Child, Preschool; D004569:Electroencephalography; D004827:Epilepsy / Q000473:pathology* / Q000601:surgery; D005500:Follow-Up Studies; D006801:Humans; D008279:Magnetic Resonance Imaging; D012189:Retrospective Studies; D012720:Severity of Illness Index; D016896:Treatment Outcome