title: Hippocampal abnormalities in malformations of cortical development: MRI study.
abstract: OBJECTIVE
  Hippocampal abnormalities may coexist with malformations of cortical development (MCD). This cross-sectional MRI study aimed at categorizing hippocampal abnormalities in a large group of MCD and comparing MCD patients with (group W) and without (group W/O) hippocampal abnormalities.
  
  
  METHODS
  Hippocampal anatomy, rotation, size, internal structure, and MRI signal alterations were assessed visually by 3 independent raters in patients with MCD and epilepsy. Four types of hippocampal abnormalities were examined in 220 patients (116 women, mean age 31 +/- 16.6, range 2-76 years): partially infolded/hypoplastic hippocampus (HH), hippocampal sclerosis (HS), malrotated hippocampus (MH), and enlarged hippocampus (EH). The commonest MCD in the cohort were focal cortical dysplasia (27%), polymicrogyria (PMG) (21%), developmental tumors (15%), and periventricular nodular heterotopia (PNH) (14%).
  
  
  RESULTS
  Hippocampal abnormalities were seen in 69/220 (31%) patients: HH in 34/69 (49%); HS in 18/69 (26%); MH in 15/69 (22%); and EH in 2/69 (3%). PNH (21/30 [70%]) and PMG (22/47 [47%]) were most commonly associated with hippocampal abnormalities. Compared to the W/O group, patients in the W group had a higher rate of learning disability (W 41/69 [59%] vs W/O 56/151 [37%]; p = 0.003) and delayed developmental milestones (W 36/69 [52%] vs W/O 53/151 [35%]; p = 0.025); groups did not differ otherwise with regard to clinical presentation. HH was associated with symptomatic generalized epilepsies (11/34 [32%]) and high rate of learning disability (27/34 [79%]), neurologic deficits (25/34 [73%]), and delayed developmental milestones (23/34 [68%]).
  
  
  CONCLUSIONS
  About a third of patients with malformations of cortical development had hippocampal abnormalities. Patients with hypoplastic hippocampus had the most severe clinical phenotype.
authors.affiliation: Department of Neurology, Medical University of Innsbruck, Innsbruck.
authors.forename: G
authors.initials: G
authors.lastname: Kuchukhidze
authors.forename: F
authors.initials: F
authors.lastname: Koppelstaetter
authors.forename: I
authors.initials: I
authors.lastname: Unterberger
authors.forename: J
authors.initials: J
authors.lastname: Dobesberger
authors.forename: G
authors.initials: G
authors.lastname: Walser
authors.forename: L
authors.initials: L
authors.lastname: Zamarian
authors.forename: E
authors.initials: E
authors.lastname: Haberlandt
authors.forename: H
authors.initials: H
authors.lastname: Maier
authors.forename: M
authors.initials: M
authors.lastname: Ortler
authors.forename: T
authors.initials: T
authors.lastname: Gotwald
authors.forename: E
authors.initials: E
authors.lastname: Gelpi
authors.forename: T
authors.initials: T
authors.lastname: Czech
authors.forename: M
authors.initials: M
authors.lastname: Feucht
authors.forename: G
authors.initials: G
authors.lastname: Bauer
authors.forename: M
authors.initials: M
authors.lastname: Delazer
authors.forename: S
authors.initials: S
authors.lastname: Felber
authors.forename: E
authors.initials: E
authors.lastname: Trinka
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D016009:Chi-Square Distribution; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D004569:Electroencephalography; D005260:Female; D006624:Hippocampus / Q000002:abnormalities* / Q000473:pathology*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007859:Learning Disabilities / Q000473:pathology; D008279:Magnetic Resonance Imaging; D008297:Male; D054220:Malformations of Cortical Development / Q000473:pathology*; D008875:Middle Aged; D009474:Neurons / Q000473:pathology; D009483:Neuropsychological Tests; D009929:Organ Size