title: Interictal EEG, hippocampal atrophy, and cell densities in hippocampal sclerosis and hippocampal sclerosis associated with microscopic cortical dysplasia.
abstract: The EEG characteristics of isolated hippocampal sclerosis (HS) and HS associated with other types of temporal lobe pathology are not well defined. The pathologic substrate may be an important variable in determining seizure-free outcome. The objective of this study was to define the distribution of epileptiform discharges in patients with HS and HS associated with microscopic dysplasia, and to examine their relationship with hippocampal atrophy and cell loss. Thirty-four patients (15 women and 19 men; mean age, 30.6 +/- 11.2 years), all with good outcomes after temporal lobectomy (Engel classes I and II), were included. The characteristics studied were frequency and distribution of spikes, MRI-based hippocampal volume ratios, and quantitative hippocampal cell density in various subregions. The isolated HS group showed a trend to a higher percentage of epileptiform discharges maximal at the anterior temporal electrodes (89.87 +/- 17.0%; 79.5 +/- 28.2% in the dual-pathology group). The isolated HS group had, on average, significantly more cell loss (P < 0.001). There was a significant negative correlation between the amount of cell loss in the CA1 area and both anterior temporal spikes and hippocampal ratios (P < 0.05). Isolated HS and dual pathology show minimal differences in interictal spike distribution and frequency. More widespread spike distributions in severe isolated HS compared with patients with less cell loss is probably the result of less organized limbic circuitry.
authors: Department of Neurology, The Cleveland Clinic Foundation, Ohio, USA.
authors: Beate
authors: B
authors: Diehl
authors: Imad
authors: I
authors: Najm
authors: Armin
authors: A
authors: Mohamed
authors: Thomas
authors: T
authors: Babb
authors: Zhong
authors: Z
authors: Ying
authors: William
authors: W
authors: Bingaman
mesh_terms: D000328:Adult; D001284:Atrophy; D002452:Cell Count; D002540:Cerebral Cortex / Q000002:abnormalities* / Q000473:pathology / Q000601:surgery; D004569:Electroencephalography / Q000379:methods*; D004833:Epilepsy, Temporal Lobe / Q000453:epidemiology / Q000473:pathology / Q000601:surgery; D005260:Female; D006624:Hippocampus / Q000473:pathology* / Q000601:surgery; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D012189:Retrospective Studies; D012598:Sclerosis / Q000473:pathology*; D018709:Statistics, Nonparametric