Abnormalities of gyration, heterotopias, tuberous sclerosis, focal cortical dysplasia, microdysgenesis, dysembryoplastic neuroepithelial tumour and dysgenesis of the archicortex in epilepsy: Clinical, EEG and neuroimaging features in 100 adult patients

Cerebral cortical dysgenesis (CD) is a heterogeneous disorder of cortical development and organization commonly associated with epilepsy, with a variety of subtypes. We reviewed the clinical, EEG and neuroimaging features in 100 adult patients with CD. There were 39 men and 61 women with a median age of 27 years (range 15–63 years). All patients were referred because of medically refractory epilepsy. Median age at seizure onset was 10 years (range 3 weeks to 39 years); in 30 patients, onset was in adulthood. The epilepsy was classified as generalized in 16 patients and localization-related in 84. Of the latter, the epileptic syndromes in decreasing frequency were frontal (32%), temporal (31%), parietal (14%) and occipital (7%). Only 15% of patients had a history of status epilepticus. Prenatal/ perinatal problems were reported in 32 patients but these were severe in only four: exposure to drugs (three) and infection (one) during the first trimester. Delayed developmental milestones were seen in 10%, mental retardation in 9%, additional congenital abnormalities in 4% and neurological deficits in 14% of patients. Diagnosis of CD was based on neuroimaging in 70, pathology in four and both methods in the remaining 26. The following subcategories were identified: agyria/diffuse macrogyria (four patients), focal macrogyria (16), focal polymicrogyria (one), focal macrogyria/polymicrogyria associated with a cleft (II), 20 months; range 2 months to 14 years). Eleven of the 21 patients with DNT and four out of 14 patients with other forms of CD were completely seizure-free (one with focal cortical dysplasia, two with hippocampal sclerosis associated with CD and one with microdysgenesis). Of the patients with DNT, eight out of 10 were seizure-free after a lobectomy as compared with three out of 11 after a lesionectomy (P < 0.05). Of 46 age-matched healthy volunteers (median age 28 years) minor gyral abnormalities (seven), subependymal grey matter heterotopia (20), bilateral subcortical laminar grey matter heterotopia (eight), tuberous sclerosis (five), focal cortical dysplasia/microdysgenesis (seven) and dysembryoplastic neuroepithelial tumours (DNT) (21). Sixty-eight percent of patients had normal CT and 19 out of 36 patients had normal previous conventional MRI. MRI-based hippocampal volume measurements in 47 patients revealed ratios (smaller: larger hippocampus) of