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

Abstract

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 (11), 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 < 0.90 in 16, 0.90-0.94 in 14 and > or = 0.95 in 17 patients. EEGs were normal in only five patients. Alpha rhythm was preserved in 78 patients, including one patient with bilateral posterior macrogyria. Localized polymorphic slow activity was present in 43 patients. Five of 68 patients with focal/unilateral CD had only bilateral independent/synchronous spiking and 14 out of 32 with diffuse/bilateral CD only focal/unilateral spiking. In 60 patients with nondiffuse CD or with abnormal gyration or DNT, the epileptiform abnormalities were less extensive than coextensive with the lesion in 28, more extensive than and overlapped the lesion in 18 and remote from the lesion in five; nine patients did not have epileptiform abnormalities. There was poor correlation between the epileptic syndromes and EEG abnormalities and the location/extent of CD as defined by MRI and pathology.(ABSTRACT TRUNCATED AT 400 WORDS)

Correlation of EEG, neuroimaging and histopathology in an epilepsy patient with diffuse cortical dysplasia

“…This widespread cortical malformation corresponded well to a subtype, macrogyria/polymicrogyria with neuronal cleft, in the classification of Raymond et al [16]. However, we could not found the previous report about the reverse of the gray and white matter.…”

“…Clinical features of them were also different between the patients. Some classifications of cortical dysplasia were proposed as based on the findings of neuroimaging and/or histological characteristics [1,2,3,6,11,16]. However, it may be difficult to classify into one of subtypes in these patients.…”

“…However, it may be difficult to classify into one of subtypes in these patients. Etiologically, it has been known that cortical dysplasia is caused by disorder of neuronal proliferation and/or migration [3,4,6,10,14,15,17], whereas polymicrogyria can occur from cortical damage such as cerebral ischemia in early postnatal period [16]. As microdysgenesis, which is identified only as microscopically abnormal structures of cortex, can not find in MR images, it seems to be better that cortical dysplasia is classified histopathologically.…”

Effect of sleep on interictal spikes and distribution of sleep spindles on electrocorticography in children with focal epilepsy

“…On MRI, six children showed the evidence of focal cortical dysplasia (Raymond et al, 1995); four children had multiple cortical tubers; three children had a brain tumor; one child each had a solitary tuber and focal ulegyria. In the remaining two children, MRI was normal but FDG PET scan showed cortical regions with glucose hypometabolism in the presumed epileptic hemisphere.…”

Advances in neuroimaging in patients with epilepsy

“…Malformations of cortical development constitute 10-50% of pediatric epilepsy cases being evaluated for surgery and 4-25% of adult cases of intractable epilepsy. 103,136 Wolf and Wiestler 135 reported a frequency of 18% for cortical dysplasia in surgical specimens obtained in a series of 216 adult patients with intractable epilepsy. In contrast, in pediatric patients with refractory epilepsy who had undergone resection, Jay et al 54 reported a 30% frequency of FCD, whereas Farrell et al 36 reported a 39% frequency of FCD.…”