Subcortical epilepsy?

Departments of Medicine (R.A.B.B., S.J.V., M.J.C.) and Electrical and Electronic Engineering (R.A.B.B.), The University of Melbourne, Melbourne
Neurology (Impact Factor: 8.3). 05/2013; 80(20):1901-7. DOI: 10.1212/WNL.0b013e3182929f4f
Source: PubMed

ABSTRACT In the past, the cortex has for the most part been considered to be the site of seizure origin in the different forms of epilepsy. Findings from histopathologic, electrophysiologic, and brain imaging studies now provide ample evidence demonstrating that like normal cerebral function, epileptic seizures involve widespread network interactions between cortical and subcortical structures. These studies show that different forms of generalized and focal epileptiform discharges and seizures engage various subcortical structures in varying ways. This interaction has been the subject of many reviews and is not the focus of the current work. The aim of this review is to examine the evidence suggesting the possibility for some of the subcortical structures to initiate seizures independently and the clinical implications of this.

1 Bookmark
  • Neurology 01/2014; 82(4):373. DOI:10.1212/01.wnl.0000443818.22087.0d · 8.30 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Rats with brain dysplasia evoked by interruption of different stages of prenatal neurogenesis show characteristic variations in susceptibility to seizures depending on the neurochemical specificity of pharmacological agents used to evoke seizures. To verify a discrepancy between the data obtained using different pharmacological models, neurochemically neutral electroshocks were applied here. To produce brain dysplasia of different degrees, pregnant Wistar rats were exposed to a single 1.0Gy dose of gamma rays on gestation days 13, 15, 17 or 19. From the postnatal day 60, their male offspring (E13s, E15s, E17s and E19s, respectively) were subjected to 21 daily electrical stimulations to evoke seizures. Profiles of tonic and clonic reactivity to electrical stimulation significantly differed from those observed following pilocarpine or kainic acid administration. E17s showed minimal intensity of tonic but maximal of clonic responses. On the contrary, very high tonic and low clonic reactivity was observed in E13s and E15s. Periventricular nodular heterotopias (PNHs) were observed exclusively in E15s and E17s. Generally, the size of PNHs was correlated positively with susceptibility to tonic seizures but negatively with susceptibility to clonic seizures. Analogous correlations with the size of the neocortex were opposite. E13s and E19s had brains devoid PNHs but showed high tonic seizure susceptibility similar to that in E15s. It can therefore be concluded that PNHs modified the type of seizure reactivity from tonic to clonic, depending of their size, but the presence of PNHs was not necessary for the development of seizure susceptibility itself.
    Epilepsy research 10/2013; DOI:10.1016/j.eplepsyres.2013.10.010 · 2.48 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Objective: To determine the frequency of hyperintense cortical signal (HCS) on T1-weighted pre-contrast MRI in progressive multifocal leukoencephalopathy (PML) patients, its association with seizure risk and immune reconstitution inflammatory syndrome (IRIS), and its pathologic correlate.Methods: We reviewed clinical data including seizure history, presence of IRIS, and MRI scans from PML patients evaluated at our institution between 2003 and 2012. Cases that were diagnosed either by CSF JC Virus (JCV) PCR, brain biopsy or autopsy, and who had MRI images available were included in the analysis (n=49). We characterized pathologic findings in areas of the brain displaying HCS in two patients and compared them with isointense cortex in the same individuals.Results: Of 49 patients, 17 (34.7%) had seizures and 30 (61.2%) had HCS adjacent to subcortical PML lesions on MRI. Of the 17 PML patients with seizures, 15 (88.2%) had HCS compared to 15/32 (46.9%) patients without seizures (p= 0.006). HCS was associated with seizure development with a relative risk (RR) of 4.75 (95% confidence interval of 1.2 to 18.5; p=0.006). Of the 20 patients with IRIS, 16 (80.0%) had HCS compared to 14/29 (49.3%) of those without IRIS (p=0.04). On histological examination, HCS areas were associated with striking JCV-associated demyelination of cortical and sub-cortical U-fibers, significant macrophage infiltration and a pronounced reactive gliosis in the deep cortical layers.Interpretation: Seizures are a frequent complication in PML. HCS is associated with seizures as well as IRIS, and correlates histologically with JCV focal leukocortical encephalitis (JCV FLE). ANN NEUROL 2014. © 2014 American Neurological Association
    Annals of Neurology 03/2014; 75(5). DOI:10.1002/ana.24144 · 11.91 Impact Factor


Available from
Jun 5, 2014