Medial temporal lobe atrophy in patients with refractory temporal lobe epilepsy

Neuroimaging Laboratory, Department of Neurology, State University of Campinas, Brazil.
Journal of Neurology Neurosurgery & Psychiatry (Impact Factor: 5.58). 12/2003; 74(12):1627-30. DOI: 10.1136/jnnp.74.12.1627
Source: PubMed

ABSTRACT The objective of this study was to assess the volumes of medial temporal lobe structures using high resolution magnetic resonance images from patients with chronic refractory medial temporal lobe epilepsy (MTLE).
We studied 30 healthy subjects, and 25 patients with drug refractory MTLE and unilateral hippocampal atrophy (HA). We used T1 magnetic resonance images with 1 mm isotropic voxels, and applied a field non-homogeneity correction and a linear stereotaxic transformation into a standard space. The structures of interest are the entorhinal cortex, perirhinal cortex, parahippocampal cortex, temporopolar cortex, hippocampus, and amygdala. Structures were identified by visual examination of the coronal, sagittal, and axial planes. The threshold of statistical significance was set to p<0.05.
Patients with right and left MTLE showed a reduction in volume of the entorhinal (p<0.001) and perirhinal (p<0.01) cortices ipsilateral to the HA, compared with normal controls. Patients with right MTLE exhibited a significant asymmetry of all studied structures; the right hemisphere structures had smaller volume than their left side counterparts. We did not observe linear correlations between the volumes of different structures of the medial temporal lobe in patients with MTLE.
Patients with refractory MTLE have damage in the temporal lobe that extends beyond the hippocampus, and affects the regions with close anatomical and functional connections to the hippocampus.

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    ABSTRACT: OBJECTIVE: To investigate the variation of thalamic and hippocampal volume in patients with mesial temporal lobe epilepsy (MTLE) refractory or responsive to drug therapy. METHODS: We analyzed 26 patients with MTLE responsive to drug therapy, 25 refractory and 23 controls through the manual delineation of anatomic limits of the hippocampus and thalamus, in sequential sections of MR images. The DISPLAY software was used. Statistical analysis was performed using the program Systat 9. RESULTS: There were statistically significant differences between controls and patients groups for thalamic volumes ipsilateral to epileptogenic focus (p=0.00004). There was no statistical difference between the 3 groups for the volumes of the thalamus contralateral to the epileptogenic focus. There was significant correlation between ipsilateral hippocampus and thalamus ipsilateral to epileptogenic focus (r=0.35, p=0.004). The older the age, the lower the ipsilateral thalamic volume (p=0.002 and r=-0.37). CONCLUSION: The data showed that hippocampal atrophy is also present in patients with TLE and good seizure control. The atrophy of thalamus was correlated with the age of patients, which may also indicate that other factors besides the seizure frequency influences the degree of damage of this structure.
    Journal of Epilepsy and Clinical Neurophysiology 12/2011; 18(2):41-44. DOI:10.1590/S1676-26492012000200004
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    ABSTRACT: The hippocampus plays an important role in the genesis of mesial temporal lobe epilepsy, and the entorhinal cortex (EC) may affect the hippocampal network activity because of the heavy interconnection between them. However, the mechanism by which the EC affects the discharge patterns and the transmission mode of epileptiform discharges within the hippocampus needs further study. Here, multielectrode recording techniques were used to study the spatiotemporal characteristics of epileptiform discharges in adult mouse hippocampal slices and combined EC-hippocampal slices and determine whether and how the EC affects the hippocampal neuron discharge patterns. The results showed that low-Mg(2+) artificial cerebrospinal fluid induced interictal discharges in hippocampal slices, whereas, in combined EC-hippocampal slices the discharge pattern was alternated between interictal and ictal discharges, and ictal discharges initiated in the EC and propagated to the hippocampus. The pharmacological effect of the antiepileptic drug valproate (VPA) was tested. VPA reversibly suppressed the frequency of interictal discharges but did not change the initiation site and propagation speed, and it completely blocked ictal discharges. Our results suggested that EC was necessary for the hippocampal ictal discharges, and ictal discharges were more sensitive than interictal discharges in response to VPA.
    Neural Plasticity 03/2014; 2014:205912. DOI:10.1155/2014/205912 · 3.60 Impact Factor
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    ABSTRACT: Temporal lobe epilepsy (TLE) and idiopathic generalized epilepsy (IGE) patients have each been associated with extensive brain atrophy findings, yet to date there are no reports of head to head comparison of both patient groups. Our aim was to assess and compare between tissue-specific and structural brain atrophy findings in TLE to IGE patients and to healthy controls (HC).
    BMC Neurology 06/2014; 14(1):131. DOI:10.1186/1471-2377-14-131 · 2.49 Impact Factor

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