[Neuronet restructuring in focal and generalized epilepsy according to resting state fMRI]

[Structural brain changes in patients with temporal lobe epilepsy and comorbid depression]

OBJECTIVE

To assess the morphological features of the brain structures in patients with temporal lobe epilepsy and comorbid depression.

MATERIAL AND METHODS

From 1 January 2017 to 31 December 2020, we studied 80 patients with temporal lobe epilepsy (aged 18-60 years, 38 of whom had comorbid depression) and 48 healthy subjects of comparable age. Magnetic resonance imaging (MRI) of the brain was performed using the epilepsy protocol in a scanner with a magnetic field strength of 1.5 T. Focal temporal lobe epilepsy was diagnosed by neurologists (epileptologists) specialising in epilepsy according to the International League Against Epilepsy (ILAE) classification of epilepsy. Psychiatrists assessed the presence and severity of depressive disorders by clinical interview and by participants' scores on the Beck Depression Inventory (BDI-II). MRI data were processed using FreeSurfer 6.0 software to determine volumes of subcortical structures and thicknesses of cortical structures. At the group level, analysis of covariance with Holm-Bonferroni correction was used as the statistical method.

RESULTS

Morphometric analysis revealed a significant decrease in the volume of the thalamus bilaterally and the brain stem and an increase in the volume of the choroid plexus in the left hemisphere, as well as a significant decrease in the thickness of the entorhinal cortex, temporal pole and isthmus of the cingulate gyrus in the left hemisphere and middle temporal gyrus and inferior temporal gyrus in the right hemisphere in patients with epilepsy compared to healthy controls. No association was found between the presence of depression and significant structural changes on MRI.

CONCLUSION

The data obtained suggest an effect of temporal lobe epilepsy, but not comorbid depression, on the morphology of brain structures.

[Patterns of brain functional connectivity in frontal and temporal lobe epilepsies]

AIM

To examine alterations of functional connectivity (FC) of the brain in patients with frontal and temporal lobe epilepsies.

MATERIAL AND METHODS

Forty-three patients, aged 18-55 years, including 32 with temporal lobe epilepsy (TLE) and 11 with frontal lobe epilepsy (FLE), and 32 age/gender-matched healthy controls (HC) underwent structural and functional MRI on 1,5 T scanner. Imaging data were further analysed for functional connectivity characteristics by seed-based and ICA analyses.

RESULTS

Most prominent in the TLE group, was a decrease in FC of insula and peri-insular cortical regions compared to HC. These alterations of FC in left-side TLE were significant on the left. An increase of FC between dorsal part of attention resting network and regions of temporal and parietal cortices characterized right-side TLE. In addition, TLE group had decreased FC between anterior cingulate and basal ganglia. All the significant alterations of FC in FLE related to increased FC in patients compared to HC. FC of temporal regions was altered to a greater extent.

CONCLUSION

Localization and lateralization of seizure focus determines the alterations of brain FC in patients with focal epilepsy.