1438 – Default Mode Network In Left-sided Temporal Lobe Epilepsy Patients With And Without Comorbid Affective Disorders

Abstract

Affective disorders are common in patients with temporal lobe epilepsy, especially in cases of left-sided epileptic focus localization (lsTLE).

Aim

To characterize connectivity patterns of brain default mode network (DMN) in lsTLE patients with and without anxiety and depressive disorders.

Subjects and methods

28 lsTLE patients, divided into two groups: patients with (“affective” group) and without anxiety- depressive symptoms. Beck Depression Inventory (BDI), Hospital Anxiety Depressive Scale (HADS), Hamilton Anxiety Scale (HAM-A) and Montgomery-Asberg Depressive Rating Scale (MADRS) were used to assess affective symptoms. All subjects underwent 9-min resting-state fMRI scanning session. Independent component analysis (ICA) was used to isolate DMN. The resulted maps were compared in groups using two-sample t-test. The results were considered as statistically significant according to threshold of p < 0.005 with a 10-voxel extent that has recently been shown to produce an optimal balance between Types I and II error rates in fMRI studies (Lieberman, 2009). The data were processed and analyzed using SPM8 and “GIFT” toolbox for ICA “GIFT”.

Results

Mild depression and moderate-severe anxiety levels were observed in the "affective" group. Significantly increased functional connectivity was found in “affective” group in the right cerebellum (culmen), right gyrus fusiformis, dorsolateral prefrontal and midcingulate area, and in the left insula.

Conclusions

We found that brain DMN is altered by affective disorders associated with lsTLE. The observed regional pattern of difference can reflect the impaired levels of self-control often present in lsTLE patients with affective symptoms