Abstracts

Rationale: To search for areas with reduced gray matter volume (GMV) in patients with MTLE with and without dysthymic disorder (DD), compared to normal controls. Methods: We included 52 adults with MTLE (34 women, 38.38±8.6 years) and 105 healthy controls (69 women, 35±8.7 years). All patients were interviewed for the diagnosis of DD, answered the Beck Depression Inventory and underwent high-resolution MRI scan. Patients were separated in two groups: Group 1: MTLE with DD (26 patients); Group 2: MTLE without DD (26 patients). Images with right hippocampal atrophy were left-right flipped to allow simultaneous analysis. We performed VBM analysis on SPM5 and MATLAB7, comparing groups of patients with control group using T-test. The statistical analysis for all comparisons was performed with grand mean scaling, proportional threshold masking and implicit masking. We defined the contrast searching for areas of reduced GMV. The results were corrected for multiple comparisons using a false discovery rate of 5% with an extended threshold looking for clusters with at least of 32 contiguous voxels. We converted the stereotaxic coordinates provided in the SPM output to anatomical names with the use of the MNI Space Utility and Talairach Space utility. We used T-test, Fisher’s exact test and Pearson correlation coefficient on SYSTAT 9. Results: Group 1 and 2 were homogeneous in terms of age, gender, side of epileptic focus, epilepsy duration, epilepsy onset, and frequency of seizures. The BDI scores of Group 1 were not associated to age, epilepsy onset, epilepsy duration, frequency of seizures, gender, education, marital status, employment, seizures type, number of AEDs and laterality of hippocampal sclerosis. Group 1 showed GMV loss in the left parahippocampal gyrus (p<0.001), left hippocampus (p<0.001), bilateral frontal gyrus (p=0.003), right inferior and middle temporal gyrus (p=0.035), bilateral superior temporal gyrus (p=0.04), bilateral inferior parietal gyrus (p=0.09), left superior parietal gyrus (p=0.018), bilateral precuneus (p=0.095), right insula (p=0.017), and left precentral gyrus (p=0.08), caudate body (p=0.03), fusiform gyrus (p=0.011) and cingulate gyrus (p=0.033) (Figure 1). Group 2 showed GMV loss in the left parahippocampal gyrus (p=0.005), hippocampus (p=0.005), caudate nucleus (p=0.04) and thalamus (p=0.028), and right frontal gyrus (p=0.008) (Figure 2). Conclusions: Neuroimaging changes in patients with MTLE, undetected by visual analyses, seem to be magnified in the presence of chronic DD. The evidence of GMV loss in patients with MTLE and DD calls our attention to the importance of timely recognition and treatment of depression in patients with MTLE and also to the bidirectional relationship between the two disorders and their frequent co-occurrence.