Abstracts

Rationale: Depression and anxiety are among the most common co-morbidities in temporal lobe epilepsy, often associated with a decrease in quality of life. In a previous study from our laboratory, we found a relationship between the amount of right hippocampal atrophy and the severity of depression and anxiety scores in patients with left temporal lobe epilepsy and left hippocampal atrophy. This study aims to expand on those results and investigate cortical changes, outside of the hippocampus, that are associated with anxiety and depression in this population.Methods: 10 patients (5 females) with a mean age of 36.6 ± 7.4 years were included in this study. All patients suffered from pharmaco-resistant left temporal lobe epilepsy. Each patient underwent volumetric measurement of bilateral hippocampal formations as part of their presurgical evaluation. Hippocampal volumes were derived by manually tracing consecutive coronal slices aligned perpendicular to the long axis of the hippocampus. In addition, cortical thickness measurements were derived using the FreeSurfer software (freely available for download online http://surfer.nmr.mgh.harvard.edu). Every patient completed the Minnesota Multiphasic Personality Inventory - Second Edition (MMPI-II). Correlations were carried out between normalized hippocampal volumes along with cortical thickness and depression and anxiety scores from the MMPI-II scales in patients with left hippocampal atrophy.Results: As reported in our previous study there was a significant correlation between the amount of right hippocampal atrophy and the severity of anxiety scores in patients with left hippocampal atrophy (r = -0.74, p = 0.015). In addition, there were positive statistically significant correlations between the severity of depression and cortical thickness of the right superior frontal (r = 0.91, p > 0.001), orbital frontal (r = 0.88, p > 0.001), inferior temporal (r = 0.86, p = 0.002) and anterior cingulate cortex as well as left anterior cingulate (r = 0.82, p = 0.003), posterior cingulate (r = 0.83, p = 0.003), opercular (r = 0.84, p = 0.003) and triangularis cortices (r = 0.79, p = 0.006). Finally, there were positive significant correlations between the severity of anxiety and cortical thickness of the left lateral occipital (r = 0.89, p > 0.001), lingual (r = 0.88, p > 0.001), superior parietal (r = 0.89, p > 0.001) and fusiform cortices (r = 0.76, p = 0.01) as well as right supramarginal (r = 0.76, p = 0.01) and post central gyri (r = 0.75, p > 0.001).Conclusions: These findings suggest that, in addition to a smaller right hippocampus, multiple areas of increased cortical thickness are associated with worse anxiety and depression symptoms in patients with left hippocampal atrophy and left onset of temporal lobe seizures. These findings support the notion that a larger network of brain areas are involved in those with depression and anxiety and may help in the understanding and treatment of patients who suffer from these comorbidites with temporal lobe epilepsy.