Abstracts

Rationale: Bilateral hippocampal atrophy has been demonstrated in patients with primary major depressive and bipolar disorders. Given the high prevalence of mood disorders in patients with temporal lobe epilepsy (TLE) we hypothesized that: (1) the presence of hippocampal atrophy would be associated with more severe symptoms of depression and (2) the existence of a significant correlation between the severity of depression symptoms and magnitude of hippocampal atrophy. The purpose of this study was to test these hypotheses and to establish whether hippocampal atrophy could be associated with other psychiatric symptoms.Methods: This study included 53 consecutive patients (25 females) with a mean age of 37±11.3 years and a mean duration of the seizure disorder of 19.1±12.4 years. All patients suffered from pharmaco-resistant TLE and underwent volumetric measurement of hippocampal formations as part of their presurgical evaluation. T1 weighted MRI scans were acquired using a 3-D SPGR pulse sequence. Hippocampal volumes were derived by manually tracing consecutive coronal slices aligned perpendicular to the long axis of the hippocampus. Every patient completed the Minnesota Multiphasic Personality Inventory - Second Edition (MMPI-II). Patients were considered to be symptomatic in any of the 10 MMPI clinical scales if they had a T score of > 65. The number of symptomatic scales was calculated for each patient. Statistical analyses: (1) Non-parametric statistics were used to identify any association between the presence of hippocampal atrophy and scales 2 (depression) and 7 (anxiety), or any other scale(s). T-test was used to compare the normalized hippocampal volumes between patients symptomatic on the depression and anxiety scales. Correlations were carried out between the scores of normalized hippocampal volumes and: (i) the depression (ii) anxiety scales and (iii) total number of symptomatic MMPI-II scales. Results: Among the 53 patients, 25 had hippocampal atrophy, 11 on the left, 12 on the right and two bilaterally. Thirty patients (56.6%) were symptomatic on the depression scale, 18 (34%) on the anxiety scale and 16 (30%) on both. There was a significant correlation between the left and right hippocampal volumes (r = 0.347, p = 0.024). There was a significant association between the presence of hippocampal atrophy and being symptomatic on the anxiety scale (p = 0.019, Fisher Exact, 2 tailed), but not on the depression scale. By the same token there was a statistical trend between the magnitude of left hippocampal atrophy and the severity in the score (severity) of the anxiety scale (p = 0.064, F = 3.64). In addition, there was an inverse correlation between the number of symptomatic MMPI-II scales and the left but not right hippocampal volumes. These findings were independent of the side of seizure focus.Conclusions: These data suggest a possible relationship between hippocampal atrophy and anxiety, but not depression. These findings suggest that hippocampal atrophy per-se is not associated with a mood disorder in TLE and other pathogenic mechanisms may be operant in the development of depressive symptoms.