Abstracts

RATIONALE: Depression is a common clinical finding in patients with intractable focal epilepsy. Recent investigations indicate that these patients, in addition to hippocampal sclerosis (HS) have more generalised cerebral atrophy. Research has found that depressive symptomatology is associated with generalised atrophy in older patients. Numerous hypotheses have been proposed to explain the high prevalence of depression in epilepsy. The current investigation examines three groups; a focal TLE patient group with volumetrically defined HS, TLE patients without HS and controls. The contribution of cerebral and hippocampal volumes, memory abilities and the number of years of habitual epilepsy to depression is examined.
METHODS: 34 TLE patients, 25 with HS and 9 with no HS, with a history of complex partial seizures were examined. Volumetric MRI studies were performed and whole brain volumes (WBV) and total hippocampal volumes (THV) derived. A control group (N=97)was used to compare the extent of atrophy. The Wechsler Memory Scale - Revised (WMS-R) was used to determine memory abilities and the Beck Depression Inventory (BDI) provided a measure of affective status. Correlational analysis was performed between BDI scores and standardised formal psychiatric interview conclusions. To determine differences in WBV and THV between TLE patients with HS, TLE patients with no HS and controls, a 2-way MANCOVA, with age as a covariate was performed. Hierarchical linear regression analysis was used to predict BDI scores from WBV.
RESULTS: There was a high correlation between psychiatric interview conclusions and patient scores on the BDI. There was no significant difference between the two patient groups on WBV. However, both patient groups had significantly reduced WBV in comparison to controls. TLE patients with HS had significantly reduced THV in comparison to TLE patients with no HS and controls. Hierarchical regression indicated that WBV was the only significant predictor of BDI scores, with a significant inverse relationship. Neither THV, memory abilities, nor the number of years of habitual epilepsy were significant predictors of BDI scores.
CONCLUSIONS: These findings support previous research that depression is related to generalised brain atrophy. Further work is required to establish the relationship of depresion to patient perceived quality of life, the effects of pharmacotherapy and other variables related to seizure activity, such as the severity of seizures. Given the high incidence of mood changes postoperatively in this group, such preoperative measures may provide useful information regarding the multifaceted nature of depression and its[scquote] aetiology.