Abstracts

Rationale: Research on patients with major depressive disorder has demonstrated that elevated cortisol levels are associated with memory impairment and hippocampal atrophy in these patients. Temporal lobe epilepsy (TLE) is often associated with depression, memory dysfunction, and hippocampal atrophy. However, the relationships among these factors within TLE patients have not been well-delineated. This study was designed to prospectively examine the relationships among late night salivary cortisol (NSC) levels (an index of hypercortisolism) and depressive symptoms, memory performance, and hippocampal volumes in patients with medically intractable TLE. Methods: This prospective study included twenty-four adults with well-characterized medically refractory TLE (right=11; left=12; bitemporal=1), as defined by concordant seizure semiology as well as interictal and ictal EEG recordings. Mean age was 39.71 (SD=11.56) and education was 14.04 years. Mean age of seizure onset was 26.33 years (SD=12.58), and duration of epilepsy was 13.29 years (SD = 9.92). All patients provided samples to measure NSC and completed measures of mood, anxiety, and memory (objective and subjective). MRI-based volumetric analyses of the hippocampi were also conducted. Results: Bivariate correlations were calculated to examine the strength of the relationship between cortisol level and mood, anxiety, memory, and hippocampal volume. Unexpectedly, cortisol levels were not related to symptoms of depression or anxiety, subjective memory ratings, objective memory performance, or hippocampal volume (range r = -.06 to -.32). Although no significant relationships were observed between cortisol and the variables of interest in this study, there were several significant relationships among other study variables. Objective memory performance on the Rey Auditory Verbal Learning Test (RAVLT) was related to both left (r = .45) and right hippocampal volumes (r = .48). Subjective memory complaints were not related to objective memory performance, but were strongly correlated with symptoms of depression [Personality Assessment Inventory (PAI) Depression Subscale r = -.52; Center for Epidemiological Studies - Depression Scale (CES-D) r = -.46] and trait anxiety as assessed by the State Trait Anxiety Index (r = -.44). Additional regression analyses revealed that depression scores, as assessed by the CES-D and the PAI, predicted subjective memory ratings on some measures (p < .05). There was also a trend for the PAI Depression subscale to predict objective memory performance on the RAVLT (p = .07). Conclusions: Results suggest that NSC is not related to symptoms of depression or anxiety or to functional and structural integrity of the mesial temporal lobe in patients with intractable TLE. However, consistent with existing literature, objective memory was related to hippocampal volume, and subjective memory was related to mood and anxiety symptoms.