Abstracts

Rationale: Temporal lobe epilepsy (TLE) and hippocampal atrophy are associated with higher rates of depression (Quiske A. Depression in patients with temporal lobe epilepsy is related to mesial temporal sclerosis. Epilepsy Res 2000 39(2): 121-125). Studies show that rates of suicide in epilepsy, consistently higher than the general population, are even greater among patients who experience TLE (a rate of 25 times higher than the general population) (Barraclough B., Suicide and epilepsy. In Epilepsy and Psychiatry, pp. 72-76, 1981). We hypothesize that patients who have reduced hippocampal volume on MRI will show less mood improvement in the peri-ictal period and will report more interictal depressive symptoms than those patients who do not have smaller hippocampal volume. The hippocampus is an important component of the limbic system, the regulation of emotions, in addition to its role as an arbiter of long term memory. It plays a critical role in the regulation of learning, memory, motivation and emotion. Notably, the hippocampus also has connections with the activity of other cortical areas including the pre-frontal cortex, the anterior thalamic nuclei, the amygdala, basal ganglia, and the hypothalamus, which are all also involved in mood regulation. Studies have reported that stress toxicity and lack of neurotrophic factors result in structural abnormalities of the hippocampus. Reduced hippocampal volumes could lead to affective symptoms related to mood disorder, and thus, those patients with smaller hippocampal volumes may not experience mood improvement after a seizure to the same extent as those patients with normal volumes (Frodl T, Schaub A, Banac S., et al. Reduced hippocampal volume correlates with executive dysfunctioning in major depression. J Psychiatry Neurosci 2006;31(5):316-325). Specific Aim 1: To characterize changes in mood in epilepsy patients during the peri-ictal period Hypothesis: Patients with epilepsy are likely to have improvements in mood after seizures Specific Aim 2: To determine whether localization of seizure onset is related to differences in mood scores Hypothesis: Patients with temporal lobe epilepsy are more likely to have improvements in mood after seizures Specific Aim 3: To determine if hippocampal size is related to depressed mood in patients with epilepsy Hypothesis: Patients with epilepsy and hippocampal volume loss are more likely to have depressed mood and are less likely to have improvements in mood after seizures Methods: Patients admitted to the Epilepsy Monitoring Unit (EMU) for video EEG monitoring completed Beck Depression and Beck Anxiety questionnaires upon enrollment and at 4, 12, 24 hours and 2 weeks after a seizure captured in the EMU. Seizure type was classified by EEG analysis by qualified epileptologists. Data from MRI scans performed for clinical care were processed through Freesurfer, an automatic segmentation computer program, to measure hippocampal volumes. Results: Patients experienced improvements in depressed mood at 4 hours (p=0.0086, t=3.052) and in anxiety at 12 hours (p=0.0186, t=2.866) following a seizure. In patients with TLE, hippocampal volume loss is associated with higher levels of anxiety (R2=0.93, n=4), and with less of an improvement in mood following seizures compared to patients with larger hippocampi. Conclusions: Preliminary results show improvements in depression and anxiety symptoms in hours following a seizure. MRI scans reveal a relationship between hippocampal volume and degree of mood improvement. These data are preliminary and further enrollment is occurring to further power the study. Funding: Barnett Award - University of Maryland School of Medicine