Abstracts

Rationale: Persons with epilepsy are at risk for depression and commonly related symptoms such as anxiety and irritability. Those with temporal lobe epilepsy may be at highest risk due to limbic regulation of affect and mood. Baseline affective status data were collected from persons with medically refractory, well localized partial-onset epilepsy who participated in a pivotal trial of the RNS System (NeuroPace, Inc.). An analysis was conducted to assess whether affective symptoms are more prevalent in persons with seizure onsets in the temporal lobe than those with onsets exclusively extratemporal.Methods: Subjects participating in the trial were 18-70 years old, had ? 3 disabling partial seizures/month localized to one or two seizure foci, and had failed treatment with ? 2 AEDs. Active psychosis, major depression, or suicidal ideation in the preceding year excluded participation. A medical history, the Beck Depression Inventory (BDI-II), Center for Epidemiological Studies - Depression (CES-D), and Profile of Mood States (POMS, which includes symptoms of anxiety and irritability as well as depression) were collected. Summary scores for the baseline inventories were compared for subjects with any seizure onset in the temporal lobe and subjects with purely extratemporal seizure onset(s) using two-sample t-tests. A separate analysis was performed in subjects with and without verbal memory dysfunction, defined as a pre-implant score ? 5th percentile on age-based normative data for the Rey Auditory Verbal Learning Test (RAVLT, I-V Sum Across Trials).Results: Among the 189 subjects in the analysis, 78% had at least one seizure onset in the temporal lobe. Subjects with temporal lobe onsets were more depressed than subjects with purely extratemporal onsets according to the BDI-II (p=0.003) and CES-D (p=0.030), but not the POMS (Table 1). Of the six POMS factors, there was a statistically significant difference in Confusion-Bewilderment (p=0.027) only. Verbal memory dysfunction was present in 55% of the temporal and 47% of the extratemporal subjects. In subjects with memory deficits, there was no association between seizure onset zone and mood disturbances, whereas in subjects without memory deficits, summary scores on the BDI-II (p=0.03), CES-D (p=0.01), and POMS (p=0.03) were higher in the group with any temporal onsets.Conclusions: Baseline data reveal an association between depressive symptoms and temporal lobe epilepsy, particularly in the absence of verbal memory dysfunction. Symptoms associated with depression in epilepsy patients including anxiety and irritability affect persons with both extratemporal and temporal lobe epilepsy, suggesting a more diffuse neurobiological mechanism for ancillary symptoms than that of pure depression. Finally, results suggest that screening inventories for mood and depression in epilepsy are not interchangeable and must be carefully selected.