Rationale: Epilepsy surgery is a successful treatment option for medically refractory epilepsy; however, there remains a concern regarding the neuropsychological decline following surgical interventions. Methods: We performed a retrospective analysis of neuropsychological evaluations of patients who underwent resective epilepsy surgery at UC Irvine Medical Center from 2017-2019. We investigated cognitive function in different domains, including in language, verbal memory, non-verbal memory, visuospatial skills, and executive function. We also evaluated for their mood by looking at their level of depression and anxiety. Post-surgical evaluations were compared to pre-surgical scores using Mann-Whitney U test and Fisher exact test. Results: Thirty-seven patients were included in the study. Of these, 17 patients had undergone left temporal lobectomy, 16 with right temporal lobectomy, two with right frontal lobectomy, and two with left frontal lobectomy. Full seizure cessation was achieved in 54% of patients, while 43% showed partial reduction in seizure frequency. After surgery, patients showed improvement in symptoms of depression (BDI 15.6 ± 9.4 vs 10.9 ± 10.9; p = 0.03) but not in anxiety (BAI 14.1 ± 10.6 vs12.5 ± 13.9; p = 0.25). This post-surgical improvement in depression was only seen in patients who had undergone right temporal lobectomy, but not after left temporal lobectomy. The level of depression did not correlate with change in their AEDs or level of seizure control post-operatively.
Prior to surgery, patients with left temporal onset seizures had a tendency to have impaired language function as compared to patients with right temporal onset seizures (76% vs 47%; p = 0.08). This relationship became statistically significant when left-handed patients were excluded in a post-hoc analysis (85% vs 36%; p = 0.03). Patients with right temporal onset seizures were more likely to have a baseline impairment of their non-verbal memory as compared to patients with left temporal onset seizures, but this was not statistically significant (80% vs 67%; p = 0.35). In right-handed patients, there was a trend towards worsening nonverbal memory post-surgically in patients who underwent right temporal lobectomy vs left temporal lobectomy (55% vs 25%; p = 0.09). The change in nonverbal memory did not correlate with post-op seizure control (p = 0.67), change in AED (p = 0.62), or change in the level of depression (p = 0.64) or anxiety (p = 0.99).
Conclusions: Epilepsy surgery is an effective treatment for patients with intractable epilepsy. Patients show improvement in depression post-operatively, but not in anxiety. In line with prior literature, patients with left temporal onset seizures were more likely to have a baseline impairment in their language function, but this did not change post-operatively. The nonverbal memory was affected in right temporal lobe seizure patients, which further worsened after a right temporal lobectomy. This post-operative change in nonverbal memory did not correlate with post-op seizure control. Larger study is underway to validate this data. Funding: Please list any funding that was received in support of this abstract.: N/A
