Drug load and memory during intracarotid amobarbital procedure in epilepsy

Background: Anti-seizure medications (ASMs) have been related to poor cognitive function, but their relationship with intracarotid amobarbital procedure (IAP) results remains unclear. Aims of the Study: To elucidate whether the number and drug load of ASMs are associated with memory scores of the IAP and the neuropsychological assessment. Methods: Fifty-nine adult patients with drug-resistant epilepsy (mean age = 36.1, SD = 11.6) underwent bilateral IAP (with drawings and words as memory items) and a neuropsychological assessment to assess the risk of post-surgical memory decline. Total ASM drug load was calculated by summing the daily dose/defined daily dose ratio of every ASM of each patient. Pearson's correlations and hierarchical regressions were computed. Results: Total IAP memory score was associated with total ASM drug load (r = -0.30, p = 0.02) and seizure frequency (r = -0.25, p = 0.05). After controlling clinical variables, total ASM drug load explained 16% of the variance of total IAP memory score. This relationship was especially prominent in patients with left hemisphere focus (r = -0.33, p = 0.04). The number of current ASMs was not related to IAP memory score (r = -0.16, p = 0.24). The number or drug load of ASMs were not related to neuropsychological assessment results (for all, p > 0.07). Conclusions: Our findings suggest that total drug load can be a confounding variable in the IAP memory performance that could explain, at least in part, the reverse asymmetries reported in different studies.