Abstracts

Rationale: Research on antiepileptic drug (AED) efficacy by lobe is lacking in literature. Understanding which AED is more effective to treat seizures originating from a specific lobe may help better achieve rational drug-therapy. In this retrospective study, we compared the effectiveness of 13 AEDs within lobes for patients with localization-related epilepsy (LRE).Methods: Adult outpatients (>16 years) with LRE were selected from the Columbia-Yale AED Database if they had LRE with physician-confirmed seizure focus and attempted >2 unique drug regimens for >6 continuous months. Efficacy was gauged by >6 months of continuous seizure freedom (SF6). We investigated 124 non-AED clinical factors associated with SF6. We then performed two logistic regressions: 1) Comparison of the SF6 rate of one lobe of a given AED to the average SF6 of the other lobes of that same AED, and 2) pairwise lobe-by-lobe comparison of the SF6 rates with a given AED. We censored all data following any surgical resection. We separately analyzed temporal lobe epilepsy (TLE) patients with and without mesial temporal sclerosis (MTS), yielding 6 lobe categories: Frontal (FLE), TLE with MTS, TLE without MTS, occipital (OLE), parietal (PLE), and multiple lobe epilepsy (MLE). AEDs used by <75 patients were excluded, yielding the 13 AEDs under investigation. We controlled for severity by dichotomizing into failed number of AEDs of >2 (intractable) vs <2 (milder severity), and calculated the average SF6 dose and drug level of each AED. The P-value for all analyses was P<0.05.Results: 1,886 patients (863 male) were included. Median age was 42 ± 16 years. Milder severity was the only significant non-AED predictor of SF6 (P<0.001, OR = 2.793). Lobe-by-lobe analyses revealed that: ● Clobazam (CLB) had its highest SF6 rate in OLE (71.4%), significantly greater than its aggregate SF6 rate in all other lobes (40.4%, P = 0.023, OR = 3.964), specifically greater than in FLE (39.4%, P = 0.036, OR = 3.846) and TLE without MTS (36.3%, P = 0.015, OR = 4.479). ● Lamotrigine (LTG) had its lowest SF6 rate in MLE (38.0%), significantly lower than its aggregate (56.3%, P = 0.003, OR = 0.483), lower than in FLE (54.0%, P = 0.026, OR = 0.545), TLE with MTS (54.0%, P = 0.022, OR = 0.511), TLE without MTS (60.0%, P = 0.002, OR = 0.457), and OLE (68.4%, P = 0.035, OR = 0.314). ● Oxcarbazepine (OXC) had its highest SF6 rate in FLE (46.7%), significantly greater than its aggregate (31.5%, P = 0.013, OR = 2.352), greater than in TLE with MTS (19.2%, P = 0.028, OR = 3.651) and TLE without MTS (28.3%, P = 0.014, OR = 2.437). ● Zonisamide (ZNS) had its lowest SF6 rate in FLE (18.2%), significantly lower than its aggregate (30.6%, P = 0.029, OR = 0.438), lower than in TLE without MTS (32.9%, P = 0.045, OR = 0.454), OLE (66.7%, P = 0.019, OR = 0.111), and PLE (53.3%, P = 0.009, OR = 0.194).Conclusions: CLB and OXC were more efficacious in achieving SF6 in OLE and FLE, respectively, while LTG and ZNS demonstrated lower efficacy in MLE and FLE, respectively, compared to other lobes. CLB appeared to be particularly efficacious in OLE, warranting further research.