To evaluate the impact of EEG–MRI concordance & discordance on post-surgical seizure outcomes in pediatric & adults with focal drug resistant epilepsy (DRE)

This ambispective study included DRE from a tertiary hospital in India (2014–2024). DRE with VEEG ictal onsets with a single focal MRI lesion were included. MRI-negative cases, >2 lesions, or lobar expansion were excluded. Cases were divided into concordant (Arm A) and discordant (Arm B) groups, with surgical outcomes evaluated using Engel’s scale & ILAE outcome classification

Of 3891 DRE cases screened, 852 met criteria (754 retrospective, 98 prospective). The cohort included 54.93% adults (≥18 years) and 45.07% pediatric cases (<18 years), with a male predominance (69.13%). VEEG-MRI concordance was seen in 64.2%, discordance in 35.8% (moderate agreement, kappa = 0.527, p<0.05). Among 155 operated cases, seizure freedom (Engel I & ILAE class 1&2) was significantly higher in concordant cases (80.61%)vs discordant (47.37%) (p<0.05).In pediatric cases, seizure freedom was 75.00%(concordant)vs 37.93%(discordant),p=0.003,and in adults, 83.87%vs 57.14%,p=0.006.Temporal lobe focus showed highest seizure freedom(87.84%concordant vs 51.72%discordant, p=0.0001).Seizure control(Engel 1&2) was comparable for 94.8%(concordant) vs 87.72%(discordant)(p>0.05). Resective procedures showed significantly higher seizure freedom in Concordant group(83.72%vs. 56.25%,p=0.002),while non-resective procedures had comparable outcomes(58.33%vs.36.00%,p value= 0.199).

Concordance was highest in temporal lobe cases(76.66%), while discordance was highest in parietal (73.33%)and occipital(90.48%) cases. Concordant cases had significantly higher post-op seizure freedom. In contrast, seizure control was comparable in both groups, and no significant difference was found between pediatric and adult outcomes in operated discordant and concordant cases