Distance to the clinical SOZ explains early ictal recruitment outside the SOZ in 29 HUP SEEG patients

We asked whether interictal abnormalities in bipolar SEEG pairs outside the clinically labeled seizure-onset zone (SOZ) predict early ictal recruitment after accounting for distance to the SOZ. We joined archived interictal features from a 120-s clip, archived ictal features averaged over up to three seizures, and fsaverage electrode coordinates for OpenNeuro ds004100. In 29 patients (2,636 non-SOZ pairs), the 30–100 Hz ictal power rise and interictal spike rate both decreased with distance to the SOZ (mean rho −0.20, p = 0.003; and −0.19, p = 0.0004). After controlling for log distance and whether a pair shared a shaft with an SOZ pair, interictal 80–150 Hz log power (n = 28; mean partial rho −0.082; Holm p = 0.17), spike rate (n = 29; +0.001; Holm p = 0.97), and line length (n = 29; −0.060; Holm p = 0.28) did not predict the early ictal power rise. The prespecified criterion (Holm p < 0.05 and positive rho) was not met. With additional control for preictal baseline power, line length showed a small positive association (rho +0.106, Holm p = 0.072), which was not significant after correction. Analyses restricted to pairs more than 15 mm from the SOZ and using two alternative ictal targets found no Holm-significant effects. These results indicate that, in this cohort, proximity to the clinical SOZ accounts for the observed association between interictal abnormality and early ictal recruitment outside the SOZ. Limits include clinical SOZ labels, one short interictal clip per patient, noisy high-frequency power estimates, approximate fsaverage Euclidean distances, and limited power to exclude effects smaller than about |rho| = 0.09. The original analysis code, archived inputs, hashes, plan, run logs, and results are included in the supporting files.

stereo-EEG · seizure-onset zone · epilepsy · interictal spikes · high-frequency activity · ictal recruitment · distance · partial Spearman correlation