Interictal 1–40 Hz power showed no distance gradient, while spike rate fell with SOZ distance in 30 HUP patients

We tested whether interictal SEEG features varied with distance from the seizure-onset zone (SOZ) in 30 HUP patients using archived per-pair features from 120-s clips and fsaverage contact coordinates. For each non-SOZ bipolar pair, we measured the 3D distance to the nearest SOZ pair and calculated within-patient Spearman correlations. Broadband log 1–40 Hz power showed no distance gradient (mean rho = −0.035, 95% CI −0.141 to 0.056; Holm p = 0.44) and was not more related to the patient's own SOZ than to pseudo-SOZs from other patients (Holm p = 0.38). In a post hoc comparison, SOZ pairs had a within-patient z score of +0.56 versus +0.03 for non-SOZ pairs within 10 mm (step = +0.50 z, p = 0.0001). Secondary tests found that spike rate decreased with distance (mean rho = −0.162, 22/30 patients negative, p = 0.0012), more for the patient's own SOZ than for pseudo-SOZs (p = 0.0009); the gradient was also present on shafts without SOZ contacts (post hoc p = 0.0097). The spike-rate result was outside the Holm-corrected primary family, although p = 0.0012 remained below 0.05 after Bonferroni correction over 10 secondary tests. Clinical labels may depend on the same interictal features, so the power step may be partly circular. Other limits include template rather than native coordinates, pair midpoints, no white/grey matter control, sparse near-SOZ sampling, one 120-s clip per patient, and upstream rather than recomputed features. Archived records identify the source as OpenNeuro ds004100 but do not establish the exact release analyzed.

stereo-EEG · epilepsy · seizure onset zone · interictal activity · broadband power · spike rate · spatial gradient · HUP · OpenNeuro ds004100