The 30–45 Hz aperiodic exponent did not separate seizure-onset channels in 31 SEEG patients

We tested whether the interictal aperiodic (1/f) exponent identifies clinician-labelled seizure-onset zone (SOZ) channels in stereo-EEG. We used OpenNeuro ds004100 (HUP), 31 SEEG patients, the first 120 s of interictal run-01, and within-shaft bipolar channels. For each patient, we calculated the area under the receiver operating characteristic curve (AUC) for each feature in SOZ versus non-SOZ channels. The 30–45 Hz exponent was the primary feature and was chosen before analysis. It did not separate SOZ channels: median AUC 0.52, IQR 0.31–0.69, Wilcoxon p = 0.95; 16/31 patients had AUC above 0.5. Candidate spike rate (AUC 0.72, p = 1.0e-4), 1–40 Hz power (0.71, p = 8.2e-5), 80–150 Hz power (0.67, p = 6.6e-4), and line length (0.66, p = 6.1e-4) separated SOZ channels in group tests; relative alpha power was lower in SOZ channels (AUC 0.35, p = 7.5e-4). Results were similar in the same-shaft control (aperiodic exponent AUC 0.53, p = 0.67; high-gamma 0.77, line length 0.72). No feature showed a difference in SOZ AUC between seizure-free (n = 18) and failed-surgery (n = 13) patients (all Benjamini–Hochberg q ≥ 0.9). Limits include one short clip per patient, no anatomical normalization, an unvalidated simple spike detector, and normal-approximation tests. Seven SEEG subjects were excluded: four for incomplete downloads, two for too few channels, and one for no SOZ labels.

stereo-EEG · interictal · seizure onset zone · aperiodic exponent · power spectrum · epilepsy · area under the curve · OpenNeuro