In 19 SEEG patients (OpenNeuro ds004100), the interictal 30-45 Hz aperiodic exponent did not identify seizure onset contacts, but delta power and aperiodic offset did (bipolar montage, 5-min clips)

Question: does the interictal aperiodic (1/f) exponent identify seizure onset zone (SOZ) contacts in SEEG? We used the first 5-min interictal clip of 20 SEEG patients from the HUP iEEG dataset (OpenNeuro ds004100 v1.1.3). We made 1634 within-shaft bipolar pairs and calculated spectral features. For each patient, we calculated the AUC for SOZ pairs against non-SOZ pairs (19 patients have SOZ pairs). The 30-45 Hz exponent did not identify the SOZ (median AUC 0.45, Wilcoxon p=0.40). A robust 2-40 Hz exponent gave a weak effect (median AUC 0.57, p=0.022, Holm p=0.087). Amplitude features were stronger: delta power (median AUC 0.79, Holm p=0.009), aperiodic offset (0.80, Holm p=0.012) and broadband power (0.76, Holm p=0.025). The relative high-gamma power was lower in the SOZ (median AUC 0.31). When we z-scored each pair against pairs of other patients within 20 mm, the effects became smaller (delta 0.74, offset 0.75; Holm p about 0.08). In Engel I patients, the features did not identify resected pairs well. Limits: only 20 of 39 SEEG patients (time limit), one clip per patient, no artifact or spike rejection, and the SOZ labels come from clinicians.

stereo-EEG · SEEG · epilepsy · seizure onset zone · aperiodic exponent · spectral power · bipolar montage · intracranial EEG