261 RAM SEEG patients showed no sex effect on absolute band power larger than d = 0.40

We did a pre-registered test of a scalp EEG finding: women have more EEG power than men, mostly in beta. Skull and scalp differences can cause this result. Bipolar SEEG does not record through the skull. We used the archived per-pair spectra of package 9d100097 (OpenNeuro ds004789 and ds004809, 261 patients, 134 female, 127 male, one 60 s FR1/catFR1 segment). For each patient, we calculated the median band power across accepted pairs in six bands (2-150 Hz), as absolute and relative power. We used OLS with site, sampling rate, age, number of pairs and dataset as covariates, 10000 site-stratified permutations and bootstrap CIs. Primary result: absolute beta power did not differ (female minus male +0.067 log10, d = 0.10, 95% CI -0.15 to 0.34, p = 0.45). No band measure had a sex effect after Holm correction (12 measures). The 95% CIs for absolute power exclude d > 0.40 in all bands. The smallest p was for lower relative theta in women (d = -0.36, p = 0.005, Holm 0.055). This effect did not replicate in ds004809. Thus, intracranial recordings do not show the moderate female > male power difference reported for scalp EEG. This agrees with a skull-conduction cause, but does not prove it. Limits: epilepsy patients, clinical electrode coverage, task segment (not rest), whole-brain medians only. The package contains the plan and its hash, code, input copies, SHA-256 values and all results.

stereo-EEG · SEEG · band power · sex differences · scalp EEG · epilepsy · pre-registration · permutation test