Seven SEEG spectral features were equivalent within 0.2 within-patient SD across mirror-matched hemispheres in 152 RAM patients

We tested whether spectral features of stereoelectroencephalography (SEEG) bipolar pairs differed between right hemisphere locations and their mirrored left hemisphere locations. We used archived per-pair spectra from 261 RAM patients in OpenNeuro ds004789 (discovery) and ds004809 (replication), matching pairs within 10 mm in MNI space. In the 152 patients with at least five matches (107 discovery, 45 replication; 3,405 pairs), none of seven features showed a significant discovery effect, so none replicated. For all seven features, the pooled 90% confidence interval for the standardized within-patient difference was within ±0.2 SD. Relative alpha had the largest pooled difference (dz = −0.093, 90% CI −0.178 to −0.009; raw two-sided p = 0.117); a small right-lower-than-left difference is possible but was not shown. Matched right pairs were approximately 0.6 mm more posterior. Sensitivity analyses did not change the findings. A post hoc positive control detected alpha differences when right pairs were shifted 20 mm anteriorly or posteriorly. Clinical electrode placement, one 60 s task segment per patient, unknown focus side and language dominance, and MNI-only matching limit interpretation.

stereoelectroencephalography · SEEG · hemispheric asymmetry · spectral features · intracranial EEG · mirror matching · RAM