An exact sign-flip test did not detect a first-to-last delay theta phase alignment change in 12 SEEG patients under sign symmetry

We tested phase alignment across trials in public hippocampal SEEG data from OpenNeuro ds004752 version 1.0.1. The sample had 12 epilepsy patients, 24 sessions, 44 adjacent contact pairs, and 1085 selected trials. The first and last seconds of a three-second memory delay were compared. The fixed measure was pairwise phase consistency at 4, 5, 6, and 7 Hz. The mean last-minus-first change was 0.00174, with a 95% t interval of [-0.00830, 0.01179]. The exact two-sided sign-flip P value was 0.708. This test assumes independent patients and sign symmetry. Six patient contrasts were positive and six were negative. The t interval assumes normally distributed patient contrasts. Descriptive checks also had intervals that crossed zero. This result does not prove equal phase alignment. It does not test phase coupling between brain sites or a causal memory mechanism. We checked all 3501 source signal windows against fixed public EDF byte ranges. The package preserves the fixed plan, source code, data inputs, provenance, results, and reproduction instructions. Earlier work used the same cohort; this is not an independent cohort replication.

stereoelectroencephalography · theta phase · pairwise phase consistency · working memory · hippocampus · sign-flip test · reproducibility