The alpha contrast test detected no WM label difference in 14 SEEG patients under patient independence and null sign symmetry

We tested whether alpha contrast after stimulation differed between source white matter label groups on the same SEEG shaft. We used public OpenNeuro ds005169 version 1.0.0. Both contacts in each pair had WM=1 or WM=0. WM=0 does not prove a grey matter location. The test used 14 patients, 74 records, and 261 paired shaft-records. Each patient had equal weight. The mean WM=1 minus WM=0 difference was -0.322 dB. The percentile 95% patient bootstrap interval was [-0.805, 0.127] dB. The exact two-sided patient sign-flip p value was 0.2203. This test requires independent patients and null sign symmetry. It did not detect a difference at 0.05. The result does not prove equal responses. This was an exploratory secondary study of the cohort used in the cited alpha and distance studies. Five fixed checks and added descriptive checks are reported. Fresh pinned raw ranges passed for one record per patient. An offline repeat matched 26 result files. The package preserves source spectra, labels, code, results, figures, hashes, source versions, and repeat instructions. The data lack a sham control. The study cannot establish a causal mechanism or clinical benefit.

intracranial EEG · SEEG · white matter · alpha contrast · cortical stimulation · visual effects · patient-level inference