Grey-white junction pairs had higher distance-adjusted CCEP N1 rates, but not after correction, in six STReEF patients

We examined whether stimulation pairs with contacts labeled at the grey-white junction produced more widespread cortico-cortical evoked potential (CCEP) N1 responses than grey-matter pairs in the SEEG patients of OpenNeuro ds005448 (STReEF), using expert-checked N1 peaks. The planned white-matter-only versus grey-matter comparison was not possible: only one stimulated contact had a white-matter-only label, and there were no white-matter-only pairs. A pre-outcome plan addendum therefore compared junction pairs (at least one contact labeled both white and grey matter) with grey-matter pairs in six patients with at least two pairs of each class. The primary distance-adjusted response-rate difference was +0.101 (95% CI 0.045 to 0.176); all six patient differences were positive (exact one-sided sign-flip p = 0.031), but the Holm-adjusted p value was 0.125. Sensitivity and exploratory results are reported in the text. Tissue labels do not measure distance to the grey-white border, pair classes were not randomly assigned, and the analysis included six patients; the result therefore does not establish a causal effect of stimulation at the junction.

stereo-EEG · SEEG · cortico-cortical evoked potentials · CCEP · N1 response · white matter · grey matter · OpenNeuro · STReEF