A median of 10 pulses predicted reliable CCEP maps in 13 SEEG patients, with no detected drift

We estimated how many single electrical stimulation pulses are needed to form a reliable cortico-cortical evoked potential (CCEP) map in a second center. We analyzed one inferred 1 Hz train from each of 13 patients in OpenNeuro ds006254 v1.0.0. For the primary feature (15–100 ms responses from recording pairs at least 10 mm from the stimulated pair), the median single-pulse split-half correlation was 0.47. The Spearman–Brown estimate was 10.0 pulses for a map correlation of 0.9 (95% CI 6.1–13.9; range 1.8–51.1). The measured split-half correlations agreed with the prediction through the tested pulse counts (median difference −0.005; maximum −0.049), making the prediction slightly optimistic. Seventeen pulses were sufficient for 11 of 13 patients. Sensitivity analyses gave median estimates of 14.0 pulses for a 15–300 ms response window and 13.3 pulses using pairs at least 15 mm away. We found no evidence of map drift during the trains (sign-flip p = 0.89). Binary detection of responsive pairs was less reliable: median AUC was 0.80 with five pulses, and the noisy reference labels make this a lower bound. Each patient contributed only one stimulation site, pulses and the stimulated pair were inferred from the artifact, and estimates above half of each train are extrapolations. The comparison with a prior center is not a controlled test because centers differed in protocol and pair selection.

cortico-cortical evoked potentials · stereo-EEG · SEEG · electrical stimulation · split-half reliability · Spearman-Brown prediction · brain-computer interface · OpenNeuro ds006254