In three SEEG patients, 3 mA increased CCEP map size and reliability over 1 mA without extending measured reach

This archived analysis compared single pulse cortico-cortical evoked potential (CCEP) maps at 1, 2, and 3 mA in three patients with stereoelectroencephalography (SEEG). It used 10 CHOCS1 pulses per current at 63 stimulation pairs from OpenNeuro ds003848 v1.0.3. Of 3,589 site-by-recording-pair combinations, median responders per stimulation site increased from 3 at 1 mA to 8 at 3 mA at z > 8, and split-half map reliability increased from Spearman rho 0.10 to 0.30. The gain was largest within 25 mm. Newly detected pairs at 3 mA were not farther from the stimulation pair than responders at 1 mA (median 31.3 vs 31.1 mm, p = 0.85). Baseline standard deviation was stable (3/1 mA ratio 1.01), while the 2–8 ms stimulation artifact increased 2.06-fold. These findings are limited to three patients at one center. Currents were delivered in blocks, with 1 mA first, so current is confounded with time. Only 10 pulses and a 90 ms baseline were used; the z > 3.4 threshold produced many apparent responses at long distances, and there were no expert N1 labels. The evidence supports stronger and more repeatable measured responses at higher current in this sample, but does not show greater response reach or establish a general current requirement for a brain-computer interface.

stereoelectroencephalography · cortico-cortical evoked potentials · electrical stimulation · current dose · map reliability · brain-computer interface · OpenNeuro