Common-reference removal does not restore the surface CCEP N1 age-latency control in sampled ds004080 epochs

We tested whether the common reference used for almost all channels in 24 patients from OpenNeuro ds004080 explained a failed surface positive control in an age-latency analysis of cortico-cortical evoked potentials (CCEPs). Using the same archived monopolar epochs (10 stimulation pairs × 4 pulses per patient, averaged at 2048 Hz) and a plan written before re-referencing, we compared adjacent-contact bipolar, common-average, and monopolar derivations with an automatic peak detector. The surface age-latency control remained nonsignificant for bipolar data (n=24, Spearman ρ=−0.22, permutation p=0.31, 95% CI −0.59 to +0.19), common-average data (ρ=−0.26, p=0.22), and monopolar data (ρ=−0.28, p=0.19). Thus, common reference removal did not restore the control. The depth association changed from ρ=+0.18 (monopolar) to ρ=−0.23 (bipolar; n=23, p=0.28); neither was significant. The earlier nominal depth-minus-surface association (ρ=+0.47, p=0.022, monopolar) was absent after bipolar derivation (ρ=−0.05, p=0.83). Common-mode correlation, edge peaks, low sampling, and automatic detection without expert response review qualify interpretation. With only 40 pulses per patient and 23–24 patients, sensitivity is low; the null result does not exclude an age association near ρ=−0.4.

cortico-cortical evoked potentials · CCEP · N1 latency · age · stereo-EEG · reference · bipolar derivation · OpenNeuro · ds004080