For linked-mastoid ERPs, no significant main effects (all F[1, 37] ≤ 1.09, all p ≥ .30) or interactions (all p ≥ .11) involving group were observed in any of the analyses. or N1 amplitude, a significant main effect of hemisphere, F(1, 37) = 5.66, p = .02, confirmed a left-greater-than-right asymmetry, but the monotonic increase of N1 (M ±SD, weak to strong, −1.09 ± 1.16, −1.31 ±1.15, −1.47 ± 1. µV) was insignificant, F(2, 74) = 1.98, p = .15, ε = 0.9301. There were no significant effects for N1 latency (patients vs. controls, 316 ±132 vs. 326 ±110 ms; weak to strong, 322 ±134, 331 ±119, 309 ±112 ms). For P2 amplitude, highly significant main effects of intensity, F(2, 74) = 15.1, p < .0001, ε = 0.9885, and site, F(1, 37) = 9.72, p = .003, confirmed a monotonic increase (weak to strong, 8.71 ±4.69, 9.10 ±4.26, 11.31 ± .69 µV) and greater P2 at z than Pz (10.29 ±5.12 vs. 9.12 ± .11 µV), but there was no difference between patients and controls (9.75 ±5.36 vs. 9.66
