AUD, controlling for CUD, sex, and age. For alpha oscillatory activity, ANCOVA revealed a significant main effect of AUD (F(1,40) = 8.12; p = 0.007; η2 = 0.163) but not CUD (F(1,40) = 3.11; p = 0.082), which indicated that those with AUD had blunted occipital alpha responses compared to those without AUD from 300 to 550 ms (Fig. 2). In contrast, our ANCOVA models showed no significant main effects of AUD or CUD on both theta and gamma band oscillations (all ps > 0.10), with the exception of an effect of reduced gamma activity in CUD (F(1,40) = 4.26; p = 0.046; η2 = 0.086). However this effect of CUD on gamma appeared to be driven by a participant with an outlier value (three standard deviations away from overall mean) as the effect was no longer significant upon excluding this data point (F(1,39) = 3.40; p = 0.072).
