By virtue of the spatial sharpening and removal of ambiguity with CSD, low-alpha/theta and high-alpha may be concisely quantified as means across sites spanning these well-defined maxima: P9/10, P7/8, P5/6, PO7/8, PO3/4, O1/2 for low-alpha/theta; PO7/8, PO3/4, O1/2, POz, Oz for high-alpha. Neither the overall topographies of posterior condition-dependent alpha, nor repeated measures ANOVA including Hemisphere (Left, Right) as a within-subject factor, suggested differential alpha asymmetries between groups. Consequently, regional alpha means were subjected to a simpler repeated measures ANOVA (GLM procedure; 53) for Alpha Frequency (low-alpha/theta, high-alpha) and Condition (eyes-closed, eyes-open), with Group (control, responder, nonresponder; or responder, nonresponder for patients only) and Gender (male, female) as between-subjects factors and Age as a covariate. An exploratory analysis was also conducted using Treatment (monotherapy, dual therapy) and Response Group (responder, nonresponder) as between-subjects factors, excluding Gender because of insufficient cell sizes.
