CSD-ERSP plots were also less stable than the overall sample but nonetheless revealed similar condition effects, with greater ERS for target and particularly novel stimuli at mid-frontocentral sites compared to nontargets (Fig. 8B, row 1). However, alpha ERD over posterior sites was markedly reduced (Fig. 8B, row 2), even when compared with the overall sample of patients (cf. Fig. 6). A descriptive post-hoc ANOVA for alpha ERD (tfPCA factor 610–9 at lateral centroparietal and parietal-occipital sites; cf. Tab. 4) yielded a significant effect of group (F[2,39] = 3.56, p = .04), stemming from greater alpha ERD for controls (−1.06 ±1.30) than nonconverters (−0.59 ±1.22) and converters (0.21 ±0.83). Simple effects revealed a significant difference between converters and controls (F[1,39] = 5.77, p = .02), a marginal difference between nonconverters and controls (F[1,39] = 3.00, p = .09), but no significant difference between converters and nonconverters (F[1,39] = 2.26, p = .14). This pattern of group differences was confirmed by the non-parametric ADF test, although converters also differed significantly from nonconverters in the Welch-James test statistic (W/J[1,6.415] = 9.48, p =
