The three measures of peak variability (see above), from all subjects, were entered into separate one-way ANOVAs with a within-subject factor of data source (raw EEG, CSD interpolated data, and back-projected IC). All three ANOVAs showed a significant effect of data source (all F > 3.4, all p < 0.05) and were therefore followed-up with paired-samples t-tests. These analyses indicated that there was no difference in variability when measured from the CSD interpolated data and the back-projected IC data (all t < 1, all p > 0.1), but the variables computed from the raw channels were significantly more variable than the variables computed from the spatially filtered sources. The data are presented in Table 2. Based on these results, the following analyses of group differences in variability were performed using the spatially filtered data rather than the raw EEG.
