Latency to peak was compared in the two groups using a repeated measures ANOVA with three levels: data source (EEG, CSD, or ICA), data type (ERP or median of single-trials) and group (ASD or TD). The only significant effect was the main effect of group, F(1,23) = 9.4, p < 0.01 which reflected the fact that latency to peak was faster, on average 18 ms faster, in the ASD group than the TD group, regardless of the data source or the data type. Table 4 presents P1 amplitude and latency values in each group as calculated from the different sources of data. The table illustrates that, as expected, when calculated from the median of single-trials rather than the peak of the ERP, P1 amplitude is larger, whereas the latency of the peak does not differ.
