well as decreased alpha phase coherence compared to controls. Duffy and Als (2012) employed CSD transformed spectral coherence of the resting EEG in 463 children with ASD and 571 neuro-typical controls in order to see the classification accuracy based on the diagnosis. They found that coherence factors successfully discriminated ASD from the controls. Coherence values for the short-range pairs were lower while the values in the long-range pairs were both higher and lower in the ASD groups compared to the controls. In their follow-up study, Duffy et al. (2013) used the same measure (i.e., CSD transformed spectral coherence) in 430 children with ASD, 26 children with Asperger syndrome, and 554 neuro-typical controls in order to determine the classification pattern among all three groups, especially to see whether the 26 children with ASD were systematically separable from the larger population of 430 subjects with ASD. They found that coherence factors as used in discriminant function analysis could successfully separate Asperger syndrome from the ASD population and from the controls with significant classification success. In these studies, although the authors have not directly compared the raw EEG potentials with CSD measures, they state that they have employed surface Laplacian methods in order
