An earlier application of the present wavelet-based time–frequency analysis (Ford et al. 2008) revealed differences in P3 amplitude between schizophrenic and control samples with associated lower δ total power. The low P3 amplitude in the alcoholics of the present study, however, was not associated with a reduction in cross trial phase synchrony (phase-locking factor) at δ or θ frequencies as was the case with the reduced P3 in schizophrenics (Ford et al. 2008). Differences in task characteristics and in stimulus modality confound the diagnostic differences and make direct comparison challenging. Further, the small sample size leaves open the possibility that the study may have been underpowered to detect alcoholic-control differences. Nonetheless, the lack of a difference in phase-locking factor between alcoholics and controls is of note. Smaller δ total power in association with the P3 peak in alcoholics in the absence of a phase-locking factor difference implies that δ oscillations are intact in alcoholics, but that relative to controls, they have dampened inhibitory processing-related modulation of the magnitude of the response
