Converging evidence from epidemiological studies suggest that the pathophysiological process of Alzheimer's disease (AD) begins years, if not decades, prior to the diagnosis of clinical dementia. In this regard, the paper written by Waal et al in this issue (see page 67) represents an advance in our understanding of the relationship between AD genetic risk (as represented by the APOE ε4 allele) and EEG phenotype.1

The presence of the APOE4 allele is a well known risk factor for …