Public campaigns to encourage early detection of dementia in the developed world have led to identification of more people with mild cognitive impairment (MCI) or subjective cognitive decline (SCD). Early dementia diagnosis enables earlier information and support, including symptomatic treatments where appropriate. In clinical trials, detection of those with “prodromal dementia,” identified from cognitive symptoms and stratified by biomarkers (Schneider, 2010), enables potential disease modifying treatments to be targeted early in the disease process, where success is more likely.