Diagnosis of Alzheimer's disease in asymptomatic individuals: a historical perspective.

The diagnosis of Alzheimer's disease (AD) based on biomarkers of the pathological process represents a significant change from previous criteria, which required the presence of dementia for AD diagnosis. These new criteria create difficulties in disclosing the diagnosis of AD to asymptomatic individuals. A similar example exists in the history of cognitive and behavioral disorders, where the risk of developing dementia paralytica (DP), a form of neurosyphilis (NS), could be detected even in the asymptomatic phase. Treatment in this phase of DP or in its early symptomatic phase was successful due to the discovery of new therapeutic modalities and new evolutionary biomarkers, which are not yet widely available in AD. This type of biomarker was very important in NS and will certainly be in AD, allowing for faster and less expensive clinical trials.