Conceptual background to vascular cognitive impairment

The current criteria for vascular dementia use a paradigm that first diagno ses dementia on the basis of Alzheimer-type criteria and then superimposes upon this vascular events and risk factors to convert a diagnosis of Alzhei mer disease to one of vascular dementia. There are two fundamental flaws wi th this approach. First, the neuropsychological features of Alzheimer disea se are not the same as those for vascular dementia and so use of the curren t criteria will fail to diagnose many cases, particularly those in whom mem ory loss is not prominent. Second, progression of vascular dementia should be modifiable by adjustment of risk factors and possibly, by the use of neu roprotective agents. Given this, it is absurd to wait until patients are fr ankly demented. It is far more appropriate to detect patients at risk of de veloping cognitive loss as soon as possible. This could be in the earliest symptomatic stage (vascular cognitive impairment) or even prior to this (br ain-at-risk) stage. New criteria, based on evidence rather than on supposit ion, that focus on early disease are urgently needed.