Vascular cognitive impairment and vascular dementia.

The criteria for vascular dementia (VaD) depend on first diagnosing dementia using Alzheimer-type criteria, upon which are superimposed vascular events, usually following a stroke model. This if often inappropriate, however, as memory loss is not always prominent in VaD. Alzheimer-type criteria will not detect these patients, and much brain injury can occur without resulting in classical features of stroke. VaD is often only diagnosed when dementia is clinically manifest, already too late to influence the early progression of the disease. Moreover, the predominating consensus-based criteria have demonstrably poor reliability. These shortcomings in the diagnosis of VaD have led to the development of the concept of vascular cognitive impairment (VCI), a broader term that is intended to detect cognitive loss before the dementia advances beyond effective treatment. Criteria for VCI are in the early stages of development. A lack of data on the beginnings of cognitive loss has inhibited their formalization, but it appears that the level of cognition should be set at a sensitive rather than a specific level. Similarly, for routine purposes, neuroimaging evidence of any cerebrovascular disease may be sufficient to document VCI and specific localization is not required. The current clinical criteria for VaD are probably not applicable for the diagnosis of VCI since the presence of focal signs is inappropriate, and stepwise progression is more supportive than diagnostic of VCI. The purpose of defining the new concept of VCI is to identify preventable risk factors. Importantly, not only physical health but also mental health should be monitored and treated.