Cognitive impairment after stroke.

The concept of vascular dementia is undergoing revision. The multi-infarct model and the Alzheimer's model of dementia, usually referred to as 'multi-infarct dementia', are gradually being replaced by a much broader concept of vascular cognitive impairment. This conceptual evolution reflects a more profound understanding of the pathogenic mechanisms that underlie this complex syndrome. As a consequence of this revision new diagnostic criteria have been established during the past 25 years, resulting in new problems with regard to precise disease definition and limited inter-rater reliability. The particular criteria chosen by a clinician or investigator to diagnose vascular dementia have a major impact on epidemiology, disease management and health economic estimates.