Vascular dementia, also known as Multi-infarct dementia, is the second most common form of dementia after Alzheimer's disease in older adults. The term refers to a group of syndromes caused by different mechanisms all resulting in vascular lesions in the brain. Early detection and accurate diagnosis are important, as vascular dementia is at least partially preventable.

Vascular dementia is classified by three subtypes. Arteriosclerotic - where there has been a reduction of oxygen to the brain over time; Vascular - which is a sudden onset of dementia following a stroke; and Multi-infarct - where a gradual onset of dementia usually follows a series of mini-strokes.

In the majority of cases, vascular lesions occur as a result of both diffuse cerebrovascular disease and also focal lesions. Mixed dementia is diagnosed when patients have evidence of Alzheimer's disease and Cerebrovascular disease. In fact Vascular dementia and Alzheimer's disease often coexist, especially in older patients with dementia.