Introduction

Vascular dementia is a type of dementia resulting from cerebrovascular disorder. It is not rare that cerebral stroke (infarction or hemorrhage) is followed by typical vascular dementia. There are, however, some patients with vascular dementia who have no preceding episodes of evident cerebrovascular disorder such as stroke or transient cerebral ischemia.

Arteriosclerotic dementia and multiinfarct dementia are terms used for pathological conditions similar to vascular dementia. Although the former term commonly has been used to describe dementing diseases in the elderly, it is very obscure in definition, as if covering every ambiguous dementing condition.

Multiinfarct dementia is a concept proposed in 1974 by Hachinski, Lassen & Marshall, who criticized the existing tendency for dementing disease in the elderly to be overdiagnosed as cerebrovascular dementia. According to Hachinski and colleagues (1974), dementia should be classified in terms of the cause into senile dementia of Alzheimer type and multiinfarct dementia. The former, which is predominant, occurs along with aging changes in the brain, and the latter is caused by cerebrovascular disorder. They stated, on the basis of studies of CBF, that dementia related to cerebral vascular lesions is caused by multiple development of infarcts varying in size, rather than simply by the presence of cerebral arteriosclerosis. This opinion became widely accepted, with an understanding of the concept that the lesion responsible for dementia is not arteriosclerosis itself, but the resultant infarct(s).

Later, however, it was pointed out that cerebrovascular dementia attributable to pathological conditions other than infarction accounts for a substantial proportion of all cases of vascular dementia.