Classification, diagnosis and treatment of vascular dementia.

Vascular dementia (VAD) is considered to be the second most common cause of dementia in Europe and the US. In Asia and many developing countries, it is more common than dementia of the Alzheimer's type (DAT). VAD is the most preventable form of dementia associated with later life. The pathogenesis of VAD is multifactorial, and it represents a heterogeneous, not a homogeneous, clinical entity. Classification of VAD by pathogenesis is important for its prevention and treatment. Control of the risk factors for VAD reduces its incidence and stabilises or improves cognitive performance following stroke. Proper diagnostic evaluation of VAD requires: (i) a well defined quantitative assessment of the cognitive deficits present; (ii) assessment of risk factors for stroke; (iii) identification of cerebral vascular lesions by history, neurological examination and neuroimaging; (iv) exclusion of other causes of dementia; (v) establishment of a positive diagnosis of possible, probable or definite VAD versus DAT or mixed VAD/DAT; and (vi) identification of the temporal relationship between cognitive deficits and cerebral vascular lesions. VAD can be subdivided into 8 major types, as follows: (i) multi-infarct dementia secondary to large cerebral emboli [type 1]; (ii) strategically placed infarctions causing dementia [type 2]; (iii) multiple subcortical lacunar lesions secondary to atherosclerosis or degenerative arteriolar changes [type 3]; (iv) Binswanger's disease (arteriosclerotic subcortical leukoencephalopathy) [type 4]; (v) mixtures of types 1, 2 and 3 [type 5]; (vi) haemorrhagic lesions causing dementia [type 6]; (vii) subcortical dementia secondary to hereditary factors (type 7); and (viii) mixtures of DAT and VAD (type 8). Treatment is dictated by the pathogenetic subtype of VAD that is present.