Comparison between Alzheimer's disease and vascular dementia: implications for treatment.

Virtually 90% of the elderly with late-onset dementia exhibit neuropathological features consistent with Alzheimer's disease (AD), vascular dementia (VaD) or dementia with Lewy bodies (DLB), alone or in combination. Both AD and DLB reveal extensive senile plaques containing amyloid beta whereas neurofibrillary tangles evident as tau pathology are fewer in DLB, which also bears diffuse cortical Lewy bodies. Interestingly, however, there is considerable overlap between AD and VaD in terms of both risk factors and pathology. Cholinergic deficits are also encountered in VaD, which like AD may respond to cholinergic therapy. Cerebrovascular pathology, ischemic brain damage and autonomic dysregulation resulting in cerebral hypoperfusion appears fundamental in the pathogenesis of late-onset dementias.