Neuropathologic substrates of ischemic vascular dementia

Ischemic vascular dementia (IVD) is a relatively uncommon entity, in the co urse of which multiple ischemic brain lesions result in progressive cogniti ve and memory impairment. Ischemic brain lesions may also aggravate the neu ropsychologic deficit of Alzheimer disease (AD). In this review we summariz e our experience based upon autopsy examination of the central nervous syst em in 20 patients (age range 68-92 years) enrolled in a longitudinal invest igation of structural, neurochemical, functional neuroimaging, and neuropsy chologic components of IVD, especially dementia associated with cerebral mi crovascular disease. While cystic infarcts were present in the CNS of 5 pat ients, the most commonly observed neuropathologic abnormalities were lacuna r infarcts and microinfarcts-both types of lesion were encountered in over half of patients' brains. Evidence of (remote) hippocampal injury was found in 11/20 patients. Severe atherosclerosis and arterio/arteriolosclerosis w ere both associated with the occurrence of multiple lacunar infarcts. Prono unced cerebral amyloid angiopathy (CAA) was noted in a single patient, who also showed other microscopic changes of severe AD. While fairly unusual as a nosologic entity, IVD appears to correlate with widespread small ischemi c lesions distributed throughout the CNS. We furthermore propose an approac h to quantifying the burden of ischemic vascular and parenchymal disease th at may be associated with a dementia syndrome. A brief review of neuropatho logic features of vascular dementia (both familial and sporadic) is present ed.