Decreased cerebral blood flow precedes multi-infarct dementia, but follows senile dementia of Alzheimer type.
A 7-year prospective study among 181 neurologically normal elderly volunteers (mean age, 70.6 years) revealed an incidence of 3.3%, or 0.47% new cases per year, for Alzheimer's disease (SDAT) and 5.5%, or 0.78% new cases per year, for multi-infarct dementia (MID). The unusually high incidence of MID is considered to reflect preselection of a large percentage of volunteers (48.6%) with risk factors for (but without symptoms of) atherothrombotic stroke. Of 88 volunteers at risk of stroke, 11.4% developed MID within 7 years. In MID patients, cerebral blood flow (CBF) values began to decline around 2 years before onset of symptoms, while in SDAT patients, CBF levels remained normal until symptoms of dementia appeared; thereafter, CBF declined rapidly.
D000368:Aged; D000544:Alzheimer Disease / Q000000981:diagnostic imaging / Q000503:physiopathology*; D000704:Analysis of Variance; D002560:Cerebrovascular Circulation; D003704:Dementia / Q000000981:diagnostic imaging / Q000503:physiopathology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012306:Risk; D014057:Tomography, X-Ray Computed