Scientific Program of the 9th Canadian Congress of Neurological Sciences 9e Congrès Canadien des Sciences Neurologiques

Twenty-four patients of comparable age, blood pressure and degree of dementia were classified by an 'Ischemic Score based on clinical features into 'ischemic' and 'primary degenerative' dementia. Regional cerebral blood flow was measured by the intracarotid 133 Xe method. Both groups showed a decreased proportion of rapidly clearing brain tissue (largely gray matter). CBF per 100 g brain per minute was normal in the primary degenerative group but low in the ischemic group. This suggests that blood flow is adequate for the metabolic needs of the brain in primary degenerative dementia but inadequate in ischemic dementia. There was no correlation between the degree of dementia and CBF in the primary degenerative group but an inverse relationship existed in the ischemic group. Reactivity of blood vessels to reduction of pC02 was normal in both groups. Selected cases of ischemic dementia may benefit from vasoactive drugs, anticoagulants or surgery.