Blood-brain barrier (BBB) permeability in the demented elderly was investigated by use of the ratio of cerebrospinal fluid (CSF) albumin (Alb) to serum Alb (Q-Alb). Subjects with Alzheimer type dementia (AD), vascular dementia (VD), and controls without dementia (C) were investigated. Patients with AD were divided into mild AD (mAD) and severe AD (sAD) by the use of Hasegawa's dementia scale. The Q-Alb and the ratio of CSF α₁-antichymotrypsin (ACT) to serum ACT (Q-ACT) were evaluated. Correlations between Q-Alb and Q-ACT were compared among the groups (mAD, sAD, VD, C). Correlations between Q-Alb and major monoaminergic neurochemicals were also analyzed. It was suggested that BBB permeability was preserved in C group, while it was impaired in the patients with VD. In AD group it appeared to be rather well preserved in mAD, while it seemed to be disturbed in a graded manner according to the progression of dementia.
(Internal Medicine 37: 509-513, 1998)