[Quantitative rheoencephalographu in normal and pathological ageing (author's transl)].

A method of quantitative rheoencephalography estimating the rapid cerebral blood flow, defined by the clearance of Xe 133 is applied to normal, hemiplegic and demented subjects. In the normal child the flow is twice that of the elderly. In adults a decrease of 13% is observed in the fifties. The flow is decreased in both hemispheres of the hemiplegics. The cerebral flow is decreased in the two clinical groups of demented patients (vascular and non-vascular); different values of flow are obtained in these two groups.