Computerised tomography and intellectual impairment in the elderly

clinically and by simple psychometric tests have been studied by computerised tomography. The mean maximum ventricular area in the 17 mentally normal subjects was above the upper limit of normal for younger subjects, and there was a broad relationship between increasing ventricular dilatation and increasing intellectual impairment. No such clear relationship was demonstrable for measures of cortical atrophy. Cerebral atrophy, as shown by symmetrical ventri-cular dilatation and widening of the cortical sulci, is considered to underly deterioration of intel-lectual function in the elderly, and many would consider such atrophy to be a function of ageing, and so to be expected in the brains of at least some intellectually normal elderly people (Tom-linson et al., 1968; Dayan 1973). Demonstration of cerebral atrophy in life has hitherto been depen-dent upon pneumoencephalography, which carries a morbidity sufficient for it to be only very rarely justifiable in the investigation of an elderly patient. The development of computerised tomo-graphy has made possible the demonstration of these abnormalities by safe non-invasive means. There appears to be a good correlation between the diagnosis of cerebral atrophy by computerised tomography and pneumoencephalography (Gawler et al., 1976; Roberts et al., 1976). The present investigation uses methods previously described by Roberts et al. (1976) to assess the degree of cerebral atrophy in 17 mentally normal old people, and 49 with varying degrees of intellectual impairment, all carefully studied by simple psychometric methods. MIETHODS Sixty-six patients, 59 of them women, aged 62 t