Examining the relationship between computed tomography and neuropsychological measures in normal and demented elderly.

Correlational analysis of CT and neuropsychological measures in patients with dementia revealed more predictive relationships in degenerative and vascular subgroups that in a multi-aetiology group. Normal and dementia patients were then matched for age, sex and educational background, and analysed together. The ventricular/brain ratios of the bodies of the lateral ventricles and of the third ventricle correlated most highly with neuropsychologic performance. Canonical analysis revealed a correlation coefficient of 0.725 between the sets of CT and neuropsychological measures, which increased to 0.78 when a degenerative subgroup only was considered. Discriminant function analysis indicated that the combination of CT and neuropsychological measures was more powerful in discriminating normals from dementia patients than CT or neuropsychological measures alone.