Brain atrophy parameters of very old subjects in a population-based sample with and without dementia syndrome

Atrophy parameters of the brain vary with age in healthy subjects. The aim of the study was to determine the range of atrophy parameters in subjects with very old age. Population-based data are especially necessary in order to evaluate atrophy parameters of healthy old persons in clinical settings and for the diagnosis of dementia diseases. 254 subjects in a population-based sample were investigated by a cranial computerized tomography (cCT). Age ranged from 70 to 99, 78 were 80-89 years old and 43 over 90 years of age; 24 demented subjects were diagnosed according to DSM-III-R. A planimetric analysis of the extracerebral CSF-space (ECSF) and relative area of the ventricles (VBR) was performed. VBR and ECSF were used as primary atrophy parameters. The VBR, ECSF and other structural brain parameters for subjects of very old age are described after exclusion of dementia cases according to clinical diagnosis. A statistically significant age effect could be demonstrated as well as a dementia effect for the younger age groups (70-89). No difference in the atrophy parameters between the diagnostic groups, however, were found for the oldest groups (90 and older); for the very old subjects the scores of demented and non-demented participants were entirely within the same range. The age effect on atrophy parameters in non-demented subjects in very old age reaches the range of atrophy parameters, which is found in dementia. The question remains wheather the reason for this is a benign senescent brain atrophy or whether the amount of atrophic changes in very old age may explain the enhanced vulnerability for the development of dementia syndromes in very old age and the steeply increasing incidence of dementia or whether there is an incipient brain atrophy in more or less all very old subject and they will develop dementia if they do not die beforehand.