Brain Atrophy During Aging: A Quantitative Study Using Computed Tomography

Abstract

Using computed tomography, the authors studied brain atrophy during aging in 483 males and 497 females with no neurologic disturbances, ranging in age from 10 to 88 years. They measured cerebrospinal fluid (CSF) space volume and cranial cavity volume above the level of the tentorium cerebelli and calculated a brain atrophy index (BAI):BAI (%) = 100% X (CSF space volume/cranial cavity volume). Both CSF space volume and the BAI started to increase significantly after the thirties in both men and women (P less than 0.001). While the rate with which the brain atrophied accelerated constantly during aging in females, the rate of atrophy in men in their thirties and forties was more than twice that of women of the same age; the rate then declined in men in their forties and fifties. Both CSF space volume and the BAI increased exponentially with increasing age after the thirties, continuing to increase until the eighties in both men and women.