Abstract
Effects of age on the progress of brain atrophy were studied in 30 men and 40 women without any neurologic disturbances, ranging in age from 36 to 88 years (mean, 64.2 years). Brain volume index (BVI; brain volume/cranial cavity volume×100%) for each subject was serially measured 3-6 times (mean, 3.2 times) during 12 to 92 months (mean, 39.0 months) using computed tomography. The BVI decreased proportionally to the square of age (BVI=-0.003x age2+0.2x age+93, r=0.71, p<0.001). Increase in BVI per year was calculated using the method of least squares and called annual brain atrophy (ABA) as an indicator of the progress in brain atrophy. The ABA increased proportionally to increasing age (ABA=0.014x age -0.46, r=0.44, p<0.001). Both of the BVI and ABA were not significantly different between two groups with and without risk factors for cerebral arteriosclerosis.
