ANALYSIS OF BRAIN-WEIGHT .1. ADULT BRAIN-WEIGHT IN RELATION TO SEX, RACE, AND AGE

Abstract

The weights of fresh [human] brains obtained at consecutive autopsies over a period of 5 yr were reviewed. Brains with lesions, such as large tumor, hemorrhage, infarct or edema, were excluded. Analysis of the brain weight of 1261 subjects, aged 25-80 yr, show that the mean brain weight decreases in order from white men to black men to white women to black women. These differences are statistically significant and become apparent at age 6 yr. The rate of decrease for the brain weight after age 25 yr is highest for white men, followed by black women, white women and black men and, except that between white men and white women, the differences are statistically insignificant. Contrary to earlier reports, the mass decreases rapidly after age 80 yr. In evaluating an individual brain weight, it is important to compare it with the norm for each subgroup of a given age.