Age and sex differences in the cerebellum and the ventral pons: A prospective MR study of healthy adults

BACKGROUND AND PURPOSE: The human brain exhibits a complex pattern of diffe rential aging. The purpose of this study was to examine whether age differe nces in the volume of cerebellar regions and the ventral pens are different ial or generalized, whether the age-related shrinkage is linear or exponent ial, and whether there are sex differences in the size of the cerebellum an d pens. METHODS: The volumes of the cerebellar hemispheres (excluding the vermis an d the peduncles), the vermis, and the ventral pens were estimated from the prospectively acquired MR scans of 190 healthy volunteers (aged 18-81 years ). The relation between regional volumes, age, and sex was assessed while t aking into account differences in body size (height). RESULTS: We found a moderate age-related reduction in the volume of the cer ebellar hemispheres and the cerebellar vermis, In contrast to previous find ings that suggested differential vulnerability of the posterior vermis, the age-related shrinkage of the vermian lobules was uniform-about 2% per deca de. In accord with all reports in the literature, the size of the ventral p ens was unrelated to age. The volume of the cerebellar hemispheres, the ver mis, and the ventral pens were larger in men, even after adjustment for hei ght. The magnitude of the sex difference was the largest in the hemispheres and the anterior vermis, and the smallest in the lobules VI-VII (declive-f olium-tuber). CONCLUSION: Moderate age-related shrinkage of the cerebellum and lack of ag e-related differences in the ventral pens are robust phenomena. However, in all likelihood, the effects of age on the cerebellum are not differential but uniform. The cerebellum and the pens are larger in men than in women an d the difference is especially pronounced in the cerebellar hemispheres and the anterior vermis.