Differential aging of the human striatum: longitudinal evidence.

BACKGROUND AND PURPOSE Information about age-related changes in the striatum comes almost exclusively from cross-sectional studies. We examined age-related differences and longitudinal changes in the volume of the striatal nuclei, compared longitudinal measures of changes with their cross-sectional estimates, and addressed the question of differential aging of the basal ganglia. METHODS We measured the volumes of the caudate nucleus (head), the putamen, and the globus pallidus on MR images of 53 healthy adults whose ages at baseline ranged between 20 and 77 years. The measurements were conducted twice, 5 years apart. RESULTS On both measurement occasions, the volume of the neostriatal nuclei (caudate and putamen) but not of the globus pallidus correlated negatively with age. However, longitudinal comparison revealed significant declines in the neostriatal volumes and smaller (but statistically significant) shrinkage of the paleostriatum. In 5 years, the striatal components (caudate, putamen, and globus pallidus) shrunk by 1.21, 0.85, and 0.55 standard deviation units, respectively. The average annual shrinkage rate was 0.83% in the caudate nucleus, 0.73% in the putamen, and 0.51% in the globus pallidus. CONCLUSION Although cross-sectional estimates suggested preservation of some striatal nuclei, longitudinal shrinkage of the whole striatum was evident even in a selected group of healthy adults. Moreover, the magnitude of observed longitudinal change was greater than predicted from cross-sectional studies.