Neuronal loss in the brainstem and cerebellum--part of the normal aging process? A morphometric study of the vermis cerebelli and inferior olivary nucleus.

Based on the known age-related loss of Purkinje cells (PC) in the cerebellum, this study focuses on whether a marked loss of PC occurs in individuals of very high age. The inferior olive, which is intimately connected with the cerebellum anatomically as well as functionally, was also studied. The study group included 15 nondemented and basically healthy cases aged 32-104 years. Linear neuronal density was expressed as number of PC per millimeter tissue measured in the vermis and as neuronal numbers per square millimeter tissue in the inferior olive. The linear PC density clearly decreased with increasing age, R2 = 0.82 and p < .001. The inferior olive showed a small but insignificant age-related neuronal loss. We conclude that aging results in reduced PC density in the vermis cerebelli, further accentuated in the very late stages of life.