AGE-RELATED-CHANGES IN BRAIN .2. POSITRON EMISSION TOMOGRAPHY OF FRONTAL AND TEMPORAL-LOBE GLUCOSE-METABOLISM IN NORMAL SUBJECTS

While many neuropsychological studies have demonstrated age-related pe rformance alterations in tests thought to reflect frontal and temporal lobe function, there is little direct observation and comparison of t hese hypothesized brain changes in vivo. The cerebral glucose metaboli sm of frontal, temporal, and cerebellar regions was examined in 40 you ng ((X) over bar = 27.5 +/- 4.9) and 31 elderly ((X) over bar = 67.6 /- 8.8) normal males using PET-FDG. Univariate analysis showed age-rel ated metabolic reductions in all frontal and temporal lobe regions. Th e reductions ranged from 13%-24% with the greatest changes in the fron tal lobes. Multiple regression analyses showed a stronger age relation ship with frontal lobe than with temporal lobe metabolism. The dorsal lateral frontal lobe was the region that appears to change most within the frontal lobes. Examination of the temporal lobe showed that age c ontributed equally to the metabolic variance of both the lateral tempo ral lobe and hippocampus. These results suggest that age-related metab olic changes exist in both frontal and temporal lobes and that the fro ntal lobe change is greater.