Does the right hemisphere age more rapidly than the left?
It has been hypothesized that the right hemisphere ages more rapidly than the left, but there have been no direct empirical studies aimed at confirmation of that hypothesis. Within the framework of a cross-sectional design, 1,247 subjects, divided into six age groups (20's-70's), were tested with a modified Halstead-Reitan battery. The test scores were analyzed with the Russell, Neuringer, and Goldstein localization key, with each case being evaluated for number of right- and left-hemisphere points. It was found that there was a significant increase in right-hemisphere points with age, with a significant, but less pronounced, effect for left-hemisphere points. The same effect was found in a subsample of nonbrain-damaged medical and psychiatric patients. It was also established on the basis of neurological diagnostic evidence that there was not a coincidental increase in structural lateralized brain damage with age in the present sample. The results were discussed in terms of possible differences in functional organization of the two hemispheres, the general conclusion being that the right hemisphere ages in a different manner than does the left.