Age-related decline of psychomotor speed: effects of age, brain health, sex, and education.

A cross-sectional study into age-related decline of psychomotor speed is reported. A newly introduced choice response task was used, involving three conditions: simple reaction time (SRT), choice reaction time (CRT), and CRT with stimulus-response incompatibility. Subjects were 247 volunteers, aged 20 to 80 yr. in seven age levels. Although all subjects thought themselves to be normal and healthy, a post hoc division could be made based on biological life events (BLE, mild biological or environmental factors that can hamper optimal brain functioning, such as repeated general anesthesia). Performance was poorer by subjects who had experienced one or more such event: slowing was comparable to the effect of age, especially in the more difficult task conditions. There were significant effects of sex and education, men being consistently faster than women, and more highly educated subjects performing better than subjects with only low or medium education. These findings replicate observations from other test methods. They are also in line with several other studies giving interactions between the effects of aging and physical fitness. This study questions the validity of much research on aging, as the data suggest that a more rigorous health screening for biological life events in subjects recruited from the normal, healthy population can reduce performance effects normally ascribed to aging.