Effects of hormone replacement therapy and aging on cognition: evidence for executive dysfunction

The present study was designed to explore whether the frontal lobe hypothesis of cognitive aging may be extended to describe the cognitive effects associated with estrogen use in postmenopausal women. Postmenopausal estrogen-only users, estrogen + progesterone users, and non-users (60-80 years old), as well as young, regularly cycling women (18-30 years old) completed an item and source memory task. Since source memory is thought to rely more on executive processes than item memory, we hypothesized that aging and estrogen effects would be greater for source memory than for item memory. Neuropsychological tests explored whether the effects of aging and estrogen use were revealed on other tests of frontal lobe function. Results from the experimental task revealed greater aging and estrogen effects for source memory than for item memory, and neuropsychological results revealed aging and estrogen effects on a subset of tests of executive function. Women on estrogen + progesterone therapy did not outperform non-users, suggesting that the addition of progesterone to hormone therapy may mitigate the benefits induced by estrogen use alone. Overall, findings support the hypothesis that estrogen use may temper age-related cognitive decline by helping to maintain functions subserved by the frontal lobes.