A recent brain-scan study looking at how estrogen affects complex thinking skills has raised new questions about whether menopause hormones can boost a woman's brainpower.

Women have long complained that their brains don't work as well during and after menopause as they did before. They complain of fuzzy thinking, difficulty finding the right words and other signs of cognitive decline.

Recent research has offered conflicting evidence about the impact of menopause and hormone drugs on brain function. Some research has suggested hormones may prevent Alzheimer's and dementia, but data from a major government study of menopause hormones showed just the opposite. That study, the Women's Health Initiative, found that older women who used menopause hormones were at higher risk for dementia than women in the study who didn't take hormones.

So what's the answer? There's growing evidence that hormones can both help and hurt the brain -- it all depends on when women use them. It appears that women who use hormones close to menopause -- when their bodies are just experiencing a loss of estrogen -- may show improvements in certain areas of cognitive function. But older women who take hormones long past menopause may be harmed by the drugs.

Regaining Skills

A recent Harvard study of 52 menopausal women between the ages of 40 and 60 showed that hormones may help restore complex thinking skills muddled during the hormonal chaos of menopause. At the study's outset, the women were all given a variety of tests to determine their baseline levels for various cognitive functions. Then half the women were given estrogen patches, while the other group used a placebo.

After three months on estrogen or placebo, the women were tested again. Although many of the tests showed no meaningful differences, the researchers noticed significant changes in one area of complex verbal learning and memory skills. The tester read aloud a shopping list of 16 common words, such as apples, banana or chicken. After hearing the list, the women were required to perform a variety of other brain tests. Twenty minutes later, they were asked to think back and recite the 16-word shopping list.

Women receiving estrogen did far better on the test, making 43% fewer errors after three months on estrogen. The women in the placebo group improved only 9%, according to a May report in the medical journal Menopause. Brain-scan studies of the women also showed that the estrogen users had greater activation in the parts of the brain associated with complex thinking and decision making, says Hadine Joffe, assistant professor of psychiatry at Harvard Medical School and the study's lead author.

One theory about why hormones may help improve a woman's thinking skills has been that they don't actually boost brainpower; instead, they just help a woman sleep by relieving other symptoms like hot flashes. Better sleep is known to improve brain performance.

But in the Harvard study, this theory didn't hold up. The researchers found that a woman's sleeping patterns didn't predict the cognitive improvement. That suggests that the estrogen was doing more than just helping a woman feel and sleep better. It appears that the estrogen was acting directly on the brain, improving mental functioning.

The May Harvard study is in sharp contrast to the findings of the Women's Health Initiative, which suggested women who take hormones have a higher risk for dementia and other problems than non-hormone users. But the WHI dementia studies looked at women who started hormones between the ages of 65 to 79, long past menopause, and many researchers believe the results don't apply to younger women like those studied in the recent Harvard research.

Estrogen's Influence

Complicating the debate about the role of hormones is the fact that scientists still aren't sure exactly how much of an impact menopause really has on the brain in the first place. Some researchers have speculated that the real problem for middle-aged brains is not menopause, but rather the fact that middle-aged women simply live more complicated lives -- with constant multitasking and stress and too little sleep -- than their 20- and 30-year-old counterparts.

We do know that estrogen plays an essential role in brain function and appears to stimulate key brain chemicals linked to cognitive function. And brain-imaging studies consistently show marked declines in brain activity when estrogen is in short supply, notes Barbara Sherwin, professor of psychology and of obstetrics and gynecology at McGill University in Montreal.

But while estrogen clearly plays a biological role in the brain, no one really knows if changes seen on a brain scan mean anything. Sure, the scan lights up differently depending on how much estrogen a woman has in her body, but does it really make a difference in her ability to recall important details during a board meeting or how often she loses her keys?

Surprisingly, several studies have shown that menopause doesn't appear to have a big impact on a woman's memory and thinking ability. One major study of women in Melbourne, Australia, used memory tests to measure differences in cognitive function during various times of life. The study found no detectable change in memory score among menopausal women and no differences among women using hormone drugs.

Subtle Changes

So why do menopausal women feel like they're losing their minds when several studies show they're fine? It may be that the testing methods scientists use to gauge memory and brain function don't detect the subtle changes women themselves notice during menopause.

"If you ask the family members or colleagues of these women, very few would say this person is performing poorly," says Dr. Joffe. "There aren't obvious limitations to the world at large, but the women notice that they're working harder to organize things and are working harder to get to the same goals. These are the women who, once you put them on estrogen, they say, 'Wow, now my brain is back.' "

While nobody thinks women should take hormones to improve their brain health, doctors say women who choose hormones to relieve hot flashes should be reassured by recent news that hormones may help boost thinking skills. And Dr. Joffe notes that everyone, whether it's a woman during menopause or a man juggling multiple responsibilities, can take active steps to improve their daily cognitive function. The main reason people feel like their memory or thinking skills are slipping is usually due to lack of attention, she says. If something is important, take the time to repeat it, write it down and make sure the information is registering in your brain.

"We're pulled in so many directions and distracted by so many things," says Dr. Joffe. "If you stop and take a moment to register the information by writing it down or rehearing it in your brain, everybody would probably do better."