It turns out that if you think you are on your game, then you are. The research from the Seattle Midlife Women’s Health Study showed that 60% of women in the menopausal transition report decreased memory function over the past few years, including forgetfulness. The Decision at Menopause study was also relied upon for some of their findings. Yet their studies also revealed an effect on perception of your function as it actually correlates to your memory function. Positive attitude again comes through as an important indicator of success. Of course it's easier to have a positive attitude if your gyno confirms that is warranted, so don't skip the yearly visits, she has things to say to your about how to keep sharp and keeping positive!
For other sources of menopause information, seek resources at menopause.org.