The study, which will be presented at the American Academy of Neurology’s 61st Annual Meeting in Seattle, April 25 to May 2, 2009, involved 197 people between the ages of 70 and 89 with mild cognitive impairment, or diagnosed memory loss, and 1,124 people that age with no memory problems.

Both groups answered questions about their daily activities within the past year and in middle age, when they were between 50 to 65 years old.

The study found that during later years, reading books, playing games, participating in computer activities and doing craft activities such as pottery or quilting led to a 30 to 50 per cent decrease in the risk of developing memory loss compared to people who did not do those activities.

People who watched television for less than seven hours a day in later years were 50 per cent less likely to develop memory loss than people who watched for more than seven hours a day.

Volunteers who participated in social activities and read magazines during middle age were about 40 per cent less likely to develop memory loss than those who did not do those activities.

"This study is exciting because it demonstrates that aging does not need to be a passive process. By simply engaging in cognitive exercise, you can protect against future memory loss," said study author Yonas Geda, MD, MSc, a neuropsychiatrist at Mayo Clinic in Rochester, MN, and a member of the American Academy of Neurology.