Researchers from the University of Virginia in Charlottesville conducted a study of 2,000 healthy adults between the ages of 18 and 60 to assess subtle changes in mental function, including memory, reasoning and perception. Participants were given a variety of standard tests that involved solving puzzles, recalling details from stories and identifying patterns at the beginning of the study, then again at some point over the following seven years.

The researchers found that the capability of abstract reasoning, mental speed and puzzle solving began to decline around the age of 27. Memory was shown to decline at the age of 37. On the positive side, however, participants performed better on tests of vocabulary and general knowledge as they grew older, suggesting that a person's ability to accumulate knowledge actually improves with age. The researchers are currently evaluating the health and lifestyle of participants to determine if any factors might influence age-related changes in cognitive function.

"These patterns suggest that some types of mental flexibility decrease relatively early in adulthood, but that how much knowledge one has, and the effectiveness of integrating it with one's abilities, may increase throughout all of adulthood if there are no pathological diseases," says researcher Timothy A. Salthouse, professor of psychology at the University of Virginia in Charlottesville. He emphasized that young adults do not need to start worrying about their memories and that most people continue to function at a high level, even later in life.

According to the researchers, their findings, which were published in the journal Neurobiology of Aging, provide insight into normal age-related changes in mental function. This may help scientists better understand the process of dementia. "By following individuals over time, we gain insight into cognition changes and may possibly discover ways to alleviate or slow the rate of decline," says Salthouse. "And by better understanding the processes of cognitive impairment, we may become better at predicting the onset of dementias such as Alzheimer's disease."

News Release: Age-related mental decline starts in the late-20s www.news.yahoo.com April 2, 2009