]A new review of over 30 randomized research trials finds limited evidence that drugs, herbal products or vitamin supplements help prevent cognitive decline in healthy older adults.
Researchers did find some evidence that cognitive training exercises — or mental exercise — may help prevent cognitive decline.
The review is published in the Canadian Medical Association Journal.
Mild cognitive impairment (cognitive decline that is more than normal for someone of a specific age) affects 10 to 25 percent of people over age 70.
Experts say the annual rate of progression of the decline to dementia (which is cognitive decline in several areas along with some arrested functional ability) is about 10 percent. With an aging population, it is estimated that the prevalence of dementia will double over the next 25 years.
In the current study, Dr. Raza Naqvi, a fellow in geriatric medicine at the University of Toronto, and colleagues reviewed 32 randomized controlled trials to provide the latest evidence for physicians and their patients to help manage cognitive decline.
They failed to discover strong evidence for pharmacologic treatments such as ginkgo, dehydroepiandrosterone (DHEA), vitamins and other substances.
Researchers say that most studies show no beneficial effect from pharmacological therapy whereas estrogen therapy showed an increase in cognitive decline and dementia. Notably, evidence for the benefits of physical exercise is also weak.
Mental exercise, however, showed benefits in the three clinical trials included in the review. This involved computerized training programs or intensive one-on-one personal cognitive training in memory, reasoning or speed of processing. In one trial, participants had significantly improved memory during five-year follow-up periods.
Another study showed an improvement in auditory memory and attention in a group of seniors who participated in a computerized cognitive training program.
“This review provides some evidence to help clinicians and their patients address what strategies might prevent cognitive decline,” writes Naqvi.
“Future studies should address the impact of cognitive training on the prevention of cognitive decline, and we encourage researchers to consider easily accessible tools such as crossword puzzles and Sudoku that have not been rigorously studied.
“The studies in this review that assessed cognitive exercises used exercises that were both labor- and resource-intensive, and thus may not be applicable to most patients.”
Source: Canadian Medical Journal