Mild cognitive impairment (cognitive decline that is more than normal for someone of a specific age) affects 10–25 percent of people over age 70. The annual rate of decline to dementia (which is cognitive decline in several areas along with some functional ability) is about 10 percent. With an aging population, it is estimated that the prevalence of dementia worldwide will escalate sharply.

Raza Naqvi, from University of Toronto (Canada), and colleagues reviewed 32 randomized controlled trials to assess assorted therapies purported to address agerelated cognitive decline. The researchers found that mental exercise 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 5-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. Citing that: “The studies in this review that assessed cognitive exercises used exercises that were both labor-and resource-intensive,” the lead author suggests: “we encourage researchers to consider easily accessible tools such as crossword puzzles and Sudoku.”


  1. Raza Naqvi, Dan Liberman, Jarred Rosenberg, Jillian Alston, Sharon Straus. “Preventing cognitive decline in healthy older adults.” CMAJ, April 15, 2013.