A long-running US clinical trial has found that a simple brain-training exercise can reduce the risk of developing dementia by 25 percent, offering one of the strongest pieces of evidence to date that cognitive decline may be preventable. Researchers said the finding emerged from a randomised controlled trial, widely regarded as the gold standard in medical research, marking the first time suc a study has demonstrated a clear intervention that significantly lowers dementia risk.
“For the first time, this is a gold-standard study that’s given us an idea of what we can do to reduce risk for developing dementia,” said study co-author Marilyn Albert of Johns Hopkins University in the United States.
The researchers stressed that the results do not validate the wide range of commercial brain-training games and apps on the market, many of which lack strong scientific backing. Only one specific type of training tested in the study showed a measurable benefit.
The trial, known as ACTIVE, began in the late 1990s and involved more than 2,800 participants aged 65 and older. Volunteers were randomly assigned to one of three types of cognitive training, speed, memory or reasoning, or placed in a control group.
Participants completed hour-long training sessions twice a week for five weeks, followed by booster sessions one and three years later. In total, the training lasted fewer than 24 hours.
Follow-up assessments conducted after five, 10 and 20 years showed that speed-based training consistently delivered the strongest results. Albert noted that this approach was “disproportionately beneficial” over time.
After two decades, Medicare records revealed that participants who completed the speed-training exercises and booster sessions had a 25 percent lower risk of developing dementia. The other two training methods did not produce statistically significant effects.
The speed-training task, known as “Double Decision,” involves rapidly identifying cars and road signs that appear in different parts of a computer screen. Researchers believe the training may improve brain connectivity, although the precise mechanism remains unclear.
“We assume that this training affected something about connectivity in the brain,” Albert said, adding that the adaptive nature of the exercise, which adjusts to a person’s abilities, may be key to its success.
Albert described the findings as “extraordinarily important,” noting that cutting dementia rates by a quarter could save the United States an estimated $100 billion in care costs. Dementia affects about 57 million people worldwide and is the seventh leading cause of death globally, according to the World Health Organization. The study was published in Alzheimer’s and Dementia: Translational Research & Clinical Research.
