Large-scale trial reveals only certain types of brain training reduce dementia risk

Two decades of trials suggest that brain-strengthening exercises that involve quick thinking may reduce the risk of dementia, but exercises that involve memorization or reasoning have no effect on the risk.

The discovery could lead researchers to design video games that help users maintain cognitive function as they age, some experts say.

As people age, they are more likely to develop Alzheimer’s disease and other forms of dementia, and these symptoms affect nearly half of people in their 80s and 90s, Northeastern University psychologist Art Kramer, who was not involved in the study, told Live Science. Although there is currently no cure for these disorders, researchers are exploring interventions to reduce the risk of dementia. Some available drugs can help slow cognitive decline in the early stages of the disease, but they are far from a silver bullet.

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Currently, clinical trials that began in the late 1990s point to non-drug interventions that may help prevent dementia.

Weeks of training means years of protection

At the start of the study, 2,021 participants aged 65 and older were enrolled in the long-term randomized controlled trial, the results of which were published on February 9 in the journal Alzheimer’s & Dementia. These participants were divided into four groups. One group performed a speed training exercise in which they divided their attention between two tasks at the same time. The other three groups completed memorization exercises using mnemonics. A reasoning exercise where you find patterns and use them to solve problems. As a point of comparison, the same is true if you do no cognitive training at all.

Participants in the three training groups completed up to 10 60- to 75-minute sessions over 5 to 6 weeks. Some participants received up to four 75-minute “booster” sessions again one to three years later.

Twenty years after the study began, trial runners determined that only speed training was associated with a lower risk of Alzheimer’s disease and dementia. This effect was more pronounced in the booster group.

“If you attended a speed training group and received booster sessions, your risk of being diagnosed with dementia was 25% lower. [by the end of the trial]” said study co-author Marilyn Albert, a neuroscientist at Johns Hopkins University. By comparison, dementia was as common in the other two training groups as in the comparison group, suggesting that memory and reasoning tasks had no protective effect.

The study results raise the question of whether speed-training cognitive exercises, including certain brain-training video games and apps, can help prevent dementia.

Kramer said there are “hundreds of products on the market” that claim to be designed to promote brain health. “When these things become commercialized, sometimes people make claims that go beyond the data, so you always have to worry about that,” he warned. But still, he argued, these games could theoretically achieve effects similar to the speed-training cognitive exercises tested in trials.

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Albert, on the other hand, is hesitant to suggest that video games could replicate the effects seen in the study.

“Processing speed training is not that fun. It’s difficult,” she told Live Science. She argued that the most important element of speed training, which video games may lack, is adaptability. They had to search for objects in the center and edges of the computer screen to find two matches. As performance improves, exercises will update faster and show more objects.

Because this adaptation was not a component of memory or reasoning training, it may explain why it did not lead to a significant reduction in dementia risk, Albert said.

One of the strengths of this trial was the large number of participants, a quarter of whom were from minorities. “People who are black or Hispanic are at higher risk for dementia,” Albert said, arguing that their representation in the study could make the results more generalizable.

The next step is to investigate whether exercise caused specific brain changes that slow neurodegeneration.

“We need to understand the mechanisms, because then we can better design interventions,” Albert said. Kramer proposed tracking MRI scans to see how cognitive training changes the brain anatomy of human participants.

He noted that scientists can train laboratory animals, such as rodents, to perform similar exercises. “And we can also do things that are a little more invasive, like changing the genetic makeup of laboratory mice to understand what genetic factors are involved,” he added.

Meanwhile, Albert noted that scientists already know of other lifestyle factors associated with lower risk of Alzheimer’s disease and other dementias. These include engaging in regular physical activity and maintaining blood pressure within normal limits. Someday, perhaps brain-training exercises will also become a common way to prevent dementia — especially given that this trial required just a few weeks of training to protect participants for 20 years, Albert said.