This form of mental exercise may cut dementia risk for decades

A new study suggests that engaging in a particular form of brain training may cut dementia risk for decades. spawns/Getty Images hide caption

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A little brain training today may help stave off Alzheimer's disease and other forms of dementia for at least 20 years.

That's the conclusion of a study of older adults who participated in a cognitive exercise experiment in the 1990s that was designed to increase the brain's processing speed.

The federally funded study of 2,802 people found that those who did eight to 10 roughly hourlong sessions of cognitive speed training, as well as at least one booster session, were about 25% less likely to be diagnosed with dementia over the next two decades.

"We now have a gold-standard study that tells us that there is something we can do to reduce our risk for dementia," says Marilyn Albert, an author of the study and a professor of neurology at Johns Hopkins University School of Medicine.

"It's super-exciting to see that these effects are still holding 20 years out," says Jennifer O'Brien, an associate professor of psychology at the University of South Florida who was not involved in the research.

The study appears in the journal Alzheimer's & Dementia: Translational Research & Clinical Interventions. 

"Taking care of my neurons"

The result is good news for people like George Kovach, 74, who started doing cognitive speed training a decade ago.

"I was interested in taking care of my neurons," says Kovach, who lives in Vienna, Virginia.

So Kovach signed up for an online program called BrainHQ, which includes the same speed exercises used in the study.

"I think I've done over 1,300 [sessions] of BrainHQ exercises," Kovach says.

"These things are hard, but you do get better at it," he says. "I look at it like doing sit-ups."

Kovach also does sit-ups, as well as high-intensity aerobic workouts on his bike — an activity shown to promote healthy brain aging. And he follows a heart-healthy diet.

Thanks to all these factors, he says, his brain is working better than ever.

Building a faster brain

The new study used Medicare records to see what happened to participants in the ACTIVE study, a randomized controlled trial designed to compare various forms of brain training. It was funded by the National Institutes of Health and got underway in 1998.

ACTIVE included exercises designed to boost memory and reasoning, as well as speed. But only the people who did speed training were less likely to be diagnosed with dementia.

That could be because this form of brain training appears to trigger something called implicit learning, which involves acquiring unconscious or automatic skills, like swimming or tying a shoelace.

"We know that implicit learning operates differently in the brain and has more long-lasting effects," Albert says.

"You can learn to ride a bike in about 10 hours of training," says Henry Mahncke, a neuroscientist and the CEO of BrainHQ's parent company, Posit Science. And even if you don't practice for the next 20 years, he says, you [will] still have "a bike-riding brain."

BrainHQ's speed-training exercise has users watch a computer screen. At some point, a car or a truck flashes in the center and a road sign shows up on the periphery. The challenge is to recall whether the image was a car or a truck and then to click on the area where the road sign appeared.

"If you had all day to look at that, anyone could figure it out," Mahncke says. "But it doesn't give you all day. It shows the image on the screen to you very quickly and then it goes away."

Also, as a user gets better, the exercise adds more and more visual distractions.

Is more training better?

Finding that a modest amount of training had a measurable impact on dementia decades later is "astonishing," Albert says.

But it also raises an obvious question, Mahncke says: "What if people had kept doing the speed training?"

An ongoing study funded by the National Institutes of Health may help answer that question. It's called the Preventing Alzheimer's with Cognitive Training (PACT) study, and it has enrolled about 7,500 people age 65 and older.

Instead of 10 or more hours of training, as in the ACTIVE study, PACT asks participants to complete 45 sessions over several years.

Most scientists believe this increased dose of training will provide even greater benefits. But people shouldn't feel they need to become mental marathoners to protect their brains, O'Brien says.

The results with ACTIVE suggest that just 10 hours of training, with some booster sessions, can make a difference, she says. So some people may want to do that much and then stop.

The benefits of more training will become clearer when the first results from the PACT study arrive, O'Brien says, probably in 2028.