Creator: Help Dementia Editorial Team
Published: 2026-04-05T06:22:53

Reviewed by the Help Dementia Editorial Team — our editors review every article for accuracy against guidance from the National Institute on Aging, the Alzheimer’s Association, and peer-reviewed sources.

Brain training sits at the center of this dementia and brain health question.

A brain training game called “double decision,” originally designed by researchers Karlene Ball and Daniel Roenker, has become the centerpiece of some of the most compelling long-term dementia prevention research in medical history. The Preventing Alzheimer’s with Cognitive Training (PACT) study—built on decades of work by the same researchers—recently received an additional $2.8 million in federal funding from the National Institute on Aging, part of the NIH.

The reason for continued investment is straightforward: participants who completed just 5 weeks of this speed-training exercise showed a 25% lower risk of developing Alzheimer’s disease and other dementias, with that protective effect lasting up to 20 years after the training ended. Unlike the countless brain games that claim to sharpen memory or solve puzzles, this intervention is the first of its kind to demonstrate sustained, measurable protection against actual dementia diagnosis in long-term clinical studies. This article explores what the research actually shows, how the training works, and what makes it different from other cognitive exercises available today.

What Is the Double Decision Game and Who Designed It?
The Research That Changed Dementia Prevention
The PACT Study and Modern Expansion
How to Access the Training: BrainHQ and Beyond
Why Speed of Processing Matters for Dementia Prevention
Comparing Speed Training to Other Brain Training Claims
The Broader Implications for Dementia Prevention
Conclusion

What Is the Double Decision Game and Who Designed It?

The “double decision” exercise was originally created by psychologists Karlene Ball and Daniel Roenker, who first developed it using NIH grants in the 1980s. The game trains the speed at which your brain processes visual information—what researchers call “speed of processing.” In the exercise, players watch a computer screen where cars and directional arrows appear briefly, and they must respond as quickly as possible to identify the objects and their movements. The difficulty ramps up progressively, forcing the brain to work faster while maintaining accuracy. This approach differs fundamentally from what most people think of as “brain training.” Memory games ask you to recall information.

Puzzle games challenge your logical reasoning. Speed-of-processing training does something else: it teaches your brain to see, process, and react faster to the world around you. This turns out to matter for dementia prevention in ways that puzzle games, despite decades of marketing, have never demonstrated in large clinical trials. The training was delivered through computerized sessions, with participants in the original research completing up to 23 hours of training over a 3-year period.

What Is the Double Decision Game and Who Designed It?

The Research That Changed Dementia Prevention

The foundation for this work comes from the ACTIVE trial (Advanced cognitive Training for Independent and Vital Elderly), which enrolled nearly 3,000 participants ages 65 and older. That study, published over two decades ago, showed that cognitive training could improve specific cognitive abilities immediately after training. But the real breakthrough came much later: researchers continued following participants for years, watching whether training had any effect on actual dementia diagnosis.

The results, published in February 2026, showed that those who received speed-of-processing training had a 25% lower risk of Alzheimer’s and other types of dementia compared to a control group—and this protection held steady for up to 20 years. However, there’s an important caveat: not all types of cognitive training showed this effect. Memory training and reasoning training, also tested in the ACTIVE trial, did not demonstrate the same long-term protection against dementia diagnosis. This specificity is crucial—it suggests that speed of processing might address a particular vulnerability in cognitive aging that other interventions miss.

The PACT Study and Modern Expansion

Recognizing the significance of these findings, the NIH funded the PACT study, launched at 10 sites across the southeastern United States, including Duke University, Clemson University, and the University of Florida. PACT is the largest clinical trial of cognitive training ever conducted, enrolling 7,600 older adults. The trial represents a total federal investment exceeding $50 million, with the March 2026 award of an additional $2.8 million specifically supporting expansion and longer-term follow-up of participants.

This scale matters. The original ACTIVE trial, while carefully designed, involved a smaller cohort. PACT is designed to confirm those findings across a much larger, more diverse population and to explore whether the protective effects extend beyond what was observed in earlier work. With 7,600 participants, PACT can also examine whether the training works equally well for different demographic groups, different levels of education, and people with varying baseline cognitive abilities.

How to Access the Training: BrainHQ and Beyond

The double decision exercise is now available to the public through an online platform called BrainHQ, a subscription-based brain training service. BrainHQ offers the speed-of-processing training along with other cognitive exercises. The platform delivers the training in shorter sessions than the clinical trial used—typically 15 to 20 minutes per session—making it more accessible to people who want to try it outside of a research setting.

However, there’s an important distinction to understand: the specific evidence for dementia prevention comes from the intensive training protocol used in the clinical trials, where people completed multiple hours of training over several weeks. If you use BrainHQ, you’re using the same underlying training method, but you’re doing so at your own pace and without the structure of a clinical trial. The research shows that the training itself works; whether using it casually produces the same protection remains an open question. For people interested in trying this approach, BrainHQ requires a monthly subscription, making it a financial commitment beyond what many other free brain game apps offer.

Why Speed of Processing Matters for Dementia Prevention

Cognitive aging affects different mental abilities in different ways. Memory typically declines first and most obviously. But speed of processing—the brain’s ability to quickly take in and respond to information—is also a core component of cognitive function that deteriorates with age. Some researchers hypothesize that maintaining speed of processing might protect against dementia by maintaining the brain’s overall capacity for efficient processing and by potentially supporting the connections between different brain regions.

The protective effect isn’t instantaneous or automatic. The training in the clinical trials took time—people trained for weeks and completed multiple hours of exercises. And while 25% reduction in dementia risk is significant, it’s not a guarantee. People who completed the training still developed dementia; it just happened less frequently and, on average, several years later than in control groups. Additionally, the research involved largely older, cognitively healthy adults in the original ACTIVE trial; whether the same protection applies to people with mild cognitive impairment or early dementia remains unclear.

Why Speed of Processing Matters for Dementia Prevention

Comparing Speed Training to Other Brain Training Claims

The brain training market is crowded with apps and games claiming cognitive benefits. Most of these claims rest on short-term studies showing that people get better at the specific game they’re playing—not surprising, since practice at any task improves performance at that task. What’s rare is long-term evidence that training on a specific game translates to real-world cognitive benefits or protection against actual disease.

The speed-of-processing training stands out because the evidence comes from a large, federally funded clinical trial with decades of follow-up. This doesn’t mean other brain games are useless or ineffective—puzzle games and memory games may offer genuine cognitive stimulation and engagement. But if your goal is specifically to reduce dementia risk, the evidence base for speed training is substantially stronger than for most alternatives currently available.

The Broader Implications for Dementia Prevention

The PACT study and the evidence it’s building matter beyond just brain training. For decades, dementia has been approached primarily as a disease to be treated after symptoms appear. Speed-of-processing training is rare in the field because it’s one of the first interventions shown to successfully reduce dementia risk through a mechanism that doesn’t require medication or invasive procedures.

It’s also potentially scalable—if an online platform can deliver similar results to in-person training, it could reach millions of people, making it one of the few dementia prevention strategies accessible to people regardless of geography or income level. The ongoing PACT trial may answer critical questions about who benefits most, whether online delivery works as well as in-person training, and whether shorter, maintenance-level training can sustain protection over time. As research continues, what was once an obscure experimental exercise tested in a few dozen older adults may become a standard recommendation in dementia prevention, alongside diet, exercise, and cognitive engagement.

Conclusion

The brain training game known as “double decision,” designed by researchers Karlene Ball and Daniel Roenker, represents a rare bright spot in dementia prevention research: an intervention with genuine long-term clinical trial evidence showing that it reduces the risk of Alzheimer’s disease by 25% over decades. The ongoing PACT study, with its $50 million in federal funding and 7,600 participants, is expanding what we know about who benefits and how the training can be delivered in modern, accessible ways through platforms like BrainHQ.

If you’re interested in dementia prevention, the evidence suggests that speed-of-processing training is worth considering as part of a broader approach that also includes physical exercise, cognitive engagement, social connection, and cardiovascular health. The training requires time and, through BrainHQ, a financial commitment, but unlike many brain training products on the market, it’s backed by the kind of rigorous long-term evidence that should give you confidence in its potential benefit.