Controversial Brain Training Study Shows Decades-Long Impact on Dementia Risk

A landmark decades-long randomized controlled trial has delivered compelling evidence that a specific type of cognitive training can significantly reduce the risk of dementia in older adults, with results published on February 9, 2026, in the journal Alzheimer’s & Dementia. The findings, which indicate a 25 percent lower risk of dementia diagnosis two decades after initial training, directly address years of scientific debate surrounding the efficacy of brain exercises in preventing cognitive decline.

The study, which began enrolling participants in the late 1990s, tracked the cognitive health of over 2,800 healthy older adults aged 65 or older. Participants were divided into groups, with some receiving specific cognitive training and others serving as controls. The training regimen involved computer-based tests designed to enhance the speed of cognitive processing. These exercises required participants to rapidly identify visual information, managing increasingly complex stimuli within shrinking timeframes and responding quickly while dividing their attention across multiple task elements, according to Yahoo News.

Long-Term Trial Reveals Dementia Risk Reduction

The initial phase of the training consisted of hour-long sessions, twice a week, over a period of five weeks. This was followed by booster sessions one to three years later. AARP reported that participants who completed 14 to 22 hours of this specific type of brain training exhibited a 25 percent lower risk of being diagnosed with dementia 20 years later, compared to those who did not receive the training. This long-term follow-up, conducted after five, 10, and 20 years, underscored the disproportionate benefits of speed training.

Researchers explained that while memory and reasoning training typically engage ‘declarative memory,’ the speed training primarily involved ‘procedural memory.’ The study’s conclusion highlighted that “Cognitive training involving speed of cognitive processing has the potential to delay the diagnosis of Alzheimer’s disease and related dementias (ADRD).” This randomized controlled trial is considered a gold standard in medical research, lending significant weight to its findings.

Addressing Years of Brain Training Debate

The field of brain training as a preventative measure for dementia has been mired in controversy for years. In 2014, more than 70 scientists issued an open letter asserting a lack of conclusive evidence for the dementia-protecting benefits of brain training. However, this was quickly countered by another open letter from 100 scientists who challenged these claims. The latest results from this decades-long trial provide some of the most robust evidence to date in favor of cognitive training’s long-term benefits.

Dr. Andrew Budson, a neurologist and associate director of the Alzheimer’s Disease Research Center at Boston University, expressed a cautious optimism, stating, “It’s really quite rare for any computerized-game brain training study to show positive results — and to show effects on a diagnosis of Alzheimer’s disease 20 years later.” His remarks, reported by AARP, emphasize the unique nature of these findings in a field often characterized by skepticism.

Future Outlook for Cognitive Health

Despite the promising outcomes, researchers and experts still call for further investigation. Dr. Kohlhaas, whose affiliation was not specified in the provided sources, cited a limitation of the study: diagnoses were identified through health records rather than specialist clinical testing. She noted, “So we do not know whether this training changed the underlying diseases that cause dementia or affected specific types of dementia.” Similarly, Baptiste Leurent, professor of medical statistics at University College London, reiterated that “Further research is still needed to determine whether cognitive training can reduce the risk of dementia.”

Nevertheless, these new findings offer a significant step forward, providing concrete, long-term data that could reshape perspectives on cognitive interventions for aging populations. While more research is undoubtedly needed to understand the precise mechanisms and broader applicability, the study introduces a compelling argument for incorporating specific speed-based cognitive training into strategies aimed at maintaining brain health and delaying the onset of dementia.