Decades-long study shows cognitive training reduces dementia risk by 25%

Nearly three thousand people, most of them in their seventies and eighties when the study began in the late 1990s, agreed to spend six weeks doing brain exercises on a computer. Some trained their memory. Others worked on reasoning. A third group focused on speed—processing visual information quickly and making fast decisions as the tasks grew harder. Twenty years later, researchers found something worth noting: the people who trained their processing speed, especially those who came back for additional sessions years into the study, were a quarter less likely to have received a dementia diagnosis.

The ACTIVE study—Advanced Cognitive Training for Independent and Vital Elderly—is one of the longest investigations of its kind. Participants ranged from 65 to 94 years old at enrollment. The initial training ran for 60 to 75 minutes per session over six weeks. Some participants received booster training at the 11-month and 35-month marks. Those who got the maximum benefit underwent as many as 18 sessions spread across three years.

Michael Marsiske, a professor at the University of Florida's Department of Clinical and Health Psychology, led the research team. He told Fox News Digital he was surprised by the results. Earlier findings had shown benefits lasting up to a decade—participants reported fewer difficulties with daily tasks like cooking, taking medication, and managing finances, and they had fewer motor vehicle crashes. But the 20-year data suggested something more durable. "These findings strongly suggest that engagement in cognitive training does no harm and may confer substantial benefit," Marsiske said.

The speed training component appears to work by forcing the brain to adapt. As participants improved, the exercises became progressively harder. Researchers believe this may trigger physical changes in the brain, strengthening connections between neural networks. After five years, participants noticed practical improvements in everyday functioning. After ten years, those trained in reasoning and speed maintained their cognitive gains.

The 25 percent reduction in dementia risk represents one of the first concrete demonstrations that a non-pharmaceutical intervention can lower the incidence of Alzheimer's disease and related dementias. The study was funded by the National Institute on Aging and the National Institute of Nursing Research, and results were published in Alzheimer's & Dementia: Translational Research and Clinical Interventions.

Marsiske is now planning the next phase. He wants to test whether cognitive training works even better when combined with other lifestyle changes—regular physical activity, dietary improvements, and blood pressure management. He's also excited about merging clinical trial data with real-world information from Medicare records, which could reveal patterns invisible in a controlled study alone.

Other researchers have reached similar conclusions through different methods. A recent study in JMIR Serious Games found that certain smartphone games can improve attention and memory. Dr. Daniel Amen, a psychiatrist and founder of Amen Clinics, has emphasized that continuous learning is critical for slowing cognitive aging. He recommends spending 15 minutes daily learning something new—a language, an instrument, a gardening technique—and notes that word games and Sudoku, if pursued with discipline, have evidence behind them.