Just 5 weeks of brain training may protect against dementia for 20 years

The research was funded by the National Institutes of Health (NIH) and is the first randomized clinical trial to track dementia outcomes over two decades in older adults who underwent cognitive training. The participants were part of the Advanced Cognitive Training for Independent and Vital Elderly (ACTIVE) study. Beginning in 1998-99, researchers enrolled 2,802 adults and randomly assigned them to one of three cognitive training groups or to a control group that received no training.

The three interventions focused on memory, reasoning, or speed of processing. Those in the training groups completed up to 10 sessions lasting 60-75 minutes over five to six weeks. About half were also randomly selected to receive as many as four additional booster sessions at 11 and 35 months after the initial program.

20 Year Follow Up Results

Two decades later, researchers analyzed long term outcomes. Among participants who completed speed training and booster sessions, 105 out of 264 (40%) were diagnosed with dementia. In comparison, 239 out of 491 (49%) people in the control group developed dementia. That represents a 25% lower incidence in the speed training group with boosters. Importantly, speed training was the only intervention that showed a statistically significant difference compared to the control group.

To assess dementia diagnoses, investigators reviewed Medicare records from 2,021 participants (72% of the original study) between 1999 and 2019. The follow up group closely reflected the original study population. About three fourths were women, 70% were white, and the average age at the start was 74. Over the 20 year period, roughly three fourths of participants died (at an average age of 84).

Why Dementia Prevention Matters

Dementia involves a decline in thinking and memory severe enough to interfere with daily life and independent living. It is estimated to affect 42% of adults older than age 55 at some point in their lives and costs the United States more than $600 billion annually. Alzheimer's disease accounts for approximately 60%-80% of cases, while vascular dementia represents about 5%-10%. Other forms include Lewy body dementia, frontotemporal dementia, or mixed types.

"Seeing that boosted speed training was linked to lower dementia risk two decades later is remarkable because it suggests that a fairly modest nonpharmacological intervention can have long-term effects," says Marilyn Albert, Ph.D., the corresponding study author and director of the Alzheimer's Disease Research Center at Johns Hopkins Medicine. "Even small delays in the onset of dementia may have a large impact on public health and help reduce rising health care costs."

Albert noted that further research is needed to understand the biological mechanisms behind these results and why memory and reasoning training did not produce the same long term associations.

How Speed Training May Protect the Brain

The new findings build on earlier ACTIVE trial results. Previous analyses showed that cognitive training improved everyday thinking skills for up to five years. After 10 years, all three training types were associated with better daily functioning. Participants who completed speed training had a 29% lower dementia incidence at the 10 year mark compared to the control group. Each booster session was tied to additional reductions in risk.

Researchers believe speed training may have been especially effective because it was adaptive. The program adjusted the level of difficulty based on each person's performance that day. Individuals who performed well progressed to more challenging tasks, while those who needed more time worked at a slower pace. In contrast, the memory and reasoning programs taught the same strategies to everyone.

Speed training also relies on implicit learning, which functions more like building a skill or habit. Memory and reasoning training depend on explicit learning, which involves consciously learning facts and techniques. Scientists know that implicit and explicit learning engage different brain systems, and this distinction may help explain why only speed training was associated with lower dementia risk in this analysis.

"Our findings provide support for the development and refinement of cognitive training interventions for older adults, particularly those that target visual processing and divided attention abilities," says site principal investigator George Rebok, Ph.D., a lifespan developmental psychologist who creates community programs for healthy aging and is a professor emeritus of mental health at the Johns Hopkins Bloomberg School of Public Health. "It is possible that adding this cognitive training to lifestyle change interventions may delay dementia onset, but that remains to be studied."

The authors suggest that speed training could potentially complement other healthy aging strategies that support brain connections, although more research is required to confirm this. Other behaviors linked to lower cognitive decline risk include maintaining heart health by monitoring blood pressure, blood sugar, cholesterol, and body weight, along with regular physical activity.

Additional study authors include Norma B. Coe, Chuxuan Sun and Elizabeth Taggert (University of Pennsylvania), Katherine E. M. Miller and Alden L. Gross (the Johns Hopkins Bloomberg School of Public Health), Richard N. Jones (Brown University), Cynthia Felix (University of Pittsburgh), Michael Marsiske (University of Florida), Karlene K. Ball (University of Alabama at Birmingham) and Sherry L. Willis (University of Washington).

This study was supported by NIH grants from the National Institute on Aging (R01AG056486). The original ACTIVE trial was funded through NIH grants awarded to six field sites and the coordinating center, including Hebrew Senior-Life, Boston (NR04507), the Indiana University School of Medicine (NR04508), The Johns Hopkins University (AG014260), the New England Research Institutes (AG014282), the Pennsylvania State University (AG14263), the University of Alabama at Birmingham (AG14289) and Wayne State University/University of Florida (AG014276).