Cognitive speed training linked to lower dementia incidence up to 20 years later

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Adults age 65 and older who completed five to six weeks of cognitive speed training — in this case, speed of processing training, which helps people quickly find visual information on a computer screen and handle increasingly complex tasks in a shorter time period — and who had follow-up sessions about one to three years later were less likely to be diagnosed with dementia, including Alzheimer’s disease, up to two decades later, according to new findings published today in Alzheimer’s & Dementia: Translational Research and Clinical Interventions.

This National Institutes of Health (NIH)-funded study is the first randomized clinical trial, and only study of its kind, to assess 20-year links with dementia, including Alzheimer’s disease, among adults who participated in the Advanced Cognitive Training for Independent and Vital Elderly (ACTIVE) study. Investigators enrolled 2,802 adults into this study in 1998–99 to assess long-term benefits of participants randomized to three different types of cognitive training — memory, reasoning and speed of processing — in comparison to a control group who received no training. In the three training groups, participants received up to 10 sessions of 60–75 minutes of cognitive training that took place over five to six weeks. Additionally, half of participants were randomized to receive up to four additional cognitive training sessions, or boosters, which took place 11 and 35 months after the initial training. 

In this 20-year follow-up study, investigators found that 105 out of 264 (40%) participants in the speed-training group with boosters were diagnosed with dementia, which was a 25% reduced incidence compared to 239 out of 491 (49%) adults in the control arm. This was the only intervention with a statistically significant, or meaningful, difference compared to the control group.

To reach these findings, investigators reviewed Medicare data from 2,021 participants (72% of the original study) between 1999 and 2019. Characteristics of participants in the follow-up study were similar to the original trial. Three-fourths of participants were women, 70% were white, and the average age was 74 at the start of the study. During the follow-up period, about three-fourths of participants died (at an average age of 84). 

Dementia is characterized as declines in thinking that result in the inability of an individual to live independently or manage on their own on a daily basis. It’s estimated to affect 42% of adults older than age 55 at some point in their life, and costs the U.S. more than $600 billion each year. Alzheimer’s disease, the most common type, accounts for about 60%–80% of dementia cases, while vascular dementia accounts for about 5%–10%. Other types of dementia include Lewy body, frontotemporal or combinations. 

“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 explained that additional studies are needed to understand underlying mechanisms that may help explain these associations and to understand why the reasoning and memory interventions didn’t have the same 20-year associations.

Findings from this 20-year study expand on prior research from the ACTIVE trial, which is the largest study in the U.S. to assess different types of cognitive training in adults. ACTIVE researchers previously found that cognitive training helped participants improve everyday tasks involved with thinking, remembering, reasoning and quickly making decisions for up to five years. All three training arms were also linked to improved outcomes with everyday function 10 years later. Additionally, those who completed speed training had a 29% lower incidence of dementia 10 years later compared to the control group. Each booster session was linked to further risk reductions.

The authors explain that speed training may have been particularly effective because the program was adaptive – it adapted its level of challenge for each participant’s individual performance level that day. People who were faster at the start moved to faster challenges quickly, and people who needed more time started at slower levels. The memory and reasoning programs were not adaptive — everyone in the group learned the same strategies. Additionally, speed training drives implicit learning (more like an unconscious habit or a skill), while memory training and reasoning training drive explicit learning (more like learning facts and strategies). Scientists already know that implicit learning works very differently in the brain than explicit learning, and this may contribute to the results seen with dementia in the current 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 also note that speed training may synergistically support other lifestyle interventions that strengthen neural connections, but more research is needed to understand these interactions and to confirm this. Other activities that have been associated with reduced risk of cognitive decline include taking steps to support cardiovascular health, such as monitoring blood pressure, blood sugar, cholesterol and body weight, and engaging in 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 is funded by NIH grants from the National Institute on Aging (R01AG056486). The original ACTIVE trial was supported by NIH grants to six field sites and the coordinating center. This includes 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).

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