A groundbreaking study, funded by the National Institutes of Health (NIH), marks the first randomized clinical trial to observe dementia outcomes over two decades among older adults who participated in cognitive training. The research involved individuals from the Advanced Cognitive Training for Independent and Vital Elderly (ACTIVE) study, which began in 1998-99, enrolling 2,802 adults who were divided into three cognitive training groups and a control group that received no training.
The training sessions were designed to enhance memory, reasoning, or processing speed. Participants in the training groups engaged in up to 10 sessions, each lasting between 60 to 75 minutes, spread over five to six weeks. Additionally, around half of the participants were randomly chosen to partake in up to four extra booster sessions at 11 and 35 months following the initial training.
Long-Term Findings After 20 Years
After two decades, the researchers evaluated the long-term outcomes. Among those who completed speed training along with booster sessions, only 105 out of 264 (40%) were diagnosed with dementia. This contrasts with 239 out of 491 (49%) individuals in the control group, indicating a 25% reduction in dementia incidence for the speed training group with boosters. Notably, speed training was the only intervention that demonstrated a statistically significant difference compared to the control group.
To determine dementia diagnoses, researchers examined Medicare records from 2,021 participants (72% of the original study) between 1999 and 2019. The follow-up group closely mirrored the original participants, with approximately three-fourths being women, 70% identifying as white, and an average starting age of 74. Over the 20-year span, about three-fourths of participants passed away, averaging 84 years of age.
The Importance of Dementia Prevention
Dementia leads to significant declines in thinking and memory, severely affecting daily life and independence. It is estimated that 42% of adults over 55 will experience dementia at some point, costing the U.S. economy over $600 billion annually. Alzheimer's disease constitutes approximately 60%-80% of dementia cases, while vascular dementia accounts for about 5%-10%.
"The link between enhanced speed training and reduced dementia risk over two decades is astonishing, indicating that a relatively simple non-pharmacological approach can yield lasting benefits," remarks Marilyn Albert, Ph.D., the lead author of the study and director of the Alzheimer's Disease Research Center at Johns Hopkins Medicine. "Even minor delays in dementia onset can significantly impact public health and help alleviate growing healthcare expenses."
Albert emphasizes the need for further research to uncover the biological mechanisms behind these findings and why memory and reasoning training did not yield similar long-term benefits.
How Speed Training Protects the Brain
The new results build upon earlier findings from the ACTIVE trial. Previous studies indicated that cognitive training could enhance everyday thinking skills for up to five years. After ten years, all three training types were associated with improved daily functioning. Participants who underwent speed training exhibited a 29% lower incidence of dementia at the ten-year mark compared to the control group, with each booster session correlating with further risk reductions.
Researchers propose that speed training was particularly effective due to its adaptive nature, adjusting difficulty levels based on individual performance. Those who excelled progressed to more challenging tasks, while others were allowed to proceed at a more comfortable pace. In contrast, memory and reasoning programs applied uniform strategies to all participants.
Speed training also promotes implicit learning, akin to skill or habit development, whereas memory and reasoning training relies on explicit learning, which involves conscious acquisition of facts and techniques. This distinction may clarify why only speed training was linked to lower dementia risk in this study.
"Our findings advocate for the enhancement of cognitive training programs for older adults, especially those focusing on visual processing and divided attention," states George Rebok, Ph.D., the principal investigator and a professor emeritus of mental health at the Johns Hopkins Bloomberg School of Public Health. "Incorporating this cognitive training into lifestyle interventions may delay the onset of dementia, though this requires further investigation."
The authors suggest that speed training could complement other healthy aging strategies that foster brain connectivity, although additional research is essential to validate this. Other behaviors associated with reduced cognitive decline risk include maintaining cardiovascular health through monitoring blood pressure, blood sugar, cholesterol, and body weight, along with engaging in regular physical activity.
This study had contributions from various authors, including Norma B. Coe, Chuxuan Sun, and Elizabeth Taggert from the University of Pennsylvania, among others. The research received support from NIH grants from the National Institute on Aging.