A new analysis from the Advanced Cognitive Training for Independent and Vital Elderly (ACTIVE) study indicates that specific cognitive training focused on processing speed, when reinforced with booster sessions, may reduce the risk of developing Alzheimer’s disease and related dementias (ADRD) over a 20-year period.
The ACTIVE trial, which began in 1998-1999, enrolled 2,802 adults aged 65 or older who lived independently. Participants were randomly assigned to one of four groups: memory training, reasoning training, processing speed training, or a control group with no intervention. The research team linked participant data to Medicare claims spanning from January 1, 1999 through December 31, 2019 to determine dementia diagnoses using established diagnostic codes.
Participants eligible for the study had to demonstrate independence in daily activities and score at least 23 on the Mini-Mental State Examination. Individuals recently treated for cancer or recovering from stroke were excluded.
During two decades of follow-up, nearly half (48.7%) of those in the control group received an ADRD diagnosis. Across all groups, mortality was high—77% died during the study period—reflecting participants’ advanced age at enrollment.
Initial results showed that none of the three cognitive training approaches led to a statistically significant reduction in dementia risk compared with controls after accounting for demographic and health variables. While hazard ratios suggested small reductions in risk (about 12–15%), these differences did not reach statistical significance.
However, a more pronounced effect emerged among participants who underwent processing speed training and also completed booster sessions at months 11 and 35. This subgroup experienced a statistically significant 25% lower risk of being diagnosed with ADRD compared to controls ("Participants assigned to speed-of-processing training who were randomized to receive booster training experienced a statistically significant 25% lower risk of diagnosed ADRD compared with the control group (adjusted hazard ratio 0.75; 95% confidence interval 0.59 to 0.95)."). Those who received initial speed training but not boosters saw no benefit.
Researchers caution that these findings do not establish causality because only participants completing most initial sessions were eligible for boosters—a factor that could introduce selection bias ("Therefore, the results of this study suggest that reinforcement sessions may enhance or sustain training effects, though these findings should not be interpreted as definitively causal..."). Additionally, neither memory nor reasoning-focused interventions reduced dementia risk regardless of booster participation.
The type of cognitive exercise mattered: only attention- and processing-speed-based tasks appeared associated with delayed dementia diagnosis if supported by ongoing reinforcement ("These findings suggest that adaptive, attention-based cognitive exercises may help delay dementia diagnosis in older adults.").
Study authors note several limitations: diagnoses relied on Medicare claims rather than direct clinical assessment; individuals enrolled in Medicare Advantage plans were excluded; and misclassification is possible due to coding practices or healthcare utilization patterns.
Despite these caveats, researchers say their findings support further exploration into structured mental exercises as part of strategies aimed at extending healthy aging and independence among older adults.
