Can brain training prevent cognitive decline?
The evidence is mixed but there is one standout finding: the ACTIVE trial (Advanced Cognitive Training for Independent and Vital Elderly) — a randomised controlled trial of 2,832 older adults followed for 10 years — found that speed-of-processing training reduced dementia risk by 29%. No other type of brain training showed this effect.
| Intervention | Evidence | Dementia protection? |
|---|---|---|
| Speed-of-processing training (ACTIVE trial) | Strong RCT — 10-year follow-up | 29% risk reduction |
| Memory training (ACTIVE trial) | Strong RCT | No dementia risk reduction |
| Reasoning training (ACTIVE trial) | Strong RCT | No dementia risk reduction |
| Commercial brain training apps | Weak — narrow transfer | No convincing evidence |
| Aerobic exercise | Very strong — multiple RCTs | ~30–40% risk reduction |
| Social engagement | Moderate cohort evidence | Protective — mechanism unclear |
Bottom line: Processing speed training — the type measured by the Processing Speed test and Reaction Time test — has the strongest brain training evidence for dementia prevention. Aerobic exercise still has broader and stronger overall evidence. The two are complementary, not alternatives.
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Quick Answer
The evidence is mixed. The ACTIVE trial (2832 adults, 10-year follow-up) found that speed-of-processing training reduced dementia risk by 29%. Other forms of brain training show narrower transfer. Aerobic exercise has stronger and more consistent evidence for dementia prevention.
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