Processing-speed brain training with booster sessions was linked to a lower dementia diagnosis risk over 20 years, according to a long follow-up study.
The findings come from extended tracking of a large randomised controlled trial, where participants were assigned by chance to different training programmes or no intervention.
Researchers linked trial records to US Medicare claims over two decades, allowing dementia diagnoses in routine care to be analysed rather than short-term test scores.
The analysis covered 2,021 participants enrolled in traditional Medicare at baseline and tracked claims from 1999 to 2019 in the Advanced Cognitive Training for Independent and Vital Elderly (ACTIVE) trial.
Participants were assigned to memory training, reasoning training, speed-of-processing training, or a control group that received no intervention.
Speed-of-processing training uses exercises intended to help people take in and respond to information more quickly, often by practising attention across multiple tasks.
Only people in the speed-training group who completed one or more follow-up “booster” sessions showed a lower risk of a diagnosis of Alzheimer’s disease and related dementias, a group of conditions that includes Alzheimer’s.
That group had a 25 per cent lower risk than the control group. Speed training without boosters showed no benefit, and neither memory nor reasoning training produced a statistically significant reduction in dementia risk.
The results suggest cognitive training effects may depend on the format and intensity, with repeated, adaptive exercises appearing to be associated with longer-term benefit.
For clinicians, the findings raise the prospect of structured cognitive exercises as part of prevention strategies in midlife or early older age, particularly for people at higher risk, while indicating that one-off interventions may be insufficient.
Researchers said further studies are needed to confirm the results in broader populations and to better understand why booster sessions appear to matter.