Processing-speed brain exercise may cut dementia risk by 25%

A decades-long randomised trial of more than 2,800 adults found that processing-speed cognitive training was associated with an about 25% lower rate of diagnosed dementia over roughly 20 years, while memory and reasoning training did not show a clear reduction.

A long-running randomised trial reports that a specific mental exercise focused on processing speed was linked with a lower rate of dementia diagnoses over about 20 years. The trial began in the late 1990s and enrolled more than 2,800 people aged 65 or older. Participants were randomly assigned to processing-speed training, memory training, reasoning training, or a control group and received an initial course plus occasional booster sessions. Brain training as a dementia-prevention approach has been debated, and independent experts have advised careful interpretation of these new results. Key facts: - Processing-speed training was associated with an approximately 25% lower risk of diagnosed Alzheimer’s disease and related dementias (ADRD) over follow-up periods up to 20 years. - Memory and reasoning training did not show statistically significant reductions in dementia risk in this study. - Diagnoses were identified through health records rather than specialist clinical testing, and the trial excluded people with poor vision or hearing, which are noted limitations. - Participants in the speed group who did not complete the initial training or booster sessions did not show a significantly lower risk of diagnosed ADRD. Summary: The study offers long-term data suggesting processing-speed exercises may be linked with a lower rate or delayed diagnosis of dementia, while other training types did not show the same effect. Independent researchers highlighted limitations in diagnosis methods and sample representativeness and said further research is needed to clarify how the training might work and who could benefit most.