February 9, 2026

expert reaction to study looking at cognitive training and dementia

A study published in Alzheimer’s & Dementia: Translational Research & Clinical Interventions looks at the impact of cognitive training on dementia. 

Dr Susan Kohlhaas, Executive Director of Research and Partnerships at Alzheimer’s Research UK, said:

“This long-term study suggests that a targeted type of brain training, supported by follow-up sessions, may help delay a diagnosis of dementia. With around 20 years of follow-up, it provides a valuable and encouraging contribution to an area where long-term evidence is rare.”

“However, this research does not show that brain training can prevent dementia. Diagnoses were identified through health records rather than specialist clinical testing, so we do not know whether this training changed the underlying diseases that cause dementia or affected specific types of dementia.”

“Further research is now needed to understand how this type of training might work, who could benefit most, and how it fits alongside the strongest evidence we already have for protecting brain health, including staying physically active, managing heart health and keeping socially connected.”

Dr Baptiste Leurent, Associate Professor in Medical Statistics, UCL Department of Statistical Science, UCL, said:

“This long‑term analysis is based on a randomised controlled trial comparing three cognitive training interventions with a no‑training control group. The study claims that one of these exercises is “the first intervention ever to successfully reduce the incidence of Alzheimer’s disease and other forms of dementia.” However, the evidence supporting this claim is questionable.

“The analysis relies on data from a trial conducted 25 years ago, which introduces important limitations.  Only about 75% of the original participants were included, and additional sources of bias are likely, such as missing data and mortality.  The analysis itself is also less rigorous and was not pre‑specified, which would normally be expected in a randomised trial.

“The main limitation is that the only valid randomised comparisons (each of the three training groups versus the control group) did not show significant differences in dementia diagnoses.

“In further analyses, the researchers conducted multiple additional comparisons across six subgroups (each training with or without booster sessions) vs. the control group.  These comparisons are of limited validity because the groups are not comparable.  In the control group, all enrolled participants were eligible, while in the training groups only those who completed a certain number of sessions were included.  Excluded participants from the intervention groups were possibly in poorer health than those who were able to complete the training.

“Furthermore, multiple subgroup comparisons increase the risk of finding a significant result by chance.  Only one borderline significant finding emerged, and no adjustment for multiple testing was made, contrary to standard practice.

“In summary, this study has substantial limitations.  None of the primary analyses found significant differences in dementia risk between the training groups and the control group.  Although one subgroup analysis produced a significant result, this single finding is not generally regarded as strong enough evidence to demonstrate the intervention’s effectiveness.

“Further research is still needed to determine whether cognitive training can reduce the risk of dementia.”

Rachel Richardson, Methods Support Unit Manager, The Cochrane Collaboration, said:

“The ACTIVE study appears to be a well-conducted randomised controlled trial (RCT), but one of its limitations is common to RCTs: the people recruited into the study aren’t necessarily representative of the whole population.  The study excluded people with various existing health conditions including poor vision or hearing.  More people were excluded from participating in the booster training sessions: to be eligible to participate, people had to have completed at least eight out of ten of the initial training sessions.  This again makes the sample less representative: for example, excluding people who fell ill during the first phase of the trial.

“The press release focuses on the ’statistically significant’ result that speed plus booster training reduces the risk of developing dementia by 25%.  It does not however include information on the margins of error around this result which range from a reduction of 41% to one of only 5% – in technical terms the adjusted Hazard Ratio is 0.75, with a confidence interval of 0.59 to 0.95.  So, while statistically significant, the result may not be as impressive as the headline finding.  The other types of training in the ACTIVE study (memory plus booster training and reasoning plus booster training) also showed reductions in the risk of developing dementia, although these did not reach statistical significance.”

‘Impact of cognitive training on claims-based diagnosed dementia over 20 years: evidence from the ACTIVE study’ by Norma B. Co et al. was published in Alzheimer’s & Dementia: Translational Research & Clinical Interventions on Monday 9 February 2026.

DOI: 10.1002/trc2.70197

Declared interests

Dr Susan Kohlhass: “Dr Kohlhaas has no declarations of interest.”

Dr Baptiste Leurent: “No conflict of interest.”

Rachel Richardson: “No interests to declare.”

For all other experts, no reply to our request for DOIs was received.