Effects of COgNitive Training in Community-dwelling Older Adults at High Risk for demENTia (CONTENT): study protocol of two double-blind, randomised, placebo-controlled trials.

introductionDementia contributes to the disease burden worldwide, and people with hypertension or type 2 diabetes are at an elevated risk of developing dementia. It is essential to prevent or delay cognitive decline in people at high risk within the community. Our trials aim to evaluate the effects of adaptive cognitive training on community-dwelling older adults with hypertension or type 2 diabetes but no dementia. METHOD AND ANALYSIS: Two multicentre, double-blind, randomised, placebo-controlled trials, named COgNitive Training in community-dwelling older adults at high risk for demENTia and with Hypertension (CONTENT-Hypertension) and COgNitive Training in community-dwelling older adults at high risk for demENTia and with Diabetes (CONTENT-Diabetes), will be conducted to investigate the effects of adaptive cognitive training on participants aged 60 years or above who have been diagnosed with hypertension or type 2 diabetes but no dementia. Each trial will enrol 120 participants. Participants will be recruited from the local community in Shijingshan and Haidian Districts, Beijing, and allocated to either the intervention or control group using a 1:1 ratio. The intervention group will engage in 12 weeks of adaptive cognitive training, while the control group will receive 12 weeks of placebo cognitive training. A 24-week follow-up assessment will be conducted for all participants to evaluate the persistence of the effects. The primary outcome is the 12-week change in Montreal Cognitive Assessment (MoCA) Basic scores from baseline to the end of the intervention (12 weeks). Secondary outcomes include 6-week and 24-week changes in the MoCA from baseline; 6-week, 12-week and 24-week changes in Trail Making Test-A&B (TMT-A, TMT-B), Digit Symbol Substitution Test, the WHO/University of California at Los Angeles Auditory Verbal Learning Test and Boston Naming Test scores of cognitive functions; 6-week and 12-week changes in Geriatric Depression Scale, Generalised Anxiety Disorder-7 (GAD-7), Pittsburgh Sleep Quality Index and 12-week change in blood pressure (CONTENT-Hypertension) or fasting blood glucose and glycated haemoglobin (CONTENT-Diabetes) from baseline. ETHICS AND DISSEMINATION: This study will adhere to the ethical principles outlined in the Declaration of Helsinki and comply with international standards for Good Clinical Practice. All participants will sign the informed consent at baseline. This study has been approved by the Ethics Committee of Plastic Surgery Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College (approval numbers: 2023-139 and 2024-162). The findings of the trials will be disseminated through publications in peer-reviewed scientific journals and presented at academic conferences. TRIAL REGISTRATION NUMBERS: NCT06512922 and NCT06524388.