This study aims to testify multi-domain effects of computerized cognitive training in patients with mild cognitive impairment and mild Alzheimer's disease through multi-dimensional evaluation.

This study aimed to elucidate the neural process enhancement and remodulation in gut microbes resulting from older adults with MCI and mild AD in a randomized controlled trial of a 24-week computerized cognitive training (CCT) program.

After recruitment and baseline assessments, pairs of participants with MCI and mild AD would be randomly allocated into the corresponding subgroup. Participants in CCT group will receive a computerized multidomain cognitive training program (www.66nao.com) and will be required to complete at least 30 minutes of training per day (3 cycle of 5 2-min tasks), 5 days a week for 24 weeks. Adherence to the intervention will be supervised by an independent researcher. The number of training days and training hours per day will be recorded. Patients in control group received treatment as usual (TAU) for 24 weeks. The neuropsychological measures will be performed at baseline, follow-up at 4 weeks, 12 weeks, and 24 weeks; functional Near-Infrared Spectroscopy (fNIRS) data and fecal samples will collected at baseline and 24 weeks.

Inclusion Criteria:

• between 55 and 90 years of age;
• a Clinical Dementia Rating (CDR) score of 0.5 or 1;
• at least three months of stable doses if receiving antidementia medication or mood-stabilizing medication for mild AD participants;
• primary school education and above;
• accompanied by a consistent caregiver (at least 5 days/week);
• informed consent.

Exclusion Criteria:

• factors that might preclude completion of assessments;
• severe psychiatric illness and the use of antidepressants;
• any condition that would preclude completion of training and follow-up tests;
• other disorders that would affect cognition.

With publication of research articles, de-identified data collected for the study, including individual participant data, can be made available to interested parties on reasonable request, and if in line with privacy regulations. Data can be requested at least 18 months after publication of the research articles, with a proposal by sending an e-mail to Dr. Yang Lü.

Data can be requested at least 18 months after publication of the research articles.

With publication of research articles, de-identified data collected for the study, including individual participant data, can be made available to interested parties on reasonable request, and if in line with privacy regulations, with a proposal by sending an e-mail to Dr. Yang Lü.

Since it will not be possible to blind the participants because the experimental and control interventions have to be explained to them and their caregivers before randomization. The single blinding will be applied to researchers who conducted the measurements to minimize the potential assessor biases. Blinding will be also maintained for data management, outcome assessment, and data analysis.