The objective of the study is to evaluate the effectiveness of cognitive training in people with atrial fibrillation and cognitive decline over 12-week cognitive training. Moreover, the investigators will explore whether the training effect can be maintained.

Introduction: Cognitive impairment is a clinical condition characterized of a reduction in memory and/or other cognitive processes that are insufficiently severe to be diagnosed as dementia.The prevalence of dementia among people over 65 years old in China is 5.14% , while the prevalence of mild cognitive impairment is 20.8%. The risk of cognitive impairment and dementia in patients with atrial fibrillation is significantly higher than that those in the same age group, even after adjusted stroke and other common risk factors such as hypertension and diabetes. At present, the effectiveness of cognitive training in patients with atrial fibrillation complicated with cognitive impairment is not clear.

Objectives: The objective of the study is to evaluate whether cognitive training could lead cognitive improvement in patients with cognitive impairment and atrial fibrillation.

Patients and Methods: The proposed study is a double blinded, randomized and controlled trial that will include 200 patients with cognitive impairment and atrial fibrillation. The groups will be randomized to either intervention or active-control group. Both groups will receive computerized cognitive training performed for 30 minutes x 5 times/week over 12 weeks. A neuropsychological assessment will be administered at baseline and week 12 and 24 after the intervention. The structural and functional MRI will be performed at baseline and week 12 after intervention for a sub-study on the effect of cognitive training on brain structure and function.

Inclusion Criteria:

1. Older than 18 years;
2. Completion of 6 or more years of education;
3. Atrial fibrillation confirmed by ECG ;
4. Complain of memory decline within 1 year;
5. The score of any cognitive domain in the processing speed, episodic memory, working memory, and visual-spatial tested by the Basic Cognitive Ability Assessment (BCAT) is 1SD less than the average of the normal population;
6. Agree to receive cognitive function testing and randomization, be able to receive follow-up as required

Exclusion Criteria:

1. Unable to complete the test due to vision, hearing and other problems;
2. Dementia or MMSE Scale ≤ 20;
3. Alcohol abuse or taking drugs that affect cognitive function (antihistamines, antipsychotics);
4. Cannot master the method of cognitive training tool after 2 times, 1 hour each time training instruction;
5. Planned atrial fibrillation ablation within 3 months or received ablation in the last 3 months;
6. CHA2DS2-VASc score ≥ 2 (for female ≥ 3), but refuses anticoagulation or has anticoagulation contraindications;
7. General anaesthesia in the last 3 months;
8. A history of stroke and head injury in the last 6 months;
9. Past history of Parkinson's disease, schizophrenia, and epilepsy;
10. Previous neurosurgery or a history of head tumor;
11. Contraindications for MRI examination: such as metal implantation, claustrophobia, etc.;
12. No family members to assist the patients to do the training course