Alzheimer's disease (AD) is the most common form of neurodegenerative disorders leading to dementia. Currently, there has been no effective pharmacologic therapy for this disease. Electroencephalogram-based neurofeedback is considered as a potentially treatment strategy. In this project, the investigators aim to investigate the effectiveness of neurofeedback therapy on cognition for individuals with subjective cognitive decline (SCD). Participants will receive electroencephalogram-based neurofeedback therapy once a day for successive five days. Then, the investigators will evaluate the changes of memory function between baseline and post-therapy visits.

Currently, there has been no effective therapy for Alzheimer's disease (AD). Electroencephalogram-based neurofeedback is now considered as a potentially intervention and may positively affect cognitive function for patients with AD. However, there are few existing studies involving the role of neurofeedback on cognition for subjective cognitive decline (SCD).

Fifty participants with SCD will be recruited in this clinical trial. At baseline, neuropsychological tests are conducted. Participants will receive electroencephalogram-based neurofeedback therapy once a day for successive five days. After that, the investigators will evaluate the changes of memory measures, which is the primary outcome.

Inclusion Criteria:

• 50-79 years old, right-handed and Mandarin-speaking subjects;
• self-experienced persistent decline in cognitive capacity in comparison with a previously normal status and unrelated to an acute event;
• normal age-adjusted, gender-adjusted and education-adjusted performance on standardised cognitive tests;
• concerns (worries) associated with memory complaint;
• failure to meet the criteria for MCI or dementia

Exclusion Criteria:

• a history of stroke;
• major depression (Hamilton Depression Rating Scale score > 24 points);
• other central nervous system diseases that may cause cognitive impairment, such as Parkinson's disease, tumors, encephalitis and epilepsy;
• cognitive impairment caused by traumatic brain injury;
• systemic diseases, such as thyroid dysfunction, syphilis and HIV;
• a history of psychosis or congenital mental growth retardation.

The information of neuropsychological tests will be shared with other researchers.

When summary data are published or starting 6 months after publication.

The information of neuropsychological tests data will be shared.