This study aims to examine the effects and potential mechanisms of theta-burst stimulation (TBS) on cognitive function in individuals with mild cognitive impairment (MCI).

The investigators apply the NIA-AA criteria to subtype different endophenotypes of biomarker-defined MCI individuals. This is a prospective, open-label clinical trial, and combined functional neuroimaging study of 18F-FDG-PET to further explore the potential mechanisms. A total of 80 MCI patients will be consecutively recruited and be subjected to iTBS for 5 daily interventions per week for two consecutive weeks. Cognitive evaluation will be performed before and immediately after TBS intervention, and 8 weeks after TBS. Data on functional neuroimaging will be also collected before and after TBS protocol.

Inclusion Criteria:

1. Subjects aged 50-90 year
2. Subjects meet Petersen's criteria for mild cognitive impairment (Petersen, Smith et al. 1999)
3. The CDR of MCI patients can be 0-0.5
4. Amyloid PET should ever be performed

Exclusion Criteria:

1. Any subject has a definite diagnosis of epilepsy or history of seizure attack.
2. Current or past history of clinically significant neurological insults affecting brain structure or function like completed stroke, head injury or brain tumor.
3. Any subject has clinically significant or unstable medical diseases including metabolic, renal,liver, lung or cardiovascular disorders including metabolic, renal, liver, lung or cardiovascular disorders.
4. Any subject has current alcohol or other substances abuse and/ or dependence within the recent one year, or prolonged history of major psychiatric disorder like schizophrenia,bipolar disorder, and previously prolonged substances abuse.
5. Any females who is pregnant or lactating.
6. General MRI, TMS and/or PET exclusion criteria including subjects who had received brain aneurysm surgery, or implanted pacemaker, mechanical valves, cochlear implant or other metal devices/ objects that are not MR compatible in the body.

Withdrawal criteria

1. Complications onset after intervention that affect efficacy and safety judgments.
2. New onset or progression of disease that may affect outcomes.
3. Use of other therapies or drugs during the intervention period to change cognitive functions.
4. Any subjects who are recognized as high risk of adverse effects by principle investigator.