This study will be conducted to evaluate the rate of Alzheimer's disease conversion differences between high-risk mild cognitive impairment (MCI) and low-risk MCI.

Inclusion Criteria:

• Participant over 55 years old and less than 90 years old
• Participant with subjective memory complaint by informant
• Clinical Dementia Rating (CDR) of 0.5; memory score box must be at least 0.5
• General cognition and functional performance sufficiently preserved such that a diagnosis of Alzheimer's disease cannot be made by the site physician at the time of the screening visit
• Essentially preserved activities of daily living
• Absence of dementia
• Participant with Seoul Neuropsychological Screening Battery-Dementia Version cut-off score between 134.25 and 188.25
• Participants and caregivers who give written authorization to use their personal and health data
• Cognitive decline history within past 6 months from the baseline

Exclusion Criteria:

• Diagnostic evidence of probable Alzheimer's disease consistent with National Institute of Neurological and Communicative Diseases and Stroke-Alzheimer's Disease and Related Disorders Association
• CDR-Global score (CDR-GS) >1
• Participant who has taken memantine, acetylcholinesterase inhibitors, or nootropics prior to participating in this study
• Any significant neurologic disease: other than suspected incipient Alzheimer's disease, such as Parkinson's disease, multi-infarct dementia, Huntington's disease, normal pressure hydrocephalus, brain tumor, progressive supranuclear palsy, seizure disorder, subdural hematoma, multiple sclerosis, or history of significant head trauma followed by persistent neurologic defaults or known structural brain abnormalities
• Neuroimaging: participant with severe subcortical hyperintensities: D3-P3
• Magnetic resonance imaging exclusions: presence of pacemakers, aneurysm clips, artificial heart valves, ear implants, metal fragments or foreign objects in the eyes, skin or body
• Participant who is pregnant, lactating or of childbearing potential (i.e., women must be two years post-menopausal or surgically sterile)

Participants with mild cognitive impairment