A total of 249 participants with Alzheimer's continuum (125 participants with AD dementia, 103 participants with MCI due to AD, and 21 participants with preclinical AD) were collected from the memory disorder clinic in the department of neurology at Samsung Medical Center in Seoul, Korea between September 2013 and March 2018. Each participant received neuropsychological battery, high-resolution T1-weighted magnetic resonance imaging (MRI) scan, and 18F-flutemetamol positron emission tomography (PET) to assess amyloid-β (Aβ) deposition. The time interval between assessments was less than 6 months. According to the National Institute on Aging-Alzheimer's Association criteria,11 (link)12 (link)13 (link) Aβ (+) cognitive normal or subjective memory concerns, Aβ (+) MCI, and Aβ (+) clinically diagnosed AD type dementia were defined as preclinical AD, MCI due to AD, and AD dementia, respectively. We excluded secondary causes of cognitive impairment by laboratory tests, including complete blood count, blood chemistry, vitamin B12/folate, syphilis serology, and thyroid function tests. All participants had no significant whiter matter hyperintensities (cap or band <5 mm and the longest diameter of deep white matter lesion <10 mm), cerebral infarctions, intracranial hemorrhages, brain tumors, hydrocephalus, or other structure lesions.
Our study protocol was approved by the Institutional Review Board (IRB) of Samsung Medical Center (IRB file No. 2013-07-073). All participants provided informed consent for research according to the guidelines outlined in the Declaration of Helsinki.