The KBASE2 is the second phase of the KBASE project, which consists of roll-over participants from the first phase of the KBASE as well as newly enrolled participants with varying degrees of cognitive functions (e.g. individuals with normal cognition, mild cognitive impairment, or AD dementia). In addition to the aims of the first phase of the KBASE, the KBASE2 will focus on new data collection and integrative analysis of the rich structural, functional, and molecular neuroimaging data in relation to whole genome sequencing and other -omics. Network analysis of disruption in brain connectivity in relation to clinical status and AD biomarker profiles also will be conducted.

The Korean Brain Aging Study for the Early Diagnosis and Prediction of AD (KBASE) is a comprehensive prospective cohort study launched at Seoul National University (SNU) in 2014 using similar methods to the North American AD Neuroimaging Initiative (ADNI). KBASE includes well-characterized participants with normal cognition (CN), mild cognitive impairment (MCI) and AD dementia. Clinical/cognitive and lifestyle data, multimodal neuroimaging (structural MRI, MR angiography, diffusion tensor imaging, and resting-state fMRI, as well as amyloid, tau and FDG-PET, and bio-specimens were longitudinally collected during the past five years.

The KBASE2, the second phase of the KBASE project, will focus on new data collection and integrative analysis of the rich structural, functional, and molecular neuroimaging data in relation to WGS and other -omics. Network analysis of disruption in brain connectivity in relation to clinical status and AD biomarker profiles in KBASE will be related back to the NIA AD Sequencing Project (ADSP) multi-ethnic dataset (N>20,000) results. Amyloid, tau, neurodegeneration, and cerebrovascular integrity (A/T/N/V) neuroimaging biomarkers will be investigated cross-sectionally and longitudinally. Findings will be contrasted with and validated in independent cohorts, including ADNI and the Indiana Memory and Aging Study (IMAS), which both have similar genetic and deep longitudinal endophenotype data. The overarching premise is that 1) development of precision medicine for ADRD requires systematic multi-modal biomarker collection in diverse cohorts during early at-risk stages of disease to identify diagnostic, prognostic and therapeutic targets, and 2) sophisticated analytic strategies are required to address the complexity of multimodal data, heterogeneity, and diverse participant cohorts. Integrative longitudinal analysis of genetic and -omics networks with structural and functional brain networks in this Asian cohort will yield new targets related to A/T/N/V pathology and other pathways

In KBASE2 projects, the KBASE team at Seoul National University (SNU) and AD research team at Indiana University (ADNI Genetics Core, Indiana ADRC, IU Network Science Institute) will closely collaborate with the ADSP and its multi-institutional working groups, and the Universities of Pennsylvania and Southern California. Whole genome sequences (WGS) will be ADSP-harmonized by the NIA Genomic Center for AD (GCAD) and shared via NIAGADS (both UPenn). The Laboratory of Neuroimaging (LONI; USC) will support imaging and related data sharing.

Participants will be classified as either Alzheimer's disease(AD) group, mild cognitive impairment(MCI) group, elderly normal controls or young normal controls. Specific inclusion criteria for each group is described below.

Inclusion Criteria:

[Inclusion criteria: AD]

• Age : 55 - 90
• Clinical Dementia Rating (CDR)=0.5 or 1
• Diagnostic and Statistical Manual-IV(DSM-IV) criteria for dementia
• National Institute of Aging and the Alzheimer's Association (NIA-AA) Probable AD dementia
• Study partner or caregiver to accompany patient to all scheduled visits
• Written informed consent

[Inclusion criteria: MCI (amnestic)]

• Age : 55 - 90
• Clinical Dementia Rating (CDR)=0.5
• Concern regarding a change in cognition (obtained from the subject, from an informant who knows the subject, or from a skilled clinician observing the subject)
• Lower performance in any cognitive domain that is greater than would be expected for the subject's age and educational background
• Preservation of independence in functional abilities
• Study partner or caregiver to accompany subject to all scheduled visits
• Written informed consent

[Inclusion criteria: Elderly normal controls]

• Age : 55 - 90
• Clinical Dementia Rating (CDR)=0
• Those with contactable Informant
• Written informed consent

[Inclusion criteria: Young normal controls]

• Age : 20 - 54
• Clinical Dementia Rating (CDR)=0
• Written informed consent

Exclusion Criteria:

[Exclusion criteria: general]

• Past history or presence of major psychiatric illness (e.g. schizophrenia, bipolar disorder, alcohol/substance abuse or dependence, delirium)
• Significant neurologic or medical condition that can influence the mental state
• Contraindications for MRI scan (e.g. pacemaker, claustrophobia)
• Illiteracy
• Significant visual or hearing difficulty
• Taking investigational drug
• In pregnancy or breast-feeding

Young and elderly normal controls: community-based population AD and MCI: clinic or community-based population