Abstract
Background
KBASE is a prospective cohort study launched at Seoul National University (SNU), South Korea, in 2014 using similar design and methods as the North American Alzheimer’s Disease Neuroimaging Initiative (ADNI). The KBASE cohort consists of well‐characterized participants (420 cognitively normal, 140 mild cognitive impairment, and 90 AD dementia) (Figure 1). It includes systematic longitudinal collection of comprehensive clinical, cognitive and lifestyle data, multimodal neuroimaging, and bio‐specimens for the first six years (“KBASE1”) at a single center. “KBASE2: Korean Brain Aging Study, Longitudinal Endophenotypes and Systems Biology” (NIH Grant U01AG072177) is the second phase of KBASE, launched in collaboration with Indiana University and other institutions. KBASE2 began in 2021, and has similar assessment protocols to the KBASE1. The NIA AD Sequencing Project (ADSP) will perform GWAS and whole genome sequencing (WGS).
Method
Neuropsychological data will be harmonized by the study team and members of the ADSP Phenotype Harmonization Consortium. Comprehensive cognitive data were collected using a battery of standardized tests (Table 1). Harmonization and co‐calibration will enable comparative analyses with cognitive data from similar studies with largely non‐Hispanic white (NHW) cohorts, including the ADNI and AIBL, and ultimately the range of other aging and dementia cohorts including those with underrepresented multi‐ethnic populations. WGS and GWAS data will be harmonized and shared by the ADSP.
Result
Cognitive data harmonization processes are underway and have begun to address the challenges of language and cultural differences. Initial steps include mapping tests and items into an English template. Harmonization and co‐calibration efforts will include identifying appropriate anchor items and accounting for differences in test items that were made to be more culturally and linguistically appropriate. Additional challenges include the wide range of educational attainment as well as gender effects on educational opportunities. A bilingual neuropsychologist who is trained and licensed in the U.S. and a bilingual psychometrics expert are deeply involved in harmonization processes.
Conclusion
Harmonized KBASE cognitive data will be shared with the ADSP and other investigators for use in quantitative phenotype analyses, as well as other pooled, integrative, and comparative studies of other multiethnic, multilingual, U.S., and international cohorts.