subjective cognitive decline (SCD) refers to individuals who subjectively think that they have a sustained decline in memory or cognitive function compared with their previous normal state, but the objective neuropsychological test is within the normal range. Western research results show that SCD people may be in the preclinical stage of Alzheimer's disease (AD), and increase the risk of cognitive decline and progression to mild cognitive impairment and AD dementia in the future. At the same time, the results of research in western countries show that specific SCD populations, such as worry about their own cognitive decline, and additional factors such as onset within 5 years (SCD-plus) can increase the proportion of pre-clinical AD in SCD populations. Therefore, SCD provides an important window period for secondary prevention of AD. However, the research paradigm of existing SCD research is not uniform, and most studies are based on Western population data. Different languages and sociocultural backgrounds may affect the manifestation and enrollment diagnosis of SCD. Therefore, cross-cultural/ethnic studies of SCD are an important topic.
