UC Davis Researchers Awarded $3.3 Million NIH Grant to Study Cultural Differences in Subjective Cognitive Decline
核心洞察
A $3.3 million five-year NIH grant will fund a study tracking approximately 4,000 diverse older adults to examine how cultural differences shape subjective cognitive decline (搜索) (SCD) reporting.
The research aims to determine whether specific types of cognitive complaints—such as memory deficits versus executive function difficulties—predict distinct underlying pathologies like Alzheimer's disease (搜索) or cerebrovascular disease (搜索).
The study addresses critical gaps in SCD research, including lack of racial and socioeconomic diversity, absence of longitudinal data, and the confounding overlap between SCD and depression.
University of California, Davis Professor of Neurology Sarah Tomaszewski Farias has been awarded a $3.3 million five-year grant from The National Institute on Aging to investigate whether cultural differences affect how people perceive and report cognitive changes as they age—a phenomenon known as subjective cognitive decline (搜索) (SCD).
"Subjective cognitive decline (搜索) is when an older person feels their cognition is getting worse, but when we test them using neuropsychological tests, they're still performing within the normal range," explained Tomaszewski Farias, who serves as clinical core leader at the UC Davis Alzheimer's Disease Research Center (搜索).
The study represents a significant shift in how the medical community approaches patients who report cognitive difficulties yet perform normally on standardized tests. Historically, these individuals were often dismissed as the "worried well."
"There was a lot of clinical lore around what we used to call the 'worried well.' These were people that had cognitive complaints but did fine on cognitive testing. It was thought that they were depressed or anxious and often their complaints were dismissed," Tomaszewski Farias said.
However, accumulating evidence has demonstrated that SCD can serve as a risk factor for developing objective cognitive decline, including mild cognitive impairment (搜索) and Alzheimer's dementia.
Addressing Critical Gaps in SCD Research
The new study directly confronts three persistent limitations in the existing SCD literature. First, the overlapping symptoms of SCD and depression can obscure accurate diagnosis, as individuals who are depressed frequently report poor memory. Second, SCD research as a risk factor for Alzheimer's disease (搜索) has been conducted predominantly in highly educated, white populations, leaving significant gaps in understanding how diverse groups experience and express cognitive concerns. Third, most prior studies captured data at a single time point rather than tracking participants longitudinally.
Study Design and Methodology
The research will follow approximately 4,000 participants aged 55 and older, drawing from a longitudinal cohort at the UC Davis Alzheimer's Disease Research Center (搜索) as well as three Kaiser Permanente patient cohorts—Life After 90, KHANDLE, and STAR—led by Professor of Neurology and Public Health Sciences Rachel Whitmer.
Beyond measuring subjective and objective cognitive decline, the study will incorporate brain scans and blood samples to assess biomarkers of Alzheimer's disease (搜索) and cerebrovascular disease (搜索), allowing researchers to validate self-reported cognitive concerns against biological evidence of neuropathology.
Differentiating Complaint Types by Underlying Pathology
A central hypothesis of the study is that different types of subjective cognitive complaints may signal distinct disease processes.
"The term subjective cognitive decline (搜索) doesn't specify the nature or the types of cognitive concerns that people have," Tomaszewski Farias explained. "It may be important to learn if people are reporting mainly memory concerns, or cognitive changes relating to thinking, like executive functions."
She elaborated that predominant memory problems may indicate early Alzheimer's disease (搜索), whereas executive difficulties—including problems with multitasking, working memory, and processing speed—may align more closely with cerebrovascular disease (搜索).
To capture these distinctions, the research team will deploy the Everyday Cognition (ECog) scale, a widely used questionnaire developed by Tomaszewski Farias and UC Davis researchers two decades ago and recently updated. The instrument assesses memory (forgetting recent events), language (difficulty finding words), spatial abilities (navigating one's environment), and executive functions (multitasking and planning daily activities).
"We will look at ways to efficiently identify people who are at increased risk for early Alzheimer's disease (搜索) and other forms of cognitive decline," Tomaszewski Farias said.
Cultural Dimensions and Clinical Implications
The study will examine the extent to which individuals express worry about subjective changes versus attributing them to normal aging. Prior research suggests that some individuals detect internal cognitive shifts that clinical testing cannot yet capture. Current evidence indicates that people may begin noticing these changes approximately 5 to 10 years before a formal clinical diagnosis can be made.
"One size is probably not going to fit all in terms of identifying the red flags of subjective cognitive decline (搜索). It may be very culturally dependent in terms of how people express what they are noticing in their cognitive abilities," Tomaszewski Farias said.
For clinicians, the ultimate goal is to define which subjective complaint types represent genuine red flags warranting closer monitoring and intervention.
"For clinicians, we hope to better figure out or define what are the subjective types of complaint that are a bigger red flag than others," Tomaszewski Farias said.