2022 Alzheimer's Association Research Grant (AARG)

Subjective & Objective Cognitive Decline in Community-Dwelling Older Adults

What types of assessments of early, subtle cognitive decline are most predictive of progression to dementia?

Kelsey Thomas, Ph.D.
University of California, San Diego
La Jolla, CA - United States

Background

Alzheimer’s is a progressive disease, and because of this, scientists are looking for ways to detect and diagnose it at an early stage, before memory loss and other cognitive changes become evident. Neuropsychological testing that evaluates different aspects of cognition including memory, executive function, and language has been used to identify deficits in memory and learning that may indicate an individual is in the early stages of Alzheimer's. However, there is a need for more sensitive measures to detect changes of memory and learning that can be used with other biological markers (biomarkers) to more accurately identify individuals at very early stages of Alzheimer's.

Recent studies have found that individuals who self-report complaints about their memory or other forms of cognition have a greater risk of developing Alzheimer’s in the future. Increasingly, many researchers consider this phenomenon, referred to as subjective cognitive decline, to be part of the earliest phase of the disorder. However, evidence is mixed regarding the relationship between subjective cognitive decline and the risk of progression to dementia. While some research shows a link between subjective cognitive decline and how a person may perform on neuropsychological tests, additional factors may play a role in the progression to dementia, including demographics and physical and mental health.

Research Plan

Dr. Kelsey Thomas and colleagues previously developed a novel way of describing subtle declines in cognition with a method called Objective subtle cognitive decline (Obj-SCD). Previous research suggests that Obj-SCD may be a useful method for identifying early patterns of difficulty or inefficiency in a person’s thinking and may be a sensitive way to measure early changes in cognition. However, this work was conducted in a sample of primarily white and highly educated older adults. There is a need to test this approach in a more racially and demographically diverse sample of older adults. 

To do this, they will study cognitively unimpaired older adults from the Advanced Cognitive Training for Independent and Vital Elderly (ACTIVE) study, a large, multisite study consisting of ten years of data from a racially diverse sample of older adults. The research team will determine whether clinical, health, racial, or other demographic factors are associated with different measures of subjective cognitive decline, including the Obj-SCD. Finally, Dr. Thomas and colleagues will study whether either of these approaches are predictive of future declines in cognition over a ten-year period.

Impact

The results of this project may help develop a more sensitive measure of early changes in cognition. This work may also help shed new light on how these early changes may contribute to dementia risk in diverse populations of older adults.