Clinical Progression of Baseline Risk States for Mild Cognitive Impairment

Background: This memory-clinic study joins efforts to study earliest clinical signs and symptoms of Alzheimer's disease and related dementias: subjective reports and objective neuropsychological test performance. Objective: The memory-clinic denoted two clinical "grey zones": 1) subjective cognitive decline (SCD; n = 107) with normal objective test scores, and 2) isolated low test scores (ILTS; n = 74) without subjective complaints to observe risk for future decline. Methods: Initial and annual follow-up clinical research evaluations and consensus diagnosis were used to evaluate baseline characteristics and clinical progression over 2.7 years, compared to normal controls (NC; n = 117). Results: The ILTS group was on average older than the NC and SCD groups. They had a higher proportion of people identifying as belonging to a minoritized racial group. The SCD group had significantly more years of education than the ILTS group. Both ILTS and SCD groups had increased risk of progression to mild cognitive impairment. Older age, minoritized racial identity, and baseline cognitive classification were risk factors for progression. Conclusion: The two baseline risk groups look different from each other, especially with respect to demographic correlates, but both groups predict faster progression than controls, over and above demographic differences. Varied presentations of early risk are important to recognize and may advance cognitive health equity in aging.