Abstract
BACKGROUND: The study of the association of biomarkers and neuropsychological assessment can contribute to the understanding of the biological mechanisms associated with the evolution of the neurodegenerative process, as well as to the definition of risk factors for the conversion of patients with cognitive decline into dementia due to Alzheimer's disease (ADD). Our main objective was to determine the relationship between performance on the Dementia Rating Scale (DRS) and the main biomarkers of Alzheimer's Disease. METHOD: Sixty‐four older adults from the Cog‐Aging Brazil cohort with low educational levels were recruited and split into three groups: Cognitively Unimpaired (CU, n = 18), Mild Cognitive Impairment (MCI, n = 21) and Alzheimer's Disease Dementia (ADD, n = 25). Levels of CSF Aβ42 and p‐Tau 181 were assessed by Luminex xMAP technique. Descriptive statistics were carried out according to normality tests. Spearman correlation tests were explored to analyze associations between CSF levels of Aβ42, p‐Tau181, and p‐Tau181/Aβ42 ratio and performance in DRS. Significant associations between p‐Tau181 and Aβ42 and total DRS score (DRST) were explored in linear regression analysis adjusted for age, sex, education, and APOE ε4 carrier status. This study was approved by UFMG Ethics Committee. RESULT: The median age of the participants was 75 years (IQR 9.25). The education level was 4 years (IQR 4.25), DRST mean 117.73 (14.04). A negative significant correlation was found between CSF p‐Tau181 and the domains of DRS: Memory (rho ‐0.533) (p < .001) and DRST (rho ‐0.482) (p < .001). No significant correlation was found for Aβ42. A significant correlation between DRS and p‐Tau181/Aβ42 ratio was found in Memory (rho ‐0.430) (p < .001) and DRST (rho ‐0.349) (p < .05). The linear regression model was statistically significant (F = 8.81) (p < .001) with R2 of 0.495. The Linear regression analyses showed a significant association with DRS and p‐Tau181(β = ‐0.548; CI 95%: [ ‐0.260, ‐0.105]; (p < .001) and education (β = 0.420; CI 95%: [0.671, 2.159]; (p < .001). CONCLUSION: The higher levels of p‐Tau181 seem to correlate with a worse performance in Memory and total DRS. Considering DRST, p‐tau was still associated with worse performance, even when adjusted by sociodemographic factors.