A - 21 The Association between Tau Pathology and Cognitive Impairment in Alzheimer’s Disease in the Democratic Republic of Congo

Abstract Objective Previous studies in Western countries have shown that tau accumulation is more closely connected with cognitive decline in Alzheimer’s disease (ad). This association has not yet been investigated in the Sub-Saharan African countries/Democratic Republic of Congo (DRC). We investigated the association between phosphorylated tau (p-Tau) level and cognitive performance of older adults from the DRC. Method Blood and neuropsychological tests were collected on 80 Congolese older adults with suspected ad. Participants were classified according to the biomarkers of their ATN profiles with positive “A” values based on β-amyloid <0.061 and “T” values based on p-Tau 181 < 4.50, as well as APOEε4 using Simoa assays. An analysis of covariance examined the differences in memory performance for each pathological group, controlling for age, education, gender, and APOEε4 status. Results A-T- (n = 36) consisted of age (M = 71.3, SD = 7.44), gender (48.6% female), education level (M = 9.80, SD = 5.44), and APOEε4 (38.2%). A + T- (n = 29) consisted of age (M = 73.1, SD = 7.75), gender (62.1% female), education level (M = 7.21, SD = 5.92), and APOEε4 (41.4%). A + T+ (n = 15) consisted of age (M = 78.1, SD = 4.62), gender (60.0% female), education level (M = 6.60, SD = 3.46), and APOEε4 (93.3%). Overall, there were significant effects of memory performances on A-T- participants: verbal memory immediate (p = 0.0089), delayed (p = 0.00096), and recognition (p = 0.0104); and visual memory delayed (p = 0.00058) and recognition (p = 0.00039). Conclusion Reduced memory performance and p-Tau levels were associated in Congolese adults with and without ad. This study suggests abnormal tau accumulation underlies cognitive deficits in ad and could be used as an early marker of ad pathology for various populations in Sub-Saharan African countries.