The present study was undertaken to validate the measurement of biomarkers as a supplement to the latest diagnostic criteria for Alzheimer disease (AD) dementia by National Institute on Aging-Alzheimer's Association (NIA-AA) work group using a sample attending a tertiary care center in Southern India. A total of 20 subjects diagnosed clinically as Alzheimer's dementia according to the NIA-AA criteria for AD were included in the study. The CSF biomarkers Aβ42, t-tau, and p-tau181 were assessed. The biomarker results were compared among mild and moderate to severe AD as defined in the NIA-AA work group guidelines. The results revealed that the amount of Aβ42 was very low in all the 20 samples (<50pg/ml) collected from mild AD cases with CDR score of 1 (n=8), and moderate to severe AD cases with CDR >1 (n=12). t-tau and p-tau levels were in the range of 39.45±5.09pg/ml and 13.06±7.32pg/ml for CDR 1 group. t-tau and p-tau levels were in the range of 49.9±11.28pg/ml and 33.94±15.13pg/ml for moderate to severe cases. Analysis of the data revealed statistically significant differences in the p-tau/t-tau ratio and p-tau/Aβ ratio between CDR 1and CDR >1 AD cases (p<0.001) suggesting that p-tau/t-tau and p-tau/Aβ ratio are good indicators of severity of dementia with discriminative value in differentiating mild AD from moderate to severe AD.
Keywords: Alzheimer disease; Amyloid β; Biomarker; Cerebrospinal fluid; Tau.
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