Alzheimer disease cerebrospinal fluid biomarkers predict cognitive decline in healthy elderly over 2 years

: The aim of this study is to check the ability of cerebrospinal fluid biomarkers of Alzheimer disease (CSF-BMK-AD) to make a discrimination checklist within a healthy group, according to their cognitive development at 2 years of obtaining the sample.

Between 2008 and 2010, 67 subjects without cognitive or behavioral disorders were included as a control group in a study on CSF-AD-BMK. Neuropsychological assessment at baseline and at follow-up had been carried out 2 years later. CSF was obtained at the inclusion. It was analyzed by Innotest reagents to measure amyloid-β (Aβ1-42), total-τ (T-τ), and phosphorylated τ181 (P-τ181p) protein levels, as well as T-τ/Aβ1-42 and P-τ181p/Aβ1-42 ratios.

Two years after inclusion, 28 subjects were not able to be checked for cognitive evolution. Of those who were seen for follow-up (n=39), 29 were cognitively stable and 10 showed cognitive impairment. We found significant differences in Aβ1-42 protein level (820 vs. 1359 pg/mL, P<0.003), in the T-τ/Aβ1-42 ratio (0.40 vs. 0.19, P<0.009), and in the P-τ181p/Aβ1-42 ratio (0.09 vs. 0.04, P<0.003) when both groups were compared.

CSF-BMK-AD are able to discriminate between subjects in a group initially asymptomatic depending on their cognitive evolution at the 2 years' follow-up. These results are consistent with the decrease of CSF Aβ1-42 protein levels as the first finding in preclinical AD showed.