Objective: The aim of this study was to investigate the influence of cerebrospinal fluid (CSF), amyloid β42(Aβ42), phosphorylated tau181 (p-tau), and total tau (t-tau) on cognitive functioning.

Methods: We analyzed the ability of the CSF biomarkers Aβ42, p-tau, and t-tau to predict the results on the Cambridge Cognitive Examination–Revised (CAMCOG-R), a cognitive screening test that assesses multiple cognitive domains, in 65 memory clinic patients (73.1±8.2 years) (n=30 probable Alzheimer's disease [AD], n=7 possible AD, n=12 non-AD dementia, n=16 mild cognitive impairment).

Results: We found no correlations between CSF biomarkers and CAMCOG-R performance in the whole group, nor in subgroups based on aberrant biomarker concentrations.

Discussion: Changed concentrations of CSF amyloid β42, p-tau, and t-tau cannot be directly linked to cognitive function in our sample of patients with cognitive impairment. Possibly, compensatory mechanisms such as cognitive reserve determine cognitive performance, rather than the absolute amount of damage caused by Aβ deposition and tangle formation. In addition, abnormal CSF biomarker concentrations may not be a direct reflection of the amount of neuronal damage, but merely serve as an indicator of AD pathology.

Conclusion: While CSF biomarkers are valuable in establishing AD pathology, they cannot be used to predict severity of cognitive impairment.