Non-linear relationships of cerebrospinal fluid biomarker levels with cognitive function: an observational study
1 OPTIMA, University of Oxford, John Radcliffe Hospital, Headington, Oxford, OX3 9DU, UK
2 Clinical Neuroscience and Ophthalmology, Merck Research Laboratories, 351 N. Sumneytown Pike, North Wales, PA 19454, USA
3 Clinical Development Laboratory, Merck Research Laboratories, 126 East Lincoln Avenue, Rahway, NJ 07065, USA
Alzheimer's Research & Therapy 2011, 3:5 doi:10.1186/alzrt64Published: 17 February 2011
Levels of cerebrospinal fluid (CSF) β-amyloid (Aβ) and Tau proteins change in Alzheimer's disease (AD). We tested if the relationships of these biomarkers with cognitive impairment are linear or non-linear.
We assessed cognitive function and assayed CSF Aβ and Tau biomarkers in 95 non-demented volunteers and 97 AD patients. We then tested non-linearities in their inter-relations.
CSF biomarkers related to cognitive function in the non-demented range of cognition, but these relations were weak or absent in the patient range; Aβ1-40's relationship was biphasic.
Major biomarker changes precede clinical AD and index cognitive impairment in AD poorly, if at all.