A Monocenter, Cross-sectional Study to Compare Different Type of Cognitive Impairment in Multiple Sclerosis Patients and Cerebrospinal Fluid Biomarkers (Beta Amyloid, Total Tau Protein and Tau-phosphorylated Protein).

In multiple sclerosis (MS) sub cortical cognitive impairments are frequently reported. Nevertheless, cortical cognitive troubles, with hippocampic memory troubles have been described. Besides inflammatory damage, early cortical and degenerative damage are well known. In neurodegenerative diseases, three biomarkers of the cerebro spinal fluid (CSF), reflecting lesional mechanisms, are measured: the beta amyloid peptide, the tau total protein, and the phospho tau protein. Preliminary studies shown increased level of tau in MS. No study compare cognitive impairment and biomarkers of CSF.The aim of this study is to measure in the CSF of MS patients these three biomarkers (beta amyloid peptide, tau total and phosphotau) in order to establish correlations between a profile of biomarkers and a pattern of cognitive troubles, cortical or subcortical.The possibility to show, in MS patients with memory hippocampic troubles, a profile of biomarkers closed from the one encountered in AD, could argue in support of the degenerative hypothesis in MS and lead to discuss the interest of the use of AD treatment in MS.