CSF biomarkers for Alzheimer's disease: current utility and potential future use.

Over the past 15 years, cerebrospinal fluid (CSF) biomarkers have been shown to be useful for both the diagnosis as well as the prognosis in Alzheimer's disease. It has been shown the CSF levels of amyloid-β (Aβ)(42) are a very good marker for the presence of amyloid deposition in the brain regardless of clinical status and that total tau and phosphorylated forms of tau are useful in detection of neurodegeneration. When combined together, these CSF markers are useful not only in differential diagnosis but also in predicting conversion and rate of progression from mild cognitive impairment/very mild dementia to more severe impairment. The markers are also useful in predicting conversion from cognitive normalcy to very mild dementia. This field is briefly reviewed and recommendations for future studies in this area are provided.