Abnormal levels of beta amyloid (Aβ42) and tau protein concentrations in the cerebral spinal fluid (CSF) have been largely described in Alzheimer's disease (AD). Thus, CSF analysis of these biomarkers has been incorporated in recent AD diagnostic criteria, and it is increasingly performed for neurodegenerative dementia diagnostic workout in clinical setting. Nevertheless, the precise biomarkers CSF features in neurodegenerative dementia, either AD or Frontotemporal dementia (FTD), are still not fully clear today. This is mainly due to lack of CSF clear cutoff values due to a well-known intersite (but even intrasite) variability of CSF procedures, ranging from collection to analysis. Applying CSF biomarker ratios, rather than their single values could represent a useful tool, especially for the differential diagnosis of different forms of dementia. We explored clinical values of six CSF ratios (by combining Aβ42 and tau) in order to better discriminate between AD and FTD; we identified Aβ42/p-Tau181 ratio as a potential good candidate for helping differentiating AD from FTD in the clinical practice.
Keywords: Alzheimer’s disease; Beta amyloid; CSF ratio; Frontotemporal dementia.