S2‐02‐05: Role of biomarkers in MCI

Both CSF and imaging indicators of disease (biomarkers) that closely reflect the underlying pathology provide an independent measure of pathology based only on biology in contrast to clinical diagnosis done on the basis of clinical examination and neuropsychological tests. The candidate biomarkers corresponding to each of the dominant pathological findings in Alzheimer's disease (AD) are: 1) low CSF Aβ1-42 levels and increased PIB uptake on PIB-PET scans which reflect deposition of Aβ in plaques; 2) high CSF t-tau, p-tau levels and decreased FDG uptake on FDG-PET scans which reflects active axonal and neuronal damage and 3) atrophy seen on MRI scans which is the direct result of loss of neurons, synapses and dendritic arborization. The main aim of this talk is to discuss the utility of these key biomarkers in mild cognitive impairment (MCI). Cross-sectional biomarker measurements serve as measures of disease stage along the cognitively normal to AD continuum and serial biomarker measurements provide information regarding the intensity of the disease i.e. the rate of change in disease related pathology. Measuring biomarkers cross-sectionally and/or longitudinally can aid in answering these four important questions in MCI: 1) early diagnosis of cognitive impairment; 2) prognostic information in MCI including predicting the risk of progression in MCI and differential diagnosis of dementia sub-types; 3) measuring the efficacy of therapeutics and 4) providing mechanistic inferences into the disease process. Both cross-sectional and serial biomarker studies have found that there is an observable change in the candidate biomarkers early in the disease process, these measures correlate well with clinical measures of general cognition and functional status in MCI and are predictive of risk of progression to dementia. In this talk we will discuss the key role played by CSF and imaging biomarkers in the diagnosis, prognosis and disease management of MCI.