Diagnosis of Alzheimer's disease (AD), the most common form of dementia, involves neuropsychological testing, limited laboratory tests and brain imaging. Current therapeutic options for AD are symptomatic treatments that target dysfunctional neurotransmitters associated with the disorder. Recent research has focused on therapeutic strategies that inhibit the production and aggregation of amyloid beta protein (Aβ) in plaques and increase its clearance from the brain. Such strategies are likely to be most effective at pre-clinical stages of the disease, before widespread synaptic and neuronal loss occurs. Thus, there is a need for biomarkers that predict disease course and outcome and monitor disease progression and treatment efficacy. The development of such biomarkers for AD is critical to translating the efficacy of new therapies.