Seeing with new eyes: finding a path to early intervention trials in Alzheimer's disease.

The clinical course of Alzheimer's Disease (AD) and other degenerative disorders affecting cognition can be visualized as a progression from normal cognition through the syndrome of Mild Cognitive Impairment (MCI) to dementia. The use of biomarker data can supplement clinical characterization and identification of MCI and dementia pathologies. Clinical staging algorithms that use both clinical and biomarker information can assist in the early identification of AD patients. A comprehensive outcome measure such as the Clinical Dementia Rating Sum of Boxes (CDR-SB), which has components that assess both cognitive and functional domains in parallel deserves consideration as a primary outcome measure for early AD clinical trials.