Differential diagnosis and early detection of dementia.

Of the many potential causes of dementia, Alzheimer's disease (AD) is the most common and accounts for approximately two-thirds of cases in older populations. Typical clinical features help differentiate various other conditions. Screening laboratory tests are generally sufficient for routine evaluations; brain imaging assessments also assist in the differential diagnosis by identifying structural and functional abnormalities. Because new treatments for AD are more likely to delay disease onset than to reverse neuronal damage, early detection methods have practical treatment implications. Recent studies combine genetic risk with neuroimaging assessments as a method of early disease detection; additional techniques aimed at increasing sensitivity and specificity are under development. Such strategies should eventually assist in the early detection of AD and therapeutic monitoring of brain function during antidementia treatments.