Dementia: a brief review.

Dementia is an increasingly common diagnosis in our aging population, and the numbers are expected to rise exponentially in coming years. Alzheimer's disease alone now affects 4.5 million people in the US, while millions more are currently affected by vascular dementia, Lewy Body disease and frontotemporal dementia. Each of these is a distinct entity, though overlapping symptoms and comorbidities occur frequently. Within the past two decades research has progressed rapidly on multiple fronts, including epidemiology, etiology, pathology, diagnosis and treatment. It is important for clinicians to recognize early signs and symptoms of dementia, and to note critical differences among them. Dementia research has moved beyond description of symptoms and clinicopathological correlation to the elucidation of risk factors, the pathobiology of the disease process, and most important, to the first generation of dementia treatments. Our purpose here is to review the current state of knowledge and directions of research for the four major dementias noted above. We are entering an era of dementia care that will be based upon the identification of potentially modifiable risk factors and early disease markers, and the application of new disease-specific diagnostic tools and treatment modalities.