Diagnosis and treatment of Alzheimer's disease.

Alzheimer's disease (AD) is a chronic neurodegenerative disorder and the most common cause of dementia. It is one of the principal causes of disability and decreased quality of life among older adults. Progress in our clinical knowledge of AD has led to more reliable diagnostic criteria and accuracy, and research efforts are expanding to uncover the earliest manifestations and even the presymptomatic phases of the disease. The diagnosis of AD is primarily one of inclusion and usually can be made using standardized clinical criteria. There is currently no cure for AD. Current treatment focuses on establishing an early accurate clinical diagnosis, early institution of cholinesterase inhibitors and/or N-methyl-D-aspartate (NMDA) receptor-targeted therapy. Treating medical comorbidities and dementia-related complications, ensuring that appropriate services are provided, addressing the long-term well-being of caregivers, and treating behavioral and psychological symptoms with appropriate nonpharmacologic and pharmacologic interventions also are important. The initiating and propagating pathologic processes and the anatomic location of the earliest changes will become new targets of research and therapeutic development. A possible precursor of AD, mild cognitive impairment (MCI), is under investigation as a possible therapeutic starting point for disease-modifying interventions. This article provides a research update of current understanding in the diagnosis and treatment of AD and in emerging areas of interest such as MCI, detection of AD in the predementia phase, and neuroimaging in AD.