Dementia update: diagnosis and neuropsychiatric aspects.

Many disorders--including vascular disease, alcoholism, Huntington's disease, drug toxicity, metabolic disorders, brain tumors, depression, and other psychiatric disorders--can cause dementia. Moreover, 50% of all dementia patients have Alzheimer's disease. Guidelines have been established to define the types of dementia. A detailed history, which may note previous depression, and a physical examination are essential. Assessment of the patient's mental status and a neurological examination may help to distinguish other forms of dementia from Alzheimer's disease. Brain imaging and psychometric testing may also help to establish a diagnosis. Metabolic screening for reversible causes of dementia, such as thyroid disturbance or electrolyte-imbalance, is essential. Common features of Alzheimer's disease include memory loss; difficulty with problem solving, abstractions, and calculations; and language and visuospatial deficits. Delusions are common in the early phase of the disease. It is not yet possible to diagnose Alzheimer's disease with complete accuracy. Additional neurophysiological and biochemical markers for diagnosis must be developed.