How is dementia diagnosed?

Clinically: Usually a clinical diagnosis, no blood work and no imaging test.

History and testing: Dementia by definition impairs a number of different brain areas. A diagnosis is made by taking a history of what problems you are having, ruling out correctable alterantive causes of the problems and testing specific brain functions. Usually head imaging and laboratory tests are helpful in excluding other illnesses.

H & P & Tests: The first step is obtaining a good history and physical. Next is ruling out reversible causes of mental decline such as toxicity, sepsis, or hormone problems. In some cases imaging is necessary, especially if cognitive function changes rapidly. At the very least, i like to entertain the possibility of depression or hypothyroidism before arriving at a diagnosis of dementia.