Because dementia is a syndrome which arises from many possible medical conditions, doctors must work methodically to identify the root cause of a patient’s cognitive and behavioral limitations.
	Even though the structural features of Alzheimer’s disease have been recognized for many decades,  there remains no definitive way to confirm the presence of these changes in living patients.   Since brain samples (biopsies) are not generally obtained for this purpose -- due to the fact that brain surgery is invasive, expensive, and potentially hazardous – physicians render the diagnosis of Alzheimer’s by evaluating the quality and progression of symptoms, and by ruling out other potential causes of disablity.
	Many researchers are now working to identify “biomarkers” which will permit the accurate determination of Alzheimer’s disease, based upon non-invasive tests of biological samples (blood, urine, cerebrospinal fluid) or via brain scan techniques.  For now, however, the gold standard for determining Alzheimer’s disease remains the postmortem examination of brain tissue – otherwise known as autopsy.