It's important to seek a doctor's diagnosis as soon as possible. There are treatable conditions that can mimic Alzheimer's symptoms, and other possible reasons for symptoms must be investigated thoroughly to determine the true cause.
In addition, treatments currently available for Alzheimer's – while limited in their effectiveness and in the number of people they help – have the best chance of working when begun early in the disease. Prompt diagnosis also enables people and families to take immediate action to prepare for worsening symptoms and make appropriate plans for the future.
Alzheimer's Diagnosis Truths
There is currently no single test that accurately diagnoses Alzheimer's disease, so doctors use a variety of assessments and laboratory measurements to make a diagnosis. (For more on this, please see "What types of tests will the doctor do?") Doctors focus on ruling out all other possible causes of symptoms, which might include reactions to medications, other illnesses or psychological issues such as grief. A diagnosis is said to be either possible (not all other causes can be ruled out) or probable (all other causes have been ruled out). A definitive diagnosis of Alzheimer's is possible only by examining brain tissue after death.
In specialized research and diagnostic facilities, such as the Alzheimer's disease centers supported by the National Institute on Aging, Alzheimer's can be diagnosed with 80 percent to 90 percent accuracy.
Click here to learn more about scientific research aimed at improving the diagnosis of Alzheimer's.
Alzheimer's Diagnosis Tests
Diagnosing Alzheimer's will likely involve several types of evaluations and may take more than one day. Evaluations commonly performed include:
Medical history: an interview or questionnaire to identify past medical problems, difficulties in daily activities and prescription drug use, among other things. The doctor may wish to speak to a close family member to supplement information.
Physical examination: which should include evaluations of hearing and sight, as well as blood pressure and pulse readings.
Standard laboratory tests: might include blood and urine tests designed to help eliminate other possible conditions. These will measure things like blood count, thyroid and liver function, and levels of glucose and other blood-based indicators of illness. A depression screening should also be conducted. In some cases, a small sample of spinal fluid may be collected for testing.
Neuropsychological testing: Doctors use a variety of tools to assess memory, problem-solving, attention, vision-motor coordination and abstract thinking, such as performing simple calculations in your head. The goal is to better characterize the types of cognitive symptoms present, which might provide clues to the underlying cause.
Brain-imaging scan: A "structural" brain scan such as CT or MRI is recommended to rule out brain tumors or blood clots in the brain as the reason for symptoms. Many scientists are trying to determine if other brain-imaging techniques might be able to identify telltale signs of early Alzheimer's reliably enough to be used as diagnostic tools.
Alzheimer's Diagnosis Specialists
Most people usually turn first to their primary physician. Going to a doctor you know, or who knows you or your affected loved one, can ease anxiety. In some cases, it may be prudent to request to be referred to a specialist in Alzheimer's diagnosis, which might be a neurologist, a geriatric psychiatrist or another type of doctor.
(courtesy of Fisher Center for Alzheimer's Research)