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Diagnosis Neurology & Neurosurgery

Alzheimer's Disease

There is no single diagnostic test that can diagnose Alzheimer's disease. The process involves several tests and may take more than a day. These tests make it possible to diagnosis Alzheimer's with an accuracy of about 90 percent.

There are two abnormal structures in the brain associated with Alzheimer's disease — amyloid plaques and neurofibrillary tangles:

  • Amyloid Plaques Amyloid plaques are sticky clumps or patches of protein surrounded by the debris of dying nerve cells in the brain.
  • Neurofibrillary Tangles These are the damaged remains of protein called tau, which are required for normal brain function. In Alzheimer's, threads of tau protein become twisted, which researchers believe may damage neurons and cause them to die.

Research has provided clues about why the neuron cells die, but scientists have not identified the role plaques and tangles play in the disease and if they're the key factors.


At the UCSF Memory and Aging Center, an assessment will involve neurologists, radiologists, pharmacists, nurses and other health professionals. The evaluation may include a series of tests to measure memory, reasoning, vision-motor coordination and language skills. In addition, the evaluation may include:

  • Brain Scans These tests will be performed to detect other possible causes of dementia such as stroke.
  • Interviews An interview with the patient and another person close to the patient, such as a relative, spouse or close friend who can provide examples of memory loss and functional decline.
  • Laboratory Tests Lab tests, such as blood and urine tests, may provide information about problems other than Alzheimer's that could cause dementia.
  • Medical History Information about mental or physical conditions, prescription and nonprescription drug use, and family medical history will be gathered.
  • Mental Status An evaluation will be conducted to assess sense of time and place; ability to remember, understand and communicate; and ability to do simple math problems.
  • Physical Exam The patient's nutritional status, blood pressure and pulse will be assessed. Tests of sensation, balance and other functions of the nervous system also will be conducted.
  • Psychiatric Evaluation An assessment of mood and other emotional factors that could cause dementia-like symptoms or may accompany Alzheimer's disease will be performed.

UCSF Health medical specialists have reviewed this information. It is for educational purposes only and is not intended to replace the advice of your doctor or other health care provider. We encourage you to discuss any questions or concerns you may have with your provider.