Alzheimer's disease can be reliably diagnosed with a complete examination that includes:

• A complete medical and psychiatric history
• A neurological exam
• Lab tests to rule out anemia, vitamin deficiencies and other conditions
• A mental status exam to evaluate the person's thinking and memory
• Talking with family members or caregivers

You can help your physician by being prepared for the appointment. Bring a list of current medications, a log of symptoms or behavior changes and a list of your questions or concerns. It is also helpful to provide an accurate history of the person's medical conditions and any previous treatment.

There is no simple test to diagnose Alzheimer's disease; a definite diagnosis can only be made by examining brain tissue, usually at autopsy. The patient's brain will be permeated with deposits of amyloid. Sick brain cells are filled with tangles of fibrillary material. While these changes occur in normal aging, a much greater density is found in Alzheimer's patients, which may cause brain cells to stop communicating with each other.

When Alzheimer's disease is suspected, it is important to have a thorough medical and neurological evaluation to identify treatable disorders with Alzheimer's-like symptoms. Illnesses like depression, hypothyroidism, vitamin B12 deficiency, hydrocephalus, cerebral vasculitis, neurosyphilis, AIDS, and stroke can cause dementia, as can alcohol and some medications.

The comprehensive evaluation necessary to rule out these causes and to make a probable diagnosis of Alzheimer's disease includes a complete health history, physical examination, neurological and mental status assessment and other tests including analysis of blood and urine, electrocardiogram and chest x-rays. Documenting symptoms and behavior over time, in a diary fashion, will help the physician understand the person's illness. The physician may order additional tests as needed including computerized tomography (CAT) scan, electroencephalography or a magnetic resonance image (MRI) scan.