Symptoms of Alzheimer's disease include loss of memory, judgment and reasoning; difficulty with day-to-day tasks; and changes in communication abilities, mood and behaviour.

If you notice any of these symptoms, it is important to see your doctor.

Why find out?
Symptoms of Alzheimer's disease can be similar to symptoms of other conditions such as depression, thyroid or heart disease, infections, drug interactions or alcohol abuse.

Finding out the cause of the symptoms can help people:
understand the source of the symptoms
get the proper care, treatment and support
plan for the future

Making the diagnosis

There is currently no single test that can tell if a person has Alzheimer's disease. The diagnosis is made through a systematic assessment which eliminates other possible causes. Until the time when there is a conclusive test, doctors may continue to use the words "probable Alzheimer's disease. " However, you should be aware that doctors making this diagnosis are accurate 80 to 90 per cent of the time.

Making the diagnosis can take time. The diagnosis can be made in a family doctor's office, a memory clinic or a hospital. The doctor may or may not feel that the person needs to see a number of health-care professionals to help make the diagnosis. These may include a psychologist, psychiatrist, neurologist, geriatrician, nurse, social worker or occupational therapist. They will look for problems with the person's memory, reasoning ability, language and judgment, and how these affect day-to-day function. The process involves:

Medical history
Both the individual and family members or friends will be asked questions regarding the person's symptoms now and in the past. There will be questions about past illnesses and about family medical and psychiatric history.

Mental status exam
This part of the process tests the person's sense of time and place as well as the ability to remember, express herself and do simple calculations. It may involve exercises such as recalling words and objects, drawing and spelling, and questions such as "What year is it?"

Physical exam
To help rule out other causes, a physical exam will be done. The doctor will look for heart, lung, liver, kidney or thyroid problems that may be causing the symptoms. To evaluate whether other nervous system disorders are causing the symptoms, the doctor will test muscle tone and strength, co-ordination, eye movement, speech and sensation.

Laboratory tests
A number of tests will be done. Detailed blood work will be ordered to help detect problems such as anemia, diabetes, thyroid problems or infections that might be contributing to the symptoms.

Other tests such as X-rays and EEG's (electroencephalogram) may be used to determine the source of the problem. In some centres, scans may be used. The following may be recommended, but are not always necessary for a diagnosis:

CT (computerized tomography) scan and MRI (magnetic resonance imaging) take images of the brain.

SPECT (single proton emission computed tomo-graphy) shows how blood is circulating to the brain.

PET (positive electron tomography) shows how the different areas of the brain respond during certain activities such as reading and talking.

Psychiatric and psychological evaluations
A psychiatric evaluation may be helpful in ruling out other illnesses such as depression which can cause symptoms similar to Alzheimer's disease. Neuro-psychological testing can evaluate memory, reasoning, writing, etc.