Alzheimer's disease: Making a diagnosis

What tests are used to diagnose Alzheimer's disease?

In spite of the fact that it is so common, Alzheimer's disease often goes unrecognised or is misdiagnosed in its early stages. Many doctors and nurses, patients and family members mistakenly view the early symptoms of Alzheimer's disease as the inevitable consequences of ageing.

Some disorders that can result in dementia (such as depression, poor nutrition, and medicinal interactions) are curable, but Alzheimer's disease is not. Therefore, it is very important to diagnose the cause of the dementia early and correctly. In addition, some Alzheimer's disease symptoms (such as incontinence and depression) can be effectively treated, so it's better to identify these as soon as possible.

An early and accurate diagnosis of the cause of dementia is important for the following reasons:

• To rule out Alzheimer's disease and ease the patient's and family's concern.
• To identify any treatable condition and initiate treatment as appropriate.
• To identify Alzheimer's disease at the earliest possible stage; this gives the patient and family time to plan for the future needs and care of the patient. This also allows the patient to start using some medicines that are useful in the earlier stages of Alzheimer's.

Alzheimer's disease cannot be definitively diagnosed until after death, when the brain can be closely examined for certain microscopic changes caused by the disease.

However, through thorough testing and a "process of elimination", doctors today can diagnose what they refer to as probable Alzheimer's disease with almost 90% accuracy.

The following things may be used to help diagnose Alzheimer's disease.

Patient history

A history from the patient helps the doctor assess a person's past and current health situation. It also helps the doctor evaluate whether there are any medical problems, develop a plan of treatment, and monitor the patient's health over time.

During this evaluation, the doctor asks the patient a series of questions.

A thorough patient history includes:

• Patient's identifying information.
• Information about the main problem, including any difficulties in daily living.
• Information about other symptoms.
• History of any current illness.
• Past medical history.
• Medications being taken.
• Current health status.
• Psychosocial history - such as marital status, living conditions, employment, sexual history, important life events.
• Mental state - this is a series of questions that the doctor will ask to determine if the person is experiencing any evidence of mental health illness, like depression.
• Family history (including any illnesses that seem to run in the family).

Mini-mental state examination

This is a very brief test that the doctor can use to test a person's problem solving skills, attention span, counting skills, and memory. It will give the doctor insight into whether there has been damage to different areas of the brain.

Physical examination

A physical examination enables the doctor to assess the overall physical condition of the patient. If the patient has a medical complaint, the physical examination provides the doctor with more information about that particular problem, which helps him or her determine an appropriate plan of treatment.