Alzheimer's disease has a major impact on the health of Canadians. About 560,000 Canadians suffer from some type of dementia (mental deterioration), and more than 60% of these have Alzheimer's disease. The Alzheimer's Society of Canada estimates that the annual cost to Canadians to care for those living with dementia is over $10 billion.
There will be over 1 million Canadians living with dementia by the year 2038, largely because the "baby boom" generation (people born between 1946 and 1960) will have reached old age. The risk of developing Alzheimer's disease doubles every 5 years after the age of 65.
Exactly how and why Alzheimer's disease develops is still not understood. Somehow, cells are damaged and eventually die in different areas of the brain. The damaged areas of the brain contain abnormalities called beta amyloid plaques and neurofibrillary (or tau) tangles. The death of brain cells leads to dementia, characterized by memory loss, impaired judgment, and behavioural changes.
Eventually, the person loses their speech as well as their bladder and bowel control. People with Alzheimer's typically die of infections such as pneumonia or other medical problems. Most people live for about 8 to 10 years after diagnosis, but some have lived for up to 20 years.
Each case of Alzheimer's usually affects at least two lives: the person with the condition, and the patient's spouse or child who gradually becomes a full-time caregiver as the disease progresses. Caring for an individual with Alzheimer's can be demanding and stressful. Many caregivers must eventually face the difficult decision of placing their loved one in institutional care.
With Alzheimer's, we look more at risk factors than direct causes as these are unclear most of the time. The greatest risk factor for Alzheimer's is age, with most cases occurring after the age of 65.
There may be a genetic factor in Alzheimer's disease, since we know that while uncommon, it sometimes runs in families. Familial Alzheimer's disease (FAD) is the name given when Alzheimer's disease is clearly passed on from generation to generation in a family. It typically comes on before the age of 60, and the Alzheimer's gene turns up in many family members. However, FAD only explains a small portion of all Alzheimer's disease cases. The most common form of Alzheimer's disease, sporadic Alzheimer's disease, may also run in families, but to a much lesser degree. It usually affects people after the age of 65.
Even if no one in your family has had Alzheimer's, you can still get Alzheimer's disease.
Other possible risk factors include:
- head injury: studies show that people who have suffered concussions are more likely to develop Alzheimer's later on.
- gender: women are more likely than men to suffer from Alzheimer's (this is due to the increased life expectancy of women, not due to gender).
- education: Research suggests that better educated people are less prone to Alzheimer's. Those who already have the disease do better if they keep mentally active – an unused brain may deteriorate faster.
- smoking: smokers are more likely to develop Alzheimer's disease compared to non-smokers. They are also more likely to develop other types of dementia.
- prions: some scientists speculate that prions, tiny infectious particles made of protein, may be involved in Alzheimer's disease by infecting the brain.
- cardiovascular disease risk factors: many conditions that affect the heart and blood vessels (e.g., high blood pressure, high cholesterol, diabetes, obesity) are associated with an increased risk of developing Alzheimer's disease and other types of dementia.
Symptoms and Complications
Mild forgetfulness is normal with advancing age, but healthy older people are usually good at remembering what's most important to them. There is reason for concern if they start forgetting what they were just doing, get lost in their own neighbourhood, or start displaying uncharacteristic or inappropriate behaviour. If your loved one is always misplacing their keys, it may mean nothing. If they start leaving them in the fridge or the sugar bowl, it may be cause for concern.
One of the most recognizable symptoms of Alzheimer's disease is a speech problem, such as a person choosing the wrong words, or not understanding simple sentences. Problems with numbers are also common. These are the most reliable signs of early-stage Alzheimer's disease. Other early signs include forgetfulness about recent events (loss of short-term memory), trouble with tasks such as housework or balancing a chequebook, and poor judgment.
In the later stages, people with Alzheimer's disease begin to have trouble caring for themselves and recognizing friends or loved ones. They may become confused, agitated, or aggressive.
The Alzheimer's Society of Canada lists these 10 warning signs to be aware of:
- memory loss that affects day-to-day function
- difficulty performing familiar tasks
- problems with language
- disorientation of time and place
- poor or decreased judgment
- problems with abstract thinking
- misplacing things
- changes in mood and behaviour
- changes in personality
- loss of initiative
Making the Diagnosis
Unfortunately, there's still no safe, definitive test for Alzheimer's disease. The diagnosis is made based on the type and progression of symptoms and by eliminating the many other possible causes of dementia, which include:
- vascular dementia – caused by small strokes that damage brain tissue
- nutritional and vitamin deficiencies, such as pernicious anemia or pellagra
- liver, kidney, heart, lung, or thyroid disease, which can all cause temporary or permanent mental impairment
- dementia pugilistica – "boxer's brain," caused by repeated head trauma
- Parkinson's disease, Huntington's disease, or end-stage multiple sclerosis – the dementia of Parkinson's disease in particular can be hard to distinguish from Alzheimer's disease, as they share many symptoms
- depression – this treatable condition is sometimes mistaken for Alzheimer's disease
- medications – several medications can cause symptoms (e.g., agitation, confusion, or disorientation) that look like Alzheimer's disease, including some pain medications and certain medications used for depression or anxiety – talk to your doctor or pharmacist to find out whether a medication you or a loved one is taking could cause these symptoms
These and other possible causes of dementia can often be identified with a few tests and questions. If the symptoms of Alzheimer's are present, and there's no other explanation for them, the physician will give a diagnosis of "probable Alzheimer's disease." This diagnosis is right 9 times out of 10. Biomarkers are being identified to help devise a test for Alzheimer's disease, which might be available in the future.
Treatment and Prevention
Because there is currently no cure for Alzheimer's disease, treatment focuses on relieving symptoms and maintaining the quality of the person's life. Certain medications, called cholinesterase inhibitors, can help maintain brain function and delay the progression of the disease, but cannot reverse the changes. People with moderate-to-advanced disease may be treated with a medication called memantine, which can provide some benefit. This medication can also be used by people who do not tolerate cholinesterase inhibitors. However, the course of the disease is such that it eventually continues to worsen.
Fortunately, there are a number of ways to help people with Alzheimer's disease that do not involve medications. These include:
- reminder notes
- personal organizing tools such as date books and beepers
- providing instructions for activities such as bathing, eating, and dressing
- family counselling and support
- behaviour training for inappropriate behaviours
The behaviour changes of Alzheimer's disease can be very distressing to people and their families or caregivers. Medications may be used to control severe agitation or behaviours which may result in physical harm or are very distressing to the person. However, in many cases agitation can be controlled without medications.
Not enough is known about the causes of Alzheimer's to provide clear advice about how to prevent it. However, addressing suspected modifiable risk factors (risk factors that can be changed), such as smoking, high blood pressure, and obesity may potentially help.
An increased level of fitness helps the brain to stay healthy, so aerobic exercise may be a factor in either preventing or delaying the onset of Alzheimer's. Computerized "brain fitness" programs are becoming popular to keep the brain active and possibly protect it from deterioration. So far there is no convincing scientific evidence that this is effective in preventing Alzheimer's, but investigations are ongoing.
Contact your local Alzheimer's society for more information on new advances in research and suggestions for helping a person who has Alzheimer's disease.