Alzheimer disease defined
Alzheimer disease (AD) is a slow, progressive disease of the brain that is most common among the elderly. Various cognitive and behavioural symptoms emerge at different stages of the disease. Since it is progressive, these symptoms usually worsen as the brain continues to deteriorate. To date, there is no known cure for AD, which is one form of dementia.

Dementia (dee-men-sha): Although other diseases or conditions can cause dementia, more than 64% of dementia cases are AD. Dementia appears as:
1. a deterioration or break down of mental abilities;
2. changes in behaviour and personality profound enough to interfere with normal activities.

Biology: what happens to the brain
Several mechanisms are involved in the development of AD. Nerve cells (neurons) in the brain’s memory centres die, fibres within the brain cells become tangled, and a type of protein called beta-amyloid creates “clumps” or “plaques” in the brain. In fact, tangled fibres and beta-amyloid plaques are two types of brain lesions that are always found in the brains of AD patients.

Diagnosis is complicated because many symptoms may be mistaken for natural signs of aging; however, AD is not a routine result of growing older. A positive diagnosis can be made only after a complete evaluation for AD, one that includes physical examination, testing, and observation.

AD is being studied extensively by medical researchers who are focusing on the impact of genetic factors, immune system abnormalities, environmental toxins, a slow-acting virus, and previous brain injury. They are also assessing how certain drugs may affect disease progression. Due to their efforts, current treatment is improving and, with guarded optimism, it is possible that perhaps one day the disease can be arrested or possibly prevented.

Who is at risk/genetic links
AD tends to affect people over age 65, although a very small percentage of those in their 40s will develop this disease. After age 65, the relationship between prevalence and age doubles approximately every 5 years.

In addition to advancing age, possible risk factors include the following:

• A family history of AD or other forms of dementia
• Serious head or brain injuries
• Thyroid disease
• Exposure to toxic levels of aluminum, zinc, and other metals
• Vascular disease

Certain genes have been associated with inherited, early-onset AD. What’s known as Familial (autosomal dominant) AD is, in fact, significantly less common than Sporadic AD, which is believed to be caused by the interaction between environmental and genetic factors.

Recent medical research suggests that people who carry a specific gene variant –apolipoprotein (APoE), ApoE epsilon 4 – may be at increased risk of AD after age 60. Research is being undertaken to further explore this possibility.

Important statistics
• Over 364,000 Canadians, one in 13 over the age of 65, currently have dementia¹
• Approximately 22 million people worldwide are projected to have developed AD by 2025*.

Taken individually, any one of these symptoms will emerge naturally as a person ages. It’s time to see a doctor when more than a few of them occur with enough frequency and severity to interfere with normal daily functioning at home or at work.

1. Memory loss that affects day-to-day function
2. Difficulty performing familiar tasks
3. Problems with language
4. Disorientation of time and place
5. Poor or decreased judgement
6. Problems with abstract thinking
7. Misplacing things
8. Changes in mood or behaviour
9. Changes in personality
10. Loss of initiative

For example, it is not unusual for someone already diagnosed with moderate AD to have periods of lucidity. Nor is it unusual for someone at the earliest stage to appear completely confused. The range of variation among behaviours is something that makes AD particularly difficult and frustrating for caregivers to manage.

Stage 1: Mild AD
• Onset/Duration:
• Gradual/2 to 4 years or longer
• Care level:
• Can independently perform tasks of daily living, but may need light supervision
• Activity level:
• Appears normal to casual observers. Signs of disease may only be obvious to family members or close friends
• Cognitive symptoms:
• Forgetful
• Easily distracted
• Has trouble remembering words
• Loses or misplaces items
• Minor disorientation of time and place
• Impaired judgement and problem solving
• Behavioural symptoms:
• Slight but noticeable personality changes
• Overly emotional
• Moody
• Increasingly passive and apathetic (showing little feeling or emotion)
• May experience depression
• Slow to accomplish daily activities

Stage 2: Moderate AD
• Onset/Duration:
• 4-7 years after first onset/contingent on health and age
• Care level:
• Care requirements increase. Close supervision, home care, adult day care may be very helpful
• Activity level:
• Diminished
• Cognitive symptoms:
• Further memory loss
• Easily lost and disoriented (confused)
• Problems with reasoning and higher-level thinking
• Understanding deteriorates significantly: may have a hard time reading
• Behavioural symptoms:
• May repeat meaningless statements
• Withdrawn: may fail to greet people
• May hide and hoard things
• Anxious and possibly paranoid
• Paces
• Wanders
• Argumentative
• Depressed
• Trouble handling routine daily activities
• Will start using non-specific descriptors more often, such as “thing” or “stuff” (e.g., “that box thing in the living room” for “television”)
• Delusional

Stage 3: Severe AD
• Onset/Duration:
• Gradual/1 to 3 years or longer depending on health and age
• Care level:
• Constant, round-the-clock care required, total dependence on caregivers
• Activity level:
• Cannot manage any task or activity without full assistance
• Cognitive symptoms:
• Long-term memory loss
• Complete loss of language
• Cannot recognize self or family members
• Cannot distinguish between night and day
• Hallucinatory (having strange visions)
• Paranoid (being overly suspicious or fearful)
• Behavioural symptoms:
• Loss of physical co-ordination
• Needs assistance with personal hygiene
• Incontinence
• Ultimately bedridden
• Unable to handle the simplest tasks, such as setting the table
• Extreme: may be violent or completely withdrawn
• Suspicious: may think misplaced items have been stolen

In general, the earlier the disease is diagnosed and treatment begins, the longer the AD patient is able to function.

Reference: 1. Canadian Study of Health and Aging Working Group: Canadian Study of Health and Aging: study methods and prevalence of dementia. Can Med Assoc J 1994;150:899-913.

For information on caring for a loved one with Alzheimer Disease, click here

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