Dr. Seth Gale points out evidence of Alzheimer’s disease on an MRI at the Center for Alzheimer Research and Treatment at Brigham And Women’s Hospital, in Boston, Mass., on March 30, 2023.BRIAN SNYDER/Reuters
The Alzheimer Society of Canada predicts there will be more than 1.7 million people in Canada living with dementia in 2050, nearly three times the estimated 650,000 today.
Treatments are limited and there is no cure, but for the first time in decades, there hope: the first-ever disease-modifying drugs are being tested in major clinical prevention trials. (Prevention trials are used to evaluate the effectiveness of drugs designed to prevent a disease.)
To better understand the disease and its signs and symptoms, we’ve rounded up the most frequently asked questions about Alzheimer’s and done our best to answer them.
What is Alzheimer’s?
Alzheimer’s disease is a chronic neurodegenerative disease that destroys brain cells, causing a person’s memory and cognition to deteriorate over time. The Canadian Alzheimer Society says that the disease is not a normal part of aging, and is irreversible.
What’s the difference between Alzheimer’s and dementia?
Alzheimer’s is the most common form of dementia, which is an umbrella term for more than 50 brain diseases and conditions that affect memory and thinking. The terms are not interchangeable.
Is Alzheimer’s disease genetic or hereditary?
The Canadian Alzheimer Society explains that most cases of Alzheimer’s disease are sporadic, meaning they do not run in families.
Researchers have found more than 70 genes that may increase the risk of developing Alzheimer’s disease. Most of them are considered susceptibility genes, meaning they do not directly cause Alzheimer’s, but make a person more susceptible to developing it.
The presence of the APOE e4 gene indicates susceptibility for developing sporadic Alzheimer’s disease.
Though fewer than five per cent of Alzheimer’s cases are caused by deterministic genes that run in families – referred to as familial or inherited Alzheimer’s – people who have a parent with Alzheimer’s are at an elevated risk of developing the disease.
Three familial Alzheimer’s disease genes have been discovered so far: two presenilin genes (PSEN1 and PSEN2), and an amyloid precursor protein (APP) gene. People with these genes are very likely to develop young onset familial Alzheimer’s disease before the age of 65.
How is Alzheimer’s diagnosed in Canada?
Canadian doctors currently diagnose Alzheimer’s using visual and verbal cognitive tests, accompanied by a CAT or MRI scan and blood tests to rule out other causes of dementia, such as stroke or severe B12 deficiency.
It used to be that Alzheimer’s disease could only be confirmed at autopsy, when pathologists looked for amyloid plaques and neurofibrillary tangles.
Today, amyloid plaques and tau tangles can be confirmed using a PET scan or by testing cerebrospinal fluid obtained through a lumbar puncture. Canadian doctors, however, don’t routinely use PET scans or spinal taps for diagnosis because there’s little point in confirming the presence of amyloid when there aren’t any authorized anti-amyloid medications yet available here.
Blood tests also exist to detect the disease, but aren’t yet available in Canada outside of research studies.
What are the signs of dementia and Alzheimer’s?
The Alzheimer Society of Canada shares 10 warnings signs for dementia:
- Memory changes that affect day-to-day abilities
- Difficulty doing familiar tasks
- Changes in language and communication
- Disorientation in time and place
- Impaired judgment
- Problems with abstract thinking
- Misplacing things
- Changes in mood, personality and behaviour
- Loss of initiative
- Challenges understanding visual and spatial information
What are the stages of Alzheimer’s?
The Canadian Alzheimer Society explains the four stages as:
- Early stage: Symptoms are mild. A person at this stage is fully aware of their condition and only needs minimal assistance, if requested.
- Middle stage: Symptoms start becoming more noticeable. More assistance will be needed to help the person living with Alzheimer’s accomplish daily tasks.
- Late stage: Once the person reaches this stage, they will eventually become unable to communicate verbally or look after themselves. Quality of care is important to ensure that the person has quality of life.
- End-of-life: Cognitive decline has progressed to the point where the person needs 24-hour care. The focus shifts to palliative care and comfort to ensure quality of death.
What are the symptoms of Alzheimer’s?
The symptoms of Alzheimer’s disease vary depending which stage a person is in.
People with mild dementia due to Alzheimer’s disease may experience:
- Memory loss of recent events.
- Trouble with problem-solving, complex tasks and sound judgments
- Changes in personality.
- Trouble organizing and expressing thoughts.
- Getting lost or misplacing belongings.
People with moderate dementia due to Alzheimer’s disease may:
- Show increasingly poor judgment and deepening confusion
- Experience even greater memory loss.
- Need help with some daily activities.
- Undergo significant changes in personality and behaviour.
People with severe dementia due to Alzheimer’s disease may:
- Lose the ability to communicate
- Require daily assistance with personal care.
- Experience a decline in physical abilities.
What causes Alzheimer’s?
The cause of Alzheimer’s disease is currently unknown, but age is the most significant factor contributing to the risk of getting the disease.
There is an ongoing scientific debate about beta amyloid plaque buildup, a biological feature that separates Alzheimer’s disease from other causes of dementia, and whether or not it causes or contributes to the disease.
Is there a cure for Alzheimer’s?
No. There is currently no cure for dementia or Alzheimer’s disease.
What is the treatment for Alzheimer’s?
There are some treatments available in Canada to help manage the issues people experience from the disease.
Four medications approved in Canada may help people with symptoms such as changes in language, thinking abilities and movement. They are:
- Aricept, or its generic version, Donepezil
- Reminyl ER, or its generic version, Galantamine
- Exelon, or its generic version, Rivastigmine
- Ebixa, or its generic version, Memantine
Donepezil works by slowing the breakdown of acetylcholine, which sends messages between nerve cells and the brain. Rivastigmine and Galantamine also work by affecting the brain’s acetylcholine levels. Memantine works by blocking the effects of a chemical called glutamate, which also sends messages between nerve cells in the brain.
Health Canada is looking at two anti-amyloid drugs, both part of major clinical trials for the prevention of Alzheimer’s dementia.
Lecanemab, sold under the brand name Leqembi, has been approved in the United States, Japan and China for patients with mild cognitive impairment or mild dementia due to Alzheimer’s disease. It’s being tested as a prevention drug in the clinical trial, AHEAD.
Donanemab, which showed promise in early symptomatic Alzheimer’s disease in a phase 3 study, but has yet to be approved in the U.S. or Canada, is being tested as prevention in the clinical trial TRAILBLAZER-ALZ-3.
With files from Kelly Grant.