Skip to main content
The Globe and Mail
Support Quality Journalism.
The Globe and Mail
First Access to Latest
Investment News
Collection of curated
e-books and guides
Inform your decisions via
Globe Investor Tools
Just$1.99
per week
for first 24 weeks

Enjoy unlimited digital access
Enjoy Unlimited Digital Access
Get full access to globeandmail.com
Just $1.99 per week for the first 24 weeks
Just $1.99 per week for the first 24 weeks
var select={root:".js-sub-pencil",control:".js-sub-pencil-control",open:"o-sub-pencil--open",closed:"o-sub-pencil--closed"},dom={},allowExpand=!0;function pencilInit(o){var e=arguments.length>1&&void 0!==arguments[1]&&arguments[1];select.root=o,dom.root=document.querySelector(select.root),dom.root&&(dom.control=document.querySelector(select.control),dom.control.addEventListener("click",onToggleClicked),setPanelState(e),window.addEventListener("scroll",onWindowScroll),dom.root.removeAttribute("hidden"))}function isPanelOpen(){return dom.root.classList.contains(select.open)}function setPanelState(o){dom.root.classList[o?"add":"remove"](select.open),dom.root.classList[o?"remove":"add"](select.closed),dom.control.setAttribute("aria-expanded",o)}function onToggleClicked(){var l=!isPanelOpen();setPanelState(l)}function onWindowScroll(){window.requestAnimationFrame(function() {var l=isPanelOpen(),n=0===(document.body.scrollTop||document.documentElement.scrollTop);n||l||!allowExpand?n&&l&&(allowExpand=!0,setPanelState(!1)):(allowExpand=!1,setPanelState(!0))});}pencilInit(".js-sub-pencil",!1); // via darwin-bg var slideIndex = 0; carousel(); function carousel() { var i; var x = document.getElementsByClassName("subs_valueprop"); for (i = 0; i < x.length; i++) { x[i].style.display = "none"; } slideIndex++; if (slideIndex> x.length) { slideIndex = 1; } x[slideIndex - 1].style.display = "block"; setTimeout(carousel, 2500); } //

New diagnostic tests will soon be available to anyone who wants to know if their brains have tell-tale signs of Alzheimer's disease.

The tests include brain scans and spinal-fluid analysis that can detect signs of the distinctive plaques and tangles that are characteristic of Alzheimer's, the most common cause of dementia. There is evidence this damage starts long before people experience memory loss.

Currently, dementia from Alzheimer's disease is diagnosed by memory loss and the inability to carry out daily activities like getting dressed or looking after personal hygiene, coupled with an autopsy report of plaques and tangles.

Story continues below advertisement



PET scan

Perhaps the most important new tool uses positron emission tomography, or a PET scan, to detect amyloid plaques, the clumps of aberrant protein that riddle the brains of people in the advanced stages of the disease.

The amyloid PET scan hasn't been approved in Canada or the United States; The first convincing data on it was presented at an international meeting on Alzheimer's in Hawaii this summer.

It is clearly a step forward because in the past an autopsy was required, says Judes Poirier, a researcher at McGill University and the Douglas Institute in Verdun.

"Now we don't need to wait for people to die to say this is definitely Alzheimer's."



Spinal tap

Scientists are also seeing whether they can detect signs of trouble in spinal fluid. They look for abnormal levels of amyloid and a second protein called tau that forms distinctive tangles in the brains of people with Alzheimer's.



Scans and blood

Magnetic resonance imaging, or MRIs, can detect shrinkage of the hippocampus, a part of the brain involved in memory, and researchers in Texas are working on a blood test that would reliably indicate Alzheimer's.



Genes

Testing for a genetic risk factor associated with Alzheimer's has been available for years, says Dr. Poirier, a pioneer in probing the genetics of the disease. But like, many genetic tests, it isn't definitive. If someone carries two copies of a gene called apoE4, one from each parent, they are nine times more likely to get Alzheimer's, he says. One copy makes them three times more likely.

Story continues below advertisement

In many trials now under way, genetic testing is being done along with the newer diagnostic tools being evaluated, he says.



Coming soon

New guidelines, proposed at the meeting in Hawaii are expected to be adopted in the U.S. as early as this fall, and will influence policy in Canada, says Sandra Black, a researcher at the U of T and Sunnybrook hospital.

Provinces must decide to pay for the tests, she says, although people could probably have them done in the United States.



Is earlier better?

Researchers consider the new diagnostic tests essential tools in the quest to find drugs that will slow or stop Alzheimer's disease.

But they also could cause a dilemma: Would you want to know you're developing an illness that will rob you of your memory and autonomy - and there is little doctors can do?

Yet, if researchers are going to find new treatments, they need to be able to diagnose people earlier, says Robin Hsuing, a University of British Columbia scientist looking for biomarkers for frontal temporal dementia, a form of dementia that tends to hit people younger.

Story continues below advertisement

"We are in a very interesting transition, which I hope is going to be toward some therapies that actually work," says Sandra Black, a Canadian researcher taking part in a large U.S. trial to assess diagnostic tests.

The push for early diagnosis came from the Food and Drug Administration in the United States, says McGill University researcher Judes Poirier, because most major drug companies have something they want to test.

Mild cognitive impairment is an early stage of mental decline but only half of those who are diagnosed go on to develop Alzheimer's. Yet, the preliminary results of a large U.S. study found that 80 to 90 per cent of MCI patients who also had telltale amyloid plaques in their brains and a build-up of tau in their spinal fluid went on to develop dementia, Dr. Hsiung says.

So the initial trials of a drug will likely involve MCI patients. But anything that works for them would likely be tested in people without symptoms, if their tests show signs of brain damage associated with Alzheimer's.

It is also possible that early diagnosis may help patients make lifestyle changes that delay the onset of the disease. Studies suggest that exercise and a healthy diet may be protective. Both measures are widely advocated by doctors to prevent heart disease and stroke, Dr. Black says, but many patients ignore the advice.

They may feel different if they knew they were at high risk for Alzheimer's - or they could become anxious and have trouble getting insurance.

Story continues below advertisement

"You would hate," she says, "for someone to jump off a cliff."

Your Globe

Build your personal news feed

  1. Follow topics and authors relevant to your reading interests.
  2. Check your Following feed daily, and never miss an article. Access your Following feed from your account menu at the top right corner of every page.

Follow topics related to this article:

View more suggestions in Following Read more about following topics and authors
Report an error Editorial code of conduct
Due to technical reasons, we have temporarily removed commenting from our articles. We hope to have this fixed soon. Thank you for your patience. If you are looking to give feedback on our new site, please send it along to feedback@globeandmail.com. If you want to write a letter to the editor, please forward to letters@globeandmail.com.

Welcome to The Globe and Mail’s comment community. This is a space where subscribers can engage with each other and Globe staff. Non-subscribers can read and sort comments but will not be able to engage with them in any way. Click here to subscribe.

If you would like to write a letter to the editor, please forward it to letters@globeandmail.com. Readers can also interact with The Globe on Facebook and Twitter .

Welcome to The Globe and Mail’s comment community. This is a space where subscribers can engage with each other and Globe staff. Non-subscribers can read and sort comments but will not be able to engage with them in any way. Click here to subscribe.

If you would like to write a letter to the editor, please forward it to letters@globeandmail.com. Readers can also interact with The Globe on Facebook and Twitter .

Welcome to The Globe and Mail’s comment community. This is a space where subscribers can engage with each other and Globe staff.

We aim to create a safe and valuable space for discussion and debate. That means:

  • Treat others as you wish to be treated
  • Criticize ideas, not people
  • Stay on topic
  • Avoid the use of toxic and offensive language
  • Flag bad behaviour

If you do not see your comment posted immediately, it is being reviewed by the moderation team and may appear shortly, generally within an hour.

We aim to have all comments reviewed in a timely manner.

Comments that violate our community guidelines will not be posted.

UPDATED: Read our community guidelines here

Discussion loading ...

To view this site properly, enable cookies in your browser. Read our privacy policy to learn more.
How to enable cookies