Would You Want to Know?
THE IMPACT OF ALZHEIMER’S TESTING ACCURACY.
While there remains no cure for Alzheimer’s disease (AD), medical science has made significant improvements in diagnosing it. Biomarker tests that analyze cerebrospinal fluid, measuring certain proteins associated with AD, have an accuracy rate of upwards of 90%.
That is a major upgrade on previous methods, which involve a series of clinical tests and observations. Depending on the skill and experience of the practitioner, the diagnosis could be correct anywhere from 60% to 80% of the time.
EXPLORING THE IMPACT
Improved accuracy is obviously a good thing. But Dr. Mari DeMarco of the University of British Columbia (UBC) says it raises new questions, both for the person with AD and their healthcare providers.
“Does increased diagnostic accuracy change subsequent medical care provided? And what about the effects on the person undergoing testing and their family members? What did testing mean to them? And how do they now navigate through this whole process?” said Dr. DeMarco.
She is a clinical chemist at St. Paul’s Hospital, Providence Health Care and a clinical professor in UBC’s Department of Pathology and Laboratory Medicine. She also leads the national AD biomarker testing program, which is accessible to individuals across Canada.
Recognizing the changing diagnostic landscape for AD, Dr. DeMarco and her collaborators led an observational research study that sought to understand how biomarker testing altered medical care, how patients and their families felt about going through the whole process, and what testing meant for them.
Called IMPACT-AD, it was the first of its kind in the world and was funded in part by Women’s Brain Health Initiative and Brain Canada.
Dr. DeMarco and her team conducted interviews with B.C.-based patients who had undergone the biomarker testing, as well as a family member or close friend. One of the first questions considered was the state of mind of the person about to undergo testing. An AD diagnosis is life altering, and it would be natural to think that someone would approach a definitive diagnosis with a sense of dread. But that’s not what the researchers discovered.
“Surprisingly, we found that participants reported the decision to undergo testing as an ‘easy’ decision, motivated by their desire to better understand why they were experiencing cognitive changes.”
Her team’s paper, published in April 2024 in Alzheimer's & Dementia: The Journal of the Alzheimer's Association, reports that 90% of patients rated their decision to undergo testing as “easy.”
ACCESS TO TESTING
It is important to understand that biomarker tests are not done on just anyone who wants to find out if they may one day develop AD. Testing is only accessible to people who are already showing signs of cognitive decline and have discussed the test with a doctor who specializes in disorders like AD.
“People undergoing testing are individuals who are seeing a specialist because they've had challenges with their brain health and are actively seeking a confident diagnosis as to why they were experiencing these challenges,” said DeMarco.
“Patients and family members, through the IMPACT-AD research study, explained that testing was helpful in relieving the part of their anxiety around not having a confident diagnosis. They also expressed that having that confident diagnosis was helpful in planning for the future.”
Quoting from the research study:
Post-disclosure, the majority (82%) reported overall positive feelings from having greater certainty and the ability to plan ahead, and results spurred them to adopt/continue healthy behaviours such as exercise (84%) and cognitive activities (54%).
Care partners expressed relief from having more diagnostic certainty, increased appreciation of future caregiving responsibilities, and a desire to connect with support resources.
ACCURACY IMPROVES CARE
An accurate diagnosis also means the patient does not need to keep undergoing tests and it allows healthcare practitioners to better plan the road ahead.
“Having it increases a physician’s confidence in making the diagnosis which could in turn impact how they manage the disease moving forward,” said Dr. Saskia Sivananthan, Partner and Head of Strategy, Brainwell Institute and an affiliate professor at McGill University.
“While there is no cure for Alzheimer’s disease, there is much, much more that can be done with what is communicated to the patient. Lifestyle changes are crucial even at the early stage of the disease, and more evidence is showing that changing your diet, exercise, increasing social connectivity, and mindfulness does slow the progression of the disease,” added Dr. Sivananthan.
HOW SEX AND GENDER PLAY A PART
Given that AD affects women at a much higher rate than men, researchers are increasingly taking sex differences into consideration as part of their studies, trying to understand the reasons behind the disparity.
Dr. Carmela Tartaglia of the University of Toronto says there is little conclusive evidence that the biomarker tests have a gap in accuracy between the sexes.
“I would say we don't think that they’re ineffective in men versus women, or women versus men. I think the jury is still out on whether they work, equally well. The difference may be nominal,” said Dr. Tartaglia, a professor,, Tanz Centre for Research in Neurodegenerative Diseases at U of T and Co-director of the UHN Memory Clinic .
In their surveys, the IMPACT-AD team found that impacts from testing were largely similar between women and men.
One difference observed was that as a result of biomarker testing, female family members and friends expressed greater recognition of their likely future role as a caregiver. They also tended to ask more questions about caregiving resources, a reflection perhaps of the reality that far more women than men are caring for a person with dementia.
BETTER SUPPORT
An important product of the IMPACT-AD study was a better realization of the needs of people who have received an AD diagnosis, along with their care partners.
“It’s wonderful what we’ve been able to learn directly from the patients and their family members, as this in turn helps us improve the process and resources for future patients and family members undergoing testing,” said Dr. DeMarco.
The researchers discovered that patients and family members valued the time their doctor took to fully inform them about the test so that they approach the process with full knowledge of the implications.
It is also important for those who receive a diagnosis of a neurodegenerative disease to be provided with essential information to help guide them.
“Participants told us that after both pre- and post-test counselling visits with their doctor, they valued having information they could take home with them. To support these needs, we developed guides – in partnership with patients, family members, and healthcare professionals – to support common questions related to biomarker testing, the meaning of test results, and available community resources for persons diagnosed with Alzheimer’s disease or a related disorder,” she said.
These resources are all publicly available on the IMPACT-AD website: impactad.org/resources.
Dr. DeMarco said she is grateful to Women’s Brain Health Initiative, Brain Canada, and other supporters, given that this kind of project can be challenging to fund. It does not have the novelty of a new discovery, rather it is all about how to put a discovery into clinical practice.
“It has such a huge impact on patients and family members. It is wonderful that our funding partners recognized the importance of implementation research, like the IMPACT-AD study, which aims to directly and immediately improve care for people with Alzheimer’s disease.”
IMPACT-AD has already moved on to the next step, expanding beyond the borders of British Columbia. In collaboration with the Canadian Consortium on Neurodegeneration in Aging, the team is now gathering and analyzing new data from participants across Canada.
The IMPACT-AD study was supported with a grant from Brain Canada through the Canada Brain Research Fund with the financial support of Health Canada, Michael Smith Health Research BC, the University of British Columbia’s Faculty of Medicine and the Djavad Mowafaghian Centre for Brain Health, Women’s Brain Health Initiative, and the St. Paul’s Foundation.
Source: Mind Over Matter V19