Tests can predict risk of dementia decade before onset: study
© Illustration by The Telegram
One test studied as a predictor of cognitive problems matches numbers with symbols.
Toronto — Mentally scrambling for words, being unable to recall names or losing track of everyday items like car keys can make a person anxious about whether such mental blips are normal for their age or a harbinger of dementia.
Now researchers say two simple tests have the potential to answer the question, providing an accurate prediction of whether a senior has an elevated risk of developing Alzheimer’s — or indeed any type of dementia — up to 10 years in advance of diagnosis.
“They can be aware that before they actually have a diagnosis there are ways to identify whether or not they’re likely to go on and develop dementia,” said Dr. Mary Tierney, principal investigator of a 10-year study of more than 1,500 healthy men and women, aged 65 and older.
To conduct the study, published online by the Journal of Alzheimer’s Disease, researchers administered the standard battery of neurocognitive tests with the aim of teasing out which examinations would end up being predictive of patients later diagnosed with dementia.
Tierney, director of geriatric research at Sunnybrook Health Sciences Centre in Toronto, said two tests stood out: the delayed word recall test and one in which subjects must match up numeric figures with symbols.
In the first test, subjects are told a list of 15 unrelated words, which is repeated five times. After being told a list of 15 different words, patients are asked to recall as many words from the initial list as possible. In the second test, they must draw the symbols that correspond to numbers they have been shown.
“Poor performance on those two tests — obviously not really bad performance, but lower than what you would expect — would indicate their risk of developing dementia 10 years later,” she said.
The study found that for every additional word recalled on the memory test, there was an 18 per cent drop in the risk of developing dementia within 10 years; for every additional symbol provided in the digit-symbol test, there was a five per cent decline in risk.
“A big problem for a lot of people, especially older people, is they’re wondering: I’m noticing changes in my memory or I’m noticing changes in myself. Are these changes just because I’m anxious or are they normal aging? Is this something I should worry about?” said Tierney.
While cognitive tests typically given by general practitioners can identify patients who are showing obvious symptoms of dementia, she said they are not refined enough to recognize those in the preliminary stages of mental decline.
“So when somebody could be in the early stages, they wouldn’t pick them up. They have to use these more demanding, challenging tests to pick up something that’s going to happen 10 years hence.”
Although there are no drugs to treat early Alzheimer’s, vascular dementia or other forms of the brain-ravaging disease, Tierney said lifestyle changes such as regular exercise, intellectual and social stimulation and a healthy diet have been shown in numerous studies to stave off the onset of symptoms.
“They can be aware that before they actually have a diagnosis there are ways to identify whether or not they’re likely to go on and develop dementia.” Dr. Mary Tierney
Knowing that a person has an elevated risk of dementia could spark changes, she said. “At that point, when they’re still cognitively intact and able to function, they may say: ‘This is a motivator for me. Maybe I’ve not been as active as I should, maybe I should get out instead of just staying inside watching television; get more engaged with people.’
“So it could be a trigger to take advantage of what we know may delay the onset.”
The idea isn’t that people who experience what some call “Alzheimer’s moments” should seek out these sophisticated tests typically provided by dementia specialists like neurologists, she said.
“I think if they have problems that they are experiencing, if there’s a concern, talk to your family doctor. And then if (other conditions) can be ruled out, then possibly pursue it.”
In another study published in the Journal of Alzheimer’s Disease, Tierney’s research team found that too much strenuous exercise throughout a woman’s life may not be a good thing when it comes to Alzheimer’s and other dementias.
The researchers followed 90 post-menopausal women for a decade and found that those who spent more time per week engaging in strenuous exercise like aerobics, running and playing basketball, from high school onwards, had lower neurocognitive test scores than those who spent less time.
“It’s already been established that moderate activity probably delays the onset (of dementia),” she said. “And in fact, we found the more moderate activity the woman engaged in, the better her cognitive scores, so it supports that.
“However — and this actually was quite surprising — for every single test, the more strenuous, the lower the performance … on these tests that predicted dementia.”
Strenuous exercise can diminish a woman’s level of estrogen, a hormone believed to protect against dementia.
While more research is needed on larger groups of women to confirm the findings, Tierney said women who spend a lot of time doing rigorous exercise conceivably could be harming their brains.
“Younger women might want to think about what they’re doing when they initially engage in maybe two or three marathons a year,” she said.
“Definitely we can push them to more and more moderate (exercise). That’s fine, that’s wonderful … But we should not necessarily be pushing women in particular to more and more strenuous.”