Biomarkers and early diagnostic tools may eventually provide doctors with the window they need treat Alzheimer’s before people exhibit symptoms.
There’s no cure for Alzheimer’s yet.
But even if there were, it might be difficult to tell who could benefit from the remedy.
So while some researchers work to develop treatments to slow or reverse the loss of cognitive abilities, others are working on developing ways to diagnose Alzheimer’s and other causes of dementia as early as possible.
They’re beginning to make some progress.
“We would like to be able to develop drugs to prevent Alzheimer’s disease, but to do that we have to be able to find the people who are at risk of Alzheimer’s before they develop symptoms,” Jim Hendrix, director of global science initiatives at the Alzheimer’s Association, told Healthline.
Telling the people with Alzheimer’s apart from those with other impairments is critical to developing drugs that can target the different causes of the condition.
Getting diagnoses right is also key to ruling out cognitive issues caused by treatable conditions — the Alzheimer’s Association cites depression, drug interactions, thyroid issues, and excessive alcohol consumption. And it can allow for better planning regarding living situations, career decisions, or even participating in clinical drug trials.
But advancing along the road to a cure or treatment is the ultimate goal.
“There’s a lot of hope and optimism that if we can catch it earlier we might be able to stabilize or, in an ideal world, reverse it,” said David Kaufman, PhD, a professor of clinical neuropsychology at Saint Louis University. “If we catch it early, we might be able to learn more about what interventions could help and what changes could undo and reverse some of that damage.”
Right now, a diagnosis of Alzheimer’s generally only comes after someone has been showing signs of memory impairment, meaning they’re usually already experiencing life-altering impacts. “When it’s progressed to that stage, there’s very little that can be done to manage it,” Kaufman told Healthline.
The question is, can we develop something that can manage (or prevent) it if Alzheimer’s is caught much earlier? The first step in answering that is knowing how to catch it early.
A couple recent studies took on that challenge.
A team at Ohio State University has discovered biomarkers — changes in proteins in the spinal fluid and blood of people with Alzheimer’s — that could help lead to a diagnosis and predict how severe the disease may become in specific cases. According to a study published last month, the longer, harder, and more clustered these proteins were, the greater the severity of the condition.
In another recently published study, researchers used a large electromagnetic coil to stimulate certain nerve cells in the brain through the scalp, and measure how the brain conducted the electrical signals. They were able to distinguish brains with Alzheimer’s from healthy brains with 87 percent accuracy. They were also able to distinguish brains with frontotemporal dementia (which causes 10 to 15 percent of dementia cases) from healthy brains with 86 percent accuracy, and brains with Alzheimer’s from those with frontotemporal dementia with 90 percent accuracy.
Both of these study results reflect the promise of new technologies and techniques for improving Alzheimer’s diagnoses. But they also reflect the limits of our current advances, experts said.
“The numbers are pretty impressive,” Kaufman said of the electromagnetic coil study. “But for these to work, patients already had to be showing some signs of early Alzheimer’s disease,” making the method not very helpful for early diagnoses.
The other study, he said, appeared to do somewhat well at differentiating people with moderate cases of Alzheimer’s from those with severe cases, though not amazingly well. But the study, which looked at a biomarker other studies have worked with, but on a much smaller scale, does suggest there may be benefits to improving past techniques.
“The closer we look, the more we might be able to better find differences in who is going to develop Alzheimer’s and who isn’t,” Kaufman said. “If we are able to get higher and higher resolution of the physical properties of this, then we may be able to learn more about what’s causing those chemicals to be out of whack and get disrupted.”
There may be nonphysical or nonbiological signs that Alzheimer’s is imminent — though they’re less likely to help with developing cures. Kaufman has been working with colleagues to try to determine which cognitive markers slip before others.
Attention-switching — like when a subject is told to respond a certain way to something and then to respond a different way to the same thing — seems to be one of them.
“It better predicts the eventual development of Alzheimer’s than just about any other cognitive ability that we’ve studied,” Kaufman said, adding that these cognitive markers alone wouldn’t be enough for a diagnosis.
Other studies have focused on detecting the presence of amyloid plaques, a sticky buildup found in the brains of people with Alzheimer’s.
Screening people in the general population — and determining that Alzheimer’s is the cause of the coming dementia in their future — could allow doctors to halt development of the disease with a treatment that prevents amyloid buildup.
But that won’t be easy to do. Hendrix is working on a study to evaluate how PET scans for brain amyloid affect patient outcomes. Its preliminary data show that 30 percent of subjects who have been diagnosed with dementia, and 45 percent of those diagnosed with mild cognitive impairments, don’t have amyloid buildup. And thus, don’t have Alzheimer’s.
That’s further evidence that at this time we can’t differentiate the causes of dementia. “That means the tools we’re using for diagnoses are lacking, and we need better tools,” Hendrix said.