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New Tests Could Offer Early Alzheimer's Warning

MRI Scan of human brain
From the WebMD Archives

The hunt is on for new and earlier ways to detect Alzheimer's.

Scientists are looking for clues in your eyes, your speech -- even the way you smell as they try to uncover possible ways to identify early warning signs of the disease, the most common form of dementia.

There is no cure for this debilitating and life-altering disease, which erodes a person’s memory, thinking and behavior.

But scientists believe if they can figure out how to identify it sooner, they may be able to use medications, lifestyle changes, or other strategies to fight it before it has caused irreversible brain damage.

More than 5 million Americans have Alzheimer’s disease, and the Alzheimer’s Association says that number could be as high as 16 million by 2050. That means every 66 seconds, someone in the U.S. develops the disease.

There’s no one test to diagnose Alzheimer’s. But changes in the brain related to the disease can begin years before any signs of it, and there is now a focus on looking for those early warning signs.

Be Aware of Warning Signs

Doctors at Cedars-Sinai Medical Center in Los Angeles have developed the first eye test for Alzheimer’s.

The researchers say results of a study in the U.S. and Australia show technology that uses light to peer into the eye may be the key to detecting the debilitating disease 15 to 20 years before doctors now can diagnose it.

“The back of the eye, the retina, is an extension of the brain. The key observation from our group was that the hallmark of Alzheimer’s disease -- amyloid plaque -- is one of the first signs that develops in Alzheimer’s, and it not only occurs in the brain, but also in the retina,” explains Keith L. Black, MD, chairman of the Cedars-Sinai Department of Neurosurgery.

Black says the test takes about 20 minutes. It is noninvasive, affordable, and has been highly accurate in determining if someone does not have the disease and also has a good track record for being able to tell patients when they do have it.

Investigators are now following the progress of plaques in some patients as part of the study. The test is being used in clinical trials at hospitals in the U.S. and Australia but is not yet available to the general public.

Sense of Direction

A study published in August 2017 says losing the ability to navigate could be another early sign of Alzheimer’s.

In the study, researchers showed patients a route and asked them to reproduce it while remembering turns and places.

“These assessments have included real-world navigation tasks out on the street or in hospital corridors and also using virtual environments -- computer mock-ups of real world environments,” says Scott Moffat, PhD, who co-authored the paper. He is an associate professor in the school of psychology at the Georgia Institute of Technology in Atlanta.

“In Alzheimer’s disease, ‘wandering’ or ‘getting lost’ is a common feature and complaint of patients and caregivers alike,” he says. “So one reason why we think navigation may be affected early in aging and dementia is because we can observe it behaviorally.”

Moffat says there is a second reason, too.

“In the future, we think that navigation assessment may become a good early marker for Alzheimer’s disease because it depends on the same brain systems that are most affected in Alzheimer’s disease,” he explains.

Navigation could also be used to test how well drugs and behavioral treatments are working, he says. The downsides of navigation assessment, researchers say, are a lack of one standard test to find out how well someone can navigate and that those skills vary a lot between people.

From Smelling … to Speech

Testing the sense of smell by identifying and naming odors might also give an early warning sign of progressing to Alzheimer’s disease. Researchers at McGill University in Montreal tested older people thought to be more likely to get Alzheimer’s disease either because a parent or several siblings had been diagnosed with it.

Using a scratch-and-sniff booklet, they associated odor identification to Alzheimer’s disease-related proteins in brain and spinal fluid. The research found that a lessened ability to identify odors was associated with lower thinking and memory skills, older age, and brain shrinkage.

Researcher Marie-Elyse Lafaille-Magnan, a doctoral candidate involved in the study, says odor identification is helpful to study because it involves many parts of the brain.

The Alzheimer’s Association cites promise in other studies identifying possible precursors to Alzheimer’s disease, including:

  • Hearing loss could show that thinking abilities are worsening in older adults, including processing new information, thinking flexibly, and brain, eye, and hand coordination while processing information.
  • Another study showed that changes in everyday speech -- including the use of short sentences, more pronouns, and pauses like "um" and "ah” --were connected to early mild impairment in thinking skills, which can be a precursor to Alzheimer's disease.
  • And another study found that older adults have a high risk for memory and thinking problems after being hospitalized in emergency or urgent admissions, but not for elective or scheduled surgeries.

Value in Early Diagnosis

There isn’t a cure for Alzheimer’s disease, so what is the value of knowing you might get the disease -- years before you actually do?

For researchers, it’s about prevention.

“The better we understand the sequence of how things change over time and can identify biomarkers that are early markers of brain changes, the better we can take advantage of them in prevention trials,” Lafaille-Magnan explains.

The Alzheimer's Association says early detection allows people a better chance of benefiting from treatment, more time to plan for the future, more chances to take part in clinical drug trials, and a chance to decide about care, living options, and financial and legal matters.

Black says Alzheimer’s disease develops about 20 years before you lose memory and have thinking and behavior problems. So by the time you show symptoms, you have already lost brain cells and brain connections.

“If you could intervene with a drug earlier, before you have lost those brain cells, you may actually be able to have a better therapeutic outcome,” he says.

But Jeffrey Sherman, MD, a family practice doctor in Washington, D.C., says in the real world, testing for early signs of Alzheimer’s could be complicated.

“It’s complex,” he says. “Would the knowledge of having an increased risk change what they want to accomplish in the next 5 years of their life? It’s not guaranteeing that they will develop it, but if they do, would they change their family situation or how they set up their finances or their general plans in some other way? If so, then we could look at it.”

Sherman says he likes to talk with patients about ways to make the most of their mental capacities. Stressing there are no guarantees, he says he talks about advantages of exercising and keeping minds active with crossword puzzles, sudoku games, playing bridge, or working.

Researchers in the study about navigational abilities recommend that people don’t always rely on GPS systems to get them where they need to go, but instead use their own navigation ability to exercise that part of their brain.

Black agrees that lifestyle habits can play an important role in the progression of the disease.

“If a patient knows they are on the road to develop Alzheimer’s, we know modifying diet to a Mediterranean diet, exercising, moderating stress, getting 8 hours sleep a night -- all of these things are now showing in more and more scientific studies that they may play a very important role in slowing progression to the symptomatic phase of the disease,” he says.

Micronutrients like curcumin, omega-3s, and flavonoids could also help, he says.

If you would like to learn more about Alzheimer's and dementia research studies in your area that are recruiting volunteers, visit www.alz.org/research/clinical_trials/find_clinical_trials_trialmatch.asp