Jun 14, 2017

Cognitive tests can detect early Alzheimer’s disease in older adults without symptoms

Early detection could be a powerful tool to manage Alzheimer’s. Early detection gives people time to try different medications or interventions that may slow the progression of Alzheimer's disease.


 We have reached the point where cognitive tests are able to detect early Alzheimer’s in people without symptoms

We have reached the point where cognitive tests are able to detect early Alzheimer’s in people without symptoms.



Alzheimer's Reading Room

A simple baseline evaluation by a qualified neuropsychologist at age 50 or 60 could be used as a way to track whether someone is experiencing a true decline in cognition as they age.

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Detecting Alzheimer’s Disease Before Symptoms Emerge

Long before symptoms of Alzheimer’s disease become apparent to patients and their families, biological changes are occurring within the brain.


Amyloid plaques, which are clusters of protein fragments, along with tangles of protein known as tau, form in the brain and grow in number, eventually getting in the way of the brain’s ability to function.

These biological changes can be detected early in the course of Alzheimer’s disease through positron emission tomography (PET) scan or cerebrospinal fluid analysis.

A new led by Keck Medicine of USC neuropsychologist Duke Han, PhD, associate professor of family medicine (clinical scholar) at the Keck School of Medicine of the University of Southern California suggests that cognitive tests are also able to detect early Alzheimer’s in people without symptoms.


“In the last decade or so, there has been a lot of work on biomarkers for early Alzheimer’s disease.” There are new imaging methods that can identify neuropathological brain changes that happen early on in the course of the disease.

Putting neuropsychological measures to the test
  • A meta-analysis of 61 studies to explore whether neuropsychological tests can identify early Alzheimer’s disease in adults over 50 with normal cognition was performed
  • The study found that people who had amyloid plaques performed worse on neuropsychological tests of global cognitive function, memory, language, visuospatial ability, processing speed and attention/working memory/executive function than people who did not have amyloid plaques.

  • The study also found that people with tau pathology or neurodegeneration performed worse on memory tests than people with amyloid plaques. Amyloid plaques and tau pathology were confirmed by PET scan or cerebrospinal fluid analysis.
"The presumption has been that there would be no perceivable difference in how people with preclinical Alzheimer’s disease perform on cognitive tests. This study contradicts that presumption."

Routine cognitive screenings: A new normal?

The study results provide a solid argument for incorporating cognitive testing into routine, annual checkups for older people.
“Having a baseline measure of cognition before noticing any kind of cognitive change or decline could be incredibly helpful because it’s hard to diagnose early Alzheimer’s disease if you don’t have a frame of reference to compare to.” 
“If people would consider getting a baseline evaluation by a qualified neuropsychologist at age 50 or 60, then it could be used as a way to track whether someone is experiencing a true decline in cognition in the future.”


Early detection could be a powerful tool to manage Alzheimer’s giving people precious time to try different medications or interventions that may slow the progression of the disease early on.
“While there’s no cure for Alzheimer’s disease, the earlier you know that you’re at risk for developing it, the more you can potentially do to help stave off that diagnosis in the future,” Han said. 
“For example, exercise, cognitive activity and social activity have been shown to improve brain health.”

The study, which was published in Neuropsychology Review

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ABOUT THE KECK SCHOOL OF MEDICINE OF USC

Founded in 1885, the Keck School of Medicine of USC is among the nation’s leaders in innovative patient care, scientific discovery, education, and community service. It is part of Keck Medicine of USC, the University of Southern California's medical enterprise, one of only two university-owned academic medical centers in the Los Angeles area.

In 2017, U.S. News & World Report ranked Keck School of Medicine among the Top 40 medical schools in the country.

For more information, go to keck.usc.edu.

Citation

Detectable Neuropsychological Differences in Early Preclinical Alzheimer’s Disease: A Meta-Analysis

Duke Han, S., Nguyen, C.P., Stricker, N.H. et al. Neuropsychol
Rev (2017). doi:10.1007/s11065-017-9345-5