SIMPLE TEST CAN HELP DETECT ALZHEIMER'S BEFORE DEMENTIA SIGNS SHOW
York University
researchers say a simple test that combines thinking and movement can help to
detect heightened risk for developing Alzheimer's disease in a person, even
before there are any telltale behavioural signs of dementia
Faculty of Health
Professor Lauren Sergio and PhD candidate Kara Hawkins who led the study asked
the participants to complete four increasingly demanding visual-spatial and
cognitive-motor tasks, on dual screen laptop computers. The test aimed at
detecting the tendency for Alzheimer's in those who were having cognitive
difficulty even though they were not showing outward signs of the disease.
"We included a
task which involved moving a computer mouse in the opposite direction of a
visual target on the screen, requiring the person's brain to think before and
during their hand movements," says Sergio in the School of Kinesiology
& Health Science. "This is where we found the most pronounced
difference between those with mild cognitive impairment (MCI) and family
history group and the two control groups."
Hawkins adds, "We
know that really well-learned, stereotyped motor behaviours are preserved until
very late in Alzheimer's disease." These include routine movements, such
as walking. The disruption in communication will be evident when movements
require the person to think about what it is they are trying to do.
For the test, the
participants were divided into three groups -- those diagnosed with MCI or had
a family history of Alzheimer's disease, and two control groups, young adults
and older adults, without a family history of the disease.
The study, Visuomotor
Impairments in Older Adults at Increased Alzheimer's Disease Risk, published in
the Journal of Alzheimer's Disease, found that 81.8 per cent of the
participants that had a family history of Alzheimer's disease and those with
MCI displayed difficulties on the most cognitively demanding visual motor task.
"The brain's
ability to take in visual and sensory information and transform that into
physical movements requires communication between the parietal area at the back
of the brain and the frontal regions," explains Sergio. "The
impairments observed in the participants at increased risk of Alzheimer's
disease may reflect inherent brain alteration or early neuropathology, which is
disrupting reciprocal brain communication between hippocampal, parietal and
frontal brain regions."
"In terms of
being able to categorize the low Alzheimer's disease risk and the high
Alzheimer's disease risk, we were able to do that quite well using these
kinematic measures," says Hawkins. "This group had slower reaction
time and movement time, as well as less accuracy and precision in their
movements."
Hawkins says the
findings don't predict who will develop Alzheimer's disease, but they do show
there is something different in the brains of most of the participants
diagnosed with MCI or who had a family history of the disease.
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