Alzheimer's, Dementia & Mental Health
Mild Memory Loss – Senior Moments – Not a Part of
Normal Aging Says New Research
‘Our study finds that Alzheimer’s disease and
related dementias are the root cause of virtually all loss of cognition
and memory in old age’
Sept. 15, 2010 - Simply getting older is not the
cause of mild memory lapses often called “senior moments,” according to
a new study by researchers at the Rush Alzheimer’s Disease Center. The
study found that even the very early mild changes in memory that are
much more common in old age than dementia are caused by the same brain
lesions associated with Alzheimer’s disease and other dementias.
“The very early mild cognitive changes once thought
to be normal aging are really the first signs of progressive dementia,
in particular Alzheimer’s disease.” said Robert S.Wilson, PhD,
neuropsychologist at Rush University Medical Center.
“The pathology in the brain related to Alzheimer’s
and other dementias has a much greater impact on memory function in old
age than we previously recognized.”
The study, published in the September 15, 2010,
online issue of Neurology, the medical journal of the American
Academy of Neurology, involved over 350 nuns, priests and brothers who
participated in Rush’s Religious Orders Study.
The participants completed up to 13 years of annual
cognitive testing. After death, the brains were examined for the lesions
associated with dementia: neurofibrillary tangles, cerebral infarction
(stroke), and Lewy bodies.
Researchers looked at the rate of change in
cognitive function over time. The last four to five years of life showed
a very rapid decline. The preceding years showed a much more gradual
decline that would be described as normal aging.
As expected, pathologic lesions (wounds) were
related to the rapid decline, but researchers were somewhat surprised to
find the pathology was very strongly predictive of the mild changes in
cognitive function.
Higher tangle density adversely affected all forms
of cognition at all trajectory points. Both Lewy bodies and stroke
approximately doubled the rate of gradual memory decline, and almost no
gradual decline was seen in the absence of lesions.
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About Lewy Body Proteins
In the early 1900s, while researching Parkinson's
disease, the scientist Friederich H. Lewy discovered abnormal protein
deposits that disrupt the brain's normal functioning.
These Lewy body
proteins are found in an area of the brain stem where they deplete the
neurotransmitter dopamine, causing Parkinsonian symptoms. In Lewy body
dementia, these abnormal proteins are diffuse throughout other areas of
the brain, including the cerebral cortex.
The brain chemical
acetylcholine is depleted, causing disruption of perception, thinking
and behavior. Lewy body dementia exists either in pure form, or in
conjunction with other brain changes, including those typically seen in
Alzheimer's disease and Parkinson's disease.
>>
More at Lewy Body Dementia Association
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“Our study finds that Alzheimer’s disease and
related dementias are the root cause of virtually all loss of cognition
and memory in old age. They aren’t the only contributing factors; other
factors affect how vulnerable we are to the pathology and to its
effects.
But the pathology does appear to be the main force that is
driving cognitive decline in old age,” said Wilson.
According to Wilson, recognizing that the earliest
changes in memory are related to Alzheimer’s pathology can lead to early
diagnosis and will be critical information if a treatment is developed
that can alter the pathologic course of the disease.
The study was supported by the National Institute
on Aging. Co-authors include Sue Leurgans, PhD; Patricia Boyle, PhD; Dr.
Julie Schneider and Dr. David Bennett.
The Rush Alzheimer's Disease Center (RADC) is one
of 29 Alzheimer's disease research centers across the country designated
and funded by the
National Institute on Aging.
The center is dedicated to reducing
disability due to Alzheimer's disease and other age-related conditions
through research on the treatment and prevention of disease for this and
future generations. Since 1985, the RADC has provided services to more
than 5,000 Alzheimer's patients and their families through its
outpatient clinic.
