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Senior Citizens Can't Walk and Chew Gum: Study
Implies It's No Joke
Brain scan researchers say they found what causes
seniors to be distracted
By Tucker Sutherland, editor
Feb. 6, 2006 – Okay, fellow senior citizens, if you
can read this without getting distracted, you will learn the reason some
scientist say we have "reduced ability to ignore distracting or
irrelevant information." Well, let me tell you what they say right up
front – "Activity in the medial frontal and parietal regions stays
turned on while activity in the dorsolateral prefrontal cortex
decreases." There you have it, if I haven't lost you to some
distraction.
This study looks at brain function in young,
middle-aged and older adults. The scientists say they have identified
changes in brain activity that begin gradually in middle age – and which
"may explain why older adults find it difficult to concentrate in busy
environments and filter out irrelevant information."
"It's known that older adults are more easily
distracted. We think we've found a mechanism in the brain to explain
this and generated new insight into when in the lifespan these brain
changes begin to occur," says senior scientist and lead author Dr.
Cheryl Grady of The Rotman Research Institute.
The study reinforces a cautionary message to aging
adults, says Dr. Grady:
"Older adults should try to reduce distractions in
their environment and concentrate on one key attentional task at a time.
It may be as easy as turning down the radio when reading, or staying off
the cell phone when driving a car."
Note: I hope Dr. Grady will take a closer
look at those "distracted drivers" talking on cell phone while they try
to concentrate on driving. I see lots of them everyday but I don't think
one has been a senior citizen.
While previous studies have used functional
magnetic resonance imaging (fMRI) to look at how brains function
differently in young and old adults, and patients with Alzheimer's
Disease, this is the first time investigators have used fMRI on normal,
healthy middle-aged adults, as well as young and old adults, to
understand how brains are changing in the in-between years, according to
the report.
Investigators gave a series of memory tasks to the
three age groups to assess if age-related changes in brain function are
task-specific, or generalized across a number of regions during memory
tasks.
The findings, they say, add to the growing body of
science that implicates two regions in the frontal lobes that gradually
shift into a seesaw imbalance – causing older adults to become less
efficient in inhibiting distracting information.
In younger adults, activity in the dorsolateral
prefrontal cortex (associated with tasks that require concentration,
such as reading) normally increases during the task, while activity in
the medial frontal and parietal regions (associated with non-task
related activity in a resting state, such as thinking about yourself,
what you did last night, monitoring what's going on around you) normally
decreases.
Note: Again, there seems to be some
confusion. Maybe they got the brain scans switched. As a senior citizen,
I can tell you what I did last night, but my four children always seemed
a little fuzzy in trying to tell us what they did the night before.
Starting in middle age (40-60 years), Dr.
Grady's team says that this seesaw pattern begins to break down during
performance of memory tasks.
Activity in the medial frontal and parietal regions
stays turned on while activity in the dorsolateral prefrontal cortex
decreases. The imbalance becomes more pronounced in older adults (65+),
which could explain their reduced ability to ignore distracting or
irrelevant information, she says.
"Our fMRI scanning reveals that middle age
represents the transition between the patterns observed in youth to that
found in old age. The seesaw imbalance in the two frontal lobe areas is
not as significant as in older adults, but the functional changes are
detectable by middle age."
The study
Twelve young adults (20-30 years), 12 middle-aged
adults (40-60 years) and 16 older adults (65-87 years) participated in a
series of memory tasks. The groups all had an average of post-secondary
education.
Note: So, senior citizens, before you get depressed and
sick with worry about the "seesaw imbalance" in your frontal lobe areas,
please, note that these scientist studied only 16 senior citizens.
Here are the tests they gave them. The first set of
memory exercises involved encoding – looking at common nouns and
pictures of objects of different sizes. By pushing one of two buttons,
participants could decide whether words were printed in capital letters
or lower case, whether pictures presented were large or small, and
whether the pictures or words corresponded to living or nonliving
entities. This tested their semantic and perceptual judgment.
Participants were then administered scanned
recognition tests made up of words written in lowercase letters,
including words to describe the pictures they had seen, to assess
semantic and perceptual recall.
During all the memory tasks, their brains were
scanned using fMRI which constructs computerized images of brain
structures and pinpoints the areas being activated during a memory task.
While investigators say they found that middle-aged
adults performed just as accurately as younger adults on encoding and
recognition tasks, brain scanning revealed that functional changes (i.e.
the "seesaw imbalance") are starting to appear as early as middle age,
although the changes are gradual and don't translate into a noticeable
change in memory performance for that age group.
Scanning also revealed that functional brain
changes and associated deficits in cognitive performance (i.e. lower
accuracy scores particularly in recall tests) become more pronounced
after the age of 65.
Indeed, the altered activity level in medial
frontal and parietal regions in older adults is similar to that seen in
patients with Alzheimer's, although less pronounced, says Dr. Grady.
Overall, findings confirmed that age-related
changes in brain function are happening across various memory tasks and
progress in a linear fashion as adults age.
Because most of the participants in the study were
fairly well educated, the finding of brain changes without accompanying
behavioural changes in the middle-aged group may reflect what previous
scientific studies have termed the "protective effect" on behaviour.
"Higher education levels may allow for some
redundancy of brain function or compensation that leads to preserved
performance in middle-aged adults, at least on some tests, despite
altered brain activity," says Dr. Grady.
About the Study
The findings, by scientists at The Rotman Research
Institute at Baycrest and the University of Toronto, are reported in the
February 2006 issue of the Journal of Cognitive Neuroscience (Vol. 18,
No. 2).
The study was supported by a grant from the
Canadian Institutes of Health Research. Dr. Grady's research team
included Dr. Randy McIntosh, Dr. Gordon Winocur, Mellanie Springer and
Donaya Hongwanishkul.
Baycrest is an internationally-recognized
healthcare and research facility for aging adults, with a focus on brain
functioning and mental health.
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