Bringing our brain
into blossom
by Laurien Albeda
For decennia, researchers have been working to
understand the complex workings of cognitive reserve
– a reserve that makes our brain flourish despite
Alzheimer ’s disease.Their efforts are starting to pay off.
Illustration by Pelin Esnaf
T
he sun burns
mercilessly in the
sky. The tropical
heat has dried out
the stretch of land beneath
it and warmed up the rocky
hills that dominate the view.
Some patches of dry grass
are scattered across it. In the
middle of this landscape, a
sudden flock of yellow catches
the eye. In the middle of this
desert-like place, a blooming
flower is proudly showing off
its bright colours.
This is what Rik
Ossenkoppele, postdoctoral
researcher of neuropsychology
at Alzheimer Centre of VUMC,
came across while travelling
through Madagascar. The
pachypodium rosulatum or
‘elephant’s foot plant’ he saw,
can survive and even blossom
in extremely dry conditions.
Its secret weapon is the water
storage at the bottom of the
plant. Ossenkoppele’s voice
sparks with enthusiasm as he
speaks of the comparison.
“That, I thought, is exactly what
cognitive reserve is.”
The neuropsychological
concept of cognitive reserve
was proposed more than thirty
years ago and continues to
captivate researchers. It has
become clear that a better
understanding of its working
could help in the quest of
fighting Alzheimer and various
other diseases that cause
dementia. Dementia leads
to a relatively great decrease
in quality of life. And as the
Dutch population ages, more
people are suffering from the
disease. Research on cognitive
reserve is starting to reveal
ways to postpone the effects of
Alzheimer’s disease.
Blooming flower
In 1989, a neurologist called
Robbert Katzman and his
research team describe cases
in which they research the
brains of elderly women postmortem. The women, who had
shown no signs of Alzheimer
during their lives, were
revealed to have advanced
Alzheimer pathology in their
brains. One of the explanations
is that the damage can be
observed long before the
cognitive skills of a person start
to decline. “Another possible
explanation is cognitive
reserve.” says Ossenkoppele,
“This reserve could help our
brain to handle the damage
caused by Alzheimer’s disease
and delay symptom onset.”
“
Cognitive reserve could
help our brain to delay
the onset of Alzheimer’s
disease symptoms
”
Alzheimer’s disease is
the most common form
of dementia. 70% of the
people with dementia are
diagnosed with Alzheimer.
The illness causes neurons
to decay and the brain to
shrink. As a result, a patient
first has trouble memorising
(new) information and at
a later stage has trouble
performing even the
smallest of daily activities.
Cognitive reserve acts like the water
reservoir does for the elephant’s foot plant
photo: heinonlein / Wikimedia Commons
In other words, the
damaged brain is like the
dried-up land in Madagascar.
The flowers represent the
cognitive skills that a person
can perform. The cognitive
reserve is the water storage,
nurturing the blossom.
As the elephant’s foot
plant feeds its flowers, it draws
water from its sponge-like
storage. It can suck up water
from the area closest to the
transporting tissue. But it
can also use the water from
other parts of the sponge.
Yaakov Stern, professor of
Neuropsychology at the
Colombian UMC describes
something similar happening in
the brain. Cognitive reserve, he
writes, suggests that the brain
actively attempts to cope with
pathology. To keep functioning
the brain relies on cognitive
networks already existing in the
specific functional domain of
the brain. Or otherwise it can
come up with compensatory
mechanisms, using other
networks.
Empty or full
Madagascar has a dry tropical
climate, with seasonal rains.
During these rainfalls, the
pachypodium rosulatum can
fill up its reservoir. What then
are the rainfalls that supply
the reserve in our brain?
Stern describes a few of the
researches through which
it has become clear that
experiences throughout a
Engaging in many leisure activities seems to slow down the onset of
Alzheimer symptoms
photo: David Rees/ Wikimedia Commons
lifetime play a role.
Studies of groups of
non-demented elderly have
shown that a higher level of
education and occupational
attainment contribute to the
build-up of cognitive reserve.
The 593 participants were
followed up for more than
four years. Having more than
eight years of education
turned out to lead to half the
risk of developing dementia
compared to those with a
shorter education. Similarly,
people working on a higher
occupational level had twice
lower risk of developing
dementia. These findings
implicated that educational
and occupational experiences
created a reserve.
During this research,
the effect of leisure activities
of elderly people was also
studied. Participants reported
the activities they engaged
in, such as knitting, going
for a walk or playing cards.
After grouping the elderly
people based on the amount
of activities they engaged
in, researchers found that
participants engaging in
more than six activities had
38% lower risk of developing
dementia.
Reviewing multiple
studies confirmed that
education, occupation, mental
activities and also IQ had a
protective effect. Yet, professor
Stern emphasises that the
evidence is still not definitive.
Protecting the blossom
In the end, cognitive reserve
can’t stop Alzheimer’s from
developing. It can only delay
the process until a certain
point. At that moment,
the reserve can no longer
compensate for the damage
and a patient will regress
faster. A patient with low
cognitive reserve goes through
a slower process of decline.
“This makes it hard to predict
how Alzheimer’s disease will
develop once a patient has
been diagnosed.” elaborates
Dr. Ossenkoppele.
Now how can we make
the flower blossom for as long
as possible? Ossenkoppele
points out that over the last
decennia, people have already
become more protected.
Relatively seen, less people
are suffering from dementia.
“One cause is better vascular
management: research has
“
Relatively seen, less
people are suffering
from dementia. One
explanation is that
education has become
more accessible.
”
provided medicine that
can fight the disease more
effectively.” Another might be
the fact that education is now
more accessible to people,
especially to women. This
would confirm that lifelong
learning should be encouraged
to delay dementia.
As mentioned earlier,
engaging in leisure activities
was also found to be related
to a higher cognitive reserve.
However, research has not
yet revealed which activities
are effective. Until now, only
physical activity was proved to
influence the development of
dementia.
Understanding the
changes that happen in
the brain’s behaviour as it
ages could help in finding
more targeted interventions.
Research in the VUMC
Alzheimer Centre compares
the brain damage shown
by functional MRI scans to
the cognitive skills people
show during extensive tests.
Examples of cognitive skills are
retrieving information from
memory and communicating
through language. By
comparing the control over
these skills to the damage in
the brain, the cognitive reserve
can be allocated to different
parts of the brain.
“In the future we would
want to give more specific
advice for cognitive and
physical activity based on the
person’s own current lifestyle.”
says Dr. Ossenkoppele.
Until that time when research
tells more, mental and physical
activities are encouraged in
general. A new hobby, a walk
in the park, solving a Sudoku.
The bottom line is to tickle our
brain regularly, in a variety of
ways.
Our brain won’t give away
its secrets easily. Hence
researchers will continue
their search. Only the proper
circumstances will cause the
flowers of our grey matter to
pop up and come into bloom.