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to make the brain better able to cope despite the pathological
changes of Alzheimer's disease.
For example, one study this year of 120 sedentary but healthy
olderadults without any memory problems assigned half the
participants to a 3-days-a-week programme
of physicalexercise3. After a year, researchers performed
magnetic resonance imaging (MRI) on several brainareas,including
the hippocampus, the brain structure responsible for memory
formation.
In older adults, the hippocampus typically shrinks by 12% each
year, and this is what happened in
the control
group. But in the exercise group, the volume of the hippocampus
actually increased by 2%. That's
probablymillions of cells, says research team member Kirk
Erickson, a psychologist at the University
ofPittsburgh,Pennsylvania. With one year of exercise, we are in
essence rolling back the clock by one to two
years.
Brain trainingAnother report4, also published this year,
suggests that similar mechanisms are at work whenpeople
exercisetheir brains. Canadian researchers used functional MRI to
analyse brain activity in 15 people withMCI. After aone-week
programme designed to teach the participants new memory strategies,
there wasactivation in several
additional brain regions during memory tests, suggesting that
intact areas of the brain were able totake overfrom damaged areas.
The participants also scored better on the tests.Many studies of
cognitive stimulation and dementia make use of computer games
designed to boostmentalskills. Although such 'brain training'
interventions do not generally make healthy people smarter,
theyproducepositive results in people with Alzheimer's disease and
related conditions. One 2006 trial funded bythe USNational
Institutes of Health showed that brain training can counteract some
of the cognitive declineexpectedwith ageing5. In that study known
as Advanced Cognitive Training for Independent and VitalElderly
(ACTIVE)
people over 65 years of age who did a five- to six-week brain
training programme focusing onmemory,reasoning or speed of
processing skills were better at these skills than control
participants even fiveyears later.Computerized brain training
programs are popular among researchers because these
interventionsarecontrollable and predictable, especially compared
with intellectual pursuits in the real world. But thisdoesn't
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mean that people need to play computer games to stay mentally
agile, says Sachdev. Instead, heargues,people are likely to benefit
from any intellectual pursuit that both requires effort (something
whereyou challengeyour brain) and is enjoyable (so that you can
sustain it). That could mean anything from taking upthe
clarinet
to doing Sudoku puzzles.Food for thoughtMeanwhile, other
lifestyle factors that can modify the risk of Alzheimer's disease
are continuing toemergethrough epidemiological research. These
types of studies, involving observation of thousands ofpeople and
theirhabits, underpin our knowledge about the Mediterranean diet,
which includes a relatively highconsumption offruits, vegetables,
whole grains and olive oil, relatively low consumption of red meat
and saturatedfat, and aglass of red wine with dinner.Eating these
foods has already been shown to reduce the risk of cardiovascular
disease,hypertension and
diabetes. In the past few years, three independent
epidemiological studies conducted in New York6,Chicago7and
Bordeaux, France8, have shown that those who eat mostly Greek
peasant food also stay thesharpestmentally. There has been
converging evidence that adherence to such a diet is related to
lower riskof cognitivedecline or Alzheimer's disease, says Nikolaos
Scarmeas, a neurologist at Columbia University inNew York.
A team of Columbia University researchers including Scarmeas
asked 1,880 New Yorkers detailedquestionsabout their eating habits,
then studied them for an average of five-and-a-half years. They
found thatthe people
with the most Mediterranean diet have up to a 40% lower risk of
developing Alzheimer's diseasethan those whoeat less Mediterranean
food6. Results like these are so promising that several groups
around theworld areplanning randomized trials of the Mediterranean
diet as a way of preventing Alzheimer's disease.Evidence that
social engagement helps to prevent dementia also comes primarily
from observationalstudies.For example, among more than 6,000 people
aged 65 or older in Chicago, those with the mostextensive
socialnetworks and the highest levels of social engagement have the
lowest rates of cognitive decline9.It can be difficult to measure
people's level of social engagement and it is even harder to
designrandomizedtrials to investigate it. Disentangling the effects
of social engagement from those of other lifestyleelements is
farfrom straightforward. Still, social engagement is a form of
intellectual engagement, argues LindaTeri, professorof psychosocial
and community health at the University of Washington in Seattle.
Teri has designedprogrammes to encourage physical activity and
social connections in people with MCI and dementia.When weare with
other people, we are listening to the conversation, we're tracking
ideas, we're forming ourown ideas,she says. We're actually engaging
in quite a bit of cognitive skills.
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Claude Messier said:So people who exercise in groups may benefit
from both the social stimulation and the physicalactivity.
Forexample, consider Erickson and colleagues' research into
exercise and brain changes in healthyolder people3.Instead of
aerobic exercise, the control group met three times a week to do
stretches. This did not
increase thesize of their hippocampus, but it did improve their
scores on a simple computerized test of memory,similar tothe
improvements in the exercise group. Erickson suggests that this
social stimulation benefits otherparts ofthe brain that the study
did not measure.
Alzheimer Association (2013). Brain Tour. Retrieved on March 9,
2013. From
http://www.alz.org/braintour/early_stage.asp
Battistin, L., & Cagnin, A. (2010). Vascular cognitive
disorder. A biological and clinical overview".
Neurochem. Res.35(12), 19338.doi:10.1007/s11064-010-0346-5
Berchtold, N. C., & Cotman, C. W. (1998). Evolution in the
conceptualization of dementia and Alzheimers
disease: Greco-Roman period to the 1960s. Neurobiology of aging,
19(3), 173-189.
Boller, F., & Forbes, M. M. (1998). History of dementia and
dementia in history: an overview. Journal of
the neurological sciences, 158(2), 125-133.
Braak, H. , & Braak, E. ( 1991). Neuropathological staging
of Alzheimer - related changes.Acta
Neuropathologica , 82 , 239259 .
Brodaty, H., McGilchrist, C., Harris, L., & Peters, K. E.
(1993). Time until institutionalizationand death in patients with
dementia: role of caregiver training and risk factors.Archives
of
Neurology, 50(6), 643.
Cummings , J. L. , & Mega , M. S. (2003).Neuropsychiatry and
behavioral neuroscience . New
York : Oxford University Press.
Erickson, K. I., Voss, M. W., Prakash, R. S., Basak, C., Szabo,
A., Chaddock, L., ... & Kramer, A. F.
(2011). Exercise training increases size of hippocampus and
improves memory. Proceedings of the
National Academy of Sciences, 108(7), 3017-3022.
Esquirol J. Des maladies mentales. Paris: Baillie`re, 1838
Green, R. C. ( 2005).Diagnosis and management of Alzheimer s
disease and other dementias
( 2nd edn.). Caddo, OK: Professional Communications.
Jellinger, K. A. (2006). Alzheimer 100highlights in the history
of Alzheimer research. Journal of neuraltransmission, 113(11),
1603-1623.
Middleton, L. E., & Yaffe, K. (2009). Promising strategies
for the prevention of dementia. Archives of
Neurology, 66(10), 1210.
Slooter, A.J.C., Tang, M.X., Van Duijn, C.M., et al. (1997)
Apolipoprotein E episilon 4 and the risk of dementia with
stroke: A population-based investigation.JAMA, 277, 818-821
http://www.alz.org/braintour/early_stage.asphttp://www.alz.org/braintour/early_stage.asphttp://en.wikipedia.org/wiki/Digital_object_identifierhttp://en.wikipedia.org/wiki/Digital_object_identifierhttp://dx.doi.org/10.1007%2Fs11064-010-0346-5http://dx.doi.org/10.1007%2Fs11064-010-0346-5http://dx.doi.org/10.1007%2Fs11064-010-0346-5http://dx.doi.org/10.1007%2Fs11064-010-0346-5http://en.wikipedia.org/wiki/Digital_object_identifierhttp://www.alz.org/braintour/early_stage.asp
