X-Message-Number: 29987
From: Mark Plus <>
Subject: New Scientist: 'Silent' abnormalities lurk within ageing brai...
Date: Thu, 1 Nov 2007 08:02:45 -0700



http://www.newscientist.com/article/dn12858-silent-abnormalities-lurk-within-ageing-brains.html

'Silent' abnormalities lurk within ageing brains
21:00 31 October 2007 
NewScientist.com news service 
Roxanne Khamsi 
 

One in eight people over 45 unknowingly has a brain abnormality such as weakened
blood vessels, dead tissue or a tumour. That is the conclusion of a study of 
2000 healthy participants, which found that a higher number than expected had an
undiscovered brain lesion.


The study by Aad van der Lugt at the Erasmus Medical Center in Rotterdam in the 
Netherlands and colleagues was designed to understand the risk factors for 
dementia in a population of seemingly healthy people aged 45 years and above. As
part of the research the scientists scanned the participants' brains using 
magnetic resonance imaging (MRI).


The results revealed an unexpectedly high number of abnormalities. In one case, 
scientists found a large benign tumour located inside the brain of an otherwise 
healthy individual. In another example, the team discovered brain haemorrhaging 
in a person who felt well, but had experienced minor head trauma a month before.


In total, van der Lugt and his colleagues found that 13% had some sort of brain 
lesion.

Ethical dilemma

This included 145 participants (7%) who had areas of the brain in which cells 
had died because of blood loss. The presence of such cell death, known to 
doctors as 'infarcts', has been linked to a doubled risk of dementia and a 
threefold risk of stroke, says van der Lugt. But he adds that there are no 
treatments for infarcts that decrease the chances of developing dementia or 
stroke.


The study also revealed that 1.8% of the participants had an undetected 
aneurysm, and 0.9 per cent had a type of benign tumour known as a meningioma.


"I'm surprised that the numbers they found were so high," says neuroethicist 
Paul Wolpe at the University of Pennsylvania in Philadelphia.


Van der Lugt says that his team notified only those subjects who had signs of a 
brain abnormality with a known risk and treatment, such as cancer and 
haemorrhage.


He notes that as brain scanning technologies improve, researchers will 
increasingly encounter unexpected signs of illness in study participants. "You 
have to be aware of the incidental findings and prepare for how you will deal 
with them," explains Van der Lugt.

'Waste of funds'

Experts say that MRI scans are thought to be safe, but caution that screening 
healthy people for brain abnormalities does not make sense at present. If the 
scans show a brain infarct, for example, there is nothing doctors can do to 
treat it.


Wolpe notes that MRI machines are extremely expensive and that using them to 
screen healthy people is a waste of medical funds. "Those are dollars that would
go to an underserved, uninsured population," he says.


Judy Illes at the University of British Columbia in Vancouver, Canada, says 
screening healthy people with MRI scans can create unnecessary anxiety. A 
leading expert on the ethical use of scanning technologies, Illes explains that 
small abnormalities such as infarcts can create needless worry. This worry, 
however, can itself pose a health risk.


Ultimately, though, she says the choice lies with the individual: "If people can
afford a medical test, and they fully understand the implications of taking the
test, they should not be prohibited from pursuing that desire."

Journal reference: New England Journal of Medicine (vol 357, p 1821)


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