November 2, 2004 — Doctors have found important
new evidence to explain why mental function becomes less efficient with
ageing. In the first study of its type in the world, a team at the
University of Edinburgh found that worse mental function is linked with
abnormally enlarged channels around blood vessels in the brain. The
report, published in the Journal of Neurology, Neurosurgery and
Psychiatry, will help doctors to better understand the causes of
Dementia and milder forms of loss of mental ability affects millions
of older people every year, but the causes are unclear. Previous
research using brain scanning has shown that brain shrinkage and
changes in the brain’s white matter ‘wiring’, are associated with
mental function slowing down in old age. This research adds a new way
in which damage to the brain may result in dementia and other mental
loss in older people.
The abnormal channels are known as enlarged perivascular spaces.
Rare in young, healthy adults, they are very commonly seen in the brain
scans of older people, and in conditions such as diabetes, Parkinson’s
disease, and high blood pressure. Researchers have long noted these
abnormalities, but until now there has been no research on any links
with mental function in old age. The enlarged perivascular spaces might
be an indicator of overall brain shrinkage, or they might reflect
specific damage to brain tissue around blood vessels.
Dr. Alasdair MacLullich, of the University’s Geriatric Medicine
Unit, measured mental ability in100 healthy elderly male volunteers
from the Edinburgh area. Professor Joanna Wardlaw, from the Brain
Imaging Research Centre for Scotland, measured the extent of the
enlarged perivascular spaces in these men using a new and innovative
method of analysis. The team, which also included researchers from
psychology and endocrinology, found that men with more enlarged
perivascular spaces had worse mental ability.
Dr. MacLullich commented: "These findings mean that we should
certainly be looking more closely at enlarged perivascular spaces as a
cause of dementia and other mental decline in old age. They raise the
interesting possibilities that there may be substances in the blood,
such as cholesterol or sugar levels, or even blood pressure itself,
that may contribute to memory decline as people become older. This puts
a spotlight on blood vessels, so we are now working to find out how
these changes around the brain’s blood vessel supply arise."
Source : University Of Edinburgh