October 30, 2014
Science Daily/University Health Network (UHN)
A major cause of dementia has been potentially discovered, scientists report. In the type of dementia studied, there is damage to the white matter (nerve fibres) of the brain apparent on computerized tomography (CT) and magnetic resonance imaging (MRI) scans of older individuals.

Approximately 50 per cent of older individuals have evident white matter damage on their medical imaging scans. For most patients, these changes are harmless but when this damage is severe, it can cause impairment.

Previous studies have already established that the more white matter disease there is in the brain, the more likely patients are to have symptoms of dementia such as cognitive impairment or changes in behaviour. What was not understood is why this white matter disease develops -- the traditional assumption was that it might be the result of the natural aging process.

Krembil researchers hypothesized that the white matter disease (also called leukoaraiosis) may actually be the result of many tiny unnoticed strokes accumulating over time -- a finding that points to a potentially treatable form of dementia. The research was published today in the journal Annals of Neurology.

"We were surprised by the study findings" said Dr. Daniel Mandell, Neuroradiologist, Joint Department of Medical Imaging, Toronto Western Hospital and the principal investigator of the study. "The findings suggest that the tiny, silent strokes are likely much more common than physicians previously appreciated, and these strokes are likely a cause of the age-related white matter disease that can lead to dementia."
Science Daily/SOURCE :http://www.sciencedaily.com/releases/2014/10/141030100521.htm