Stroke study searches for link with dementia

by John Elder for The Age:

In a world-first study, Melbourne researchers are investigating why one in three stroke victims - even when they appear to make a good recovery - slides into dementia.It takes two or three years for symptoms to develop - and the reasons for this have never been explained.Lead researcher Amy Brodtmann said people had problems with thinking, speech and memory immediately after a stroke ''but they usually recover''.''What's happening down the track is some people, not everyone, are developing cognitive decline and some people are developing dementia,'' she said.The project involves studying the brains of 135 Melbourne people, who are being recruited within a day or two of suffering a stroke. Over three years, they will undergo four MRI scans - taken upon recruitment, at three months, one year and three years - to measure any changes in the brain, including shrinkage. The results are correlated with evidence of memory and cognitive impairment.Dr Brodtmann said understanding these changes could provide clues as to why stroke patients travel more rapidly into dementia than others.They may also show how to predict which patients will suffer cognitive impairment and can be assisted by early intervention.''We'll look at each subject and ask, why did they get worse and why did someone else get better?'' she said.''Was it some kind of medication or lifestyle or was it to do purely with age?''One aspect of brain degeneration being examined is ''white matter hyperintensities''- lesions in the white matter of the brain that have been strongly linked to a reduction in cognitive capacity.''One of the things we will be looking for in our study is whether these hyperintensities are more severe in patients with significant cognitive problems,'' said Dr Brodtmann.This could mean hyperintensities might either be causing the cognitive decline or they may be used as an early detection marker for dementia.People who present with pre-existing cognitive or memory loss - about a third of stroke victims - are precluded from the project.Fifty people have already been recruited, including a pilot group who began their scans two years ago. Dr Brodtmann said these people seemed to have undergone changes in the brain that are typical of patients with Alzheimer's disease without the dementia. However, claiming a causal relationship between strokes and dementia remains problematic, largely because the risk factors that predispose a person to having a stroke - smoking, late-onset diabetes, obesity, high cholesterol - can also cause cognitive problems.

The longitudinal study is being assisted by the Victorian Life Sciences Computation Initiative, funded by the Victorian government and hosted at the University of Melbourne.Source: http://bit.ly/110UIp1