Dementia subtype can be predicted five years before onset

TORONTO, Ontario (November 13, 2012) - Researchers have found a way to predict whether a person will develop Alzheimer's Disease or vascular dementia up to five years before diagnosis, according to a new study.

"Knowing whether someone is at risk of developing vascular dementia is important, because we can treat this condition and possibly prevent the onset of dementia," says Dr. Mary Tierney, Director of the Primary Care Research Unit at Sunnybrook Health Sciences Centre and senior author of the study. "The preventative stroke treatments we use, such as baby Aspirin, do have risks, so these findings will help clinicians determine which patients will benefit most from these treatments," she adds.

Published in the November 2012 issue of the journal Alzheimer's & Dementia and using data from the Canadian Study of Health and Aging, researchers examined the accuracy of two neuropsychological tests that measure learning ability and verbal fluency along with the Hachinski Ischemic Score, which measures the extent of vascular disease.  

From these results, researchers were able to accurately predict which groups the 504 participants would fall into after five years: those who developed Alzheimer's disease, those who developed vascular dementia, and those who would remain stable or progress to other diagnoses. After five years, 65 people were diagnosed with Alzheimer's, and 22 with vascular dementia.

Those who developed Alzheimer's showed more difficulty learning new information, but had better verbal fluency, or the ability to rapidly access words from one's vocabulary, than those who developed vascular dementia. Those who developed vascular dementia had completely opposite results- they could learn new information, but had difficulty with verbal fluency. 

"Until now, the general consensus among dementia researchers was that the earliest stages of Alzheimer's disease and vascular dementia followed a similar course, and had similar effects on memory and other cognitive abilities," says lead author Paul Brewster, a doctoral student in neuropsychology at the University of Victoria. "In our study sample, which was one of the largest longitudinal studies to include neuropsychological testing, this was not the case."

Alzheimer's and vascular dementia are the two most common forms of dementia. Close to half a million people in Canada currently live with some form of dementia, and that number is expected to grow to 750,000 within 20 years due to the aging population.

While medications are available to treat symptoms of dementia, and measures can be taken to prevent or delay onset of the disease, there is currently no cure.

"For the best chance at avoiding degenerative brain disease, try to engage in a healthy lifestyle, such as being more mentally, physically and socially active, keeping weight down, stop smoking   and eating better," says Dr. Tierney, who is Professor and Clinician Scientist in the Department of Family & Community Medicine, University of Toronto. After all, she points out, "there is no downside to doing these things."

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Media contact:
Nadia Norcia Radovini
Communications Advisor
Sunnybrook Health Sciences Centre
416.480.4040