Researchers at the Baycrest Rotman Research Institute (RRI) and the University of Toronto said their study indicates that there are observable changes in the brain’s structure which could predict the onset of dementia even before patients show noticeable signs of the disease such as memory loss.
The team, which studied 40 adults between the ages of 59 and 81, found evidence of less brain tissue the anterolateral entorhinal cortex located in the brain’s temporal lobe. This is the sub-region of the brain where Alzheimer’s disease originates from.
Early detection of alterations of the brain structure has the potential of identifying seemingly but at-risk individuals and can also foster the development of drugs and therapeutic interventions.
The Alzheimer Society of Canada reports that there are more than 560,000 Canadians living with dementia. More than 1.1 Canadians are affected by the disease.
As many as 25,000 new cases of dementia are diagnosed each year in Canada. The total cost of caring for people with dementia in the country is estimated at $10.4 billion.
The joint study, published in the Neurobiology of Aging journal on May 8, looked at older adults who are living in the Toronto community without assistance and who were unaware of any major memory problems, but who scored below the normal benchmark on a dementia screening test.
It is also the first study to demonstrate that performance on the Montreal Cognitive Assessment (MoCA) dementia screening test is linked to the volume (size) of this sub-region, along with other brain regions affected early in the course of Alzheimer’s disease.
“This work is an important first step in determining a procedure to identify older adults living independently at home without memory complaints who are at risk for dementia,” says Morgan Barense, associate professor in the department of psychology in the Faculty of Arts & Science at U of T and senior author on the study.
Scientists were able to reliably measure the volume of the anterolateral entorhinal cortex by using high-resolution brain scans that were collected for each participant.
The strongest volume differences were found in the exact regions of the brain in which Alzheimer’s disease originates. The researchers are planning a follow-up study to determine whether people who demonstrated poor thinking and memory abilities and smaller brain volumes indeed go on to develop dementia.
“The early detection of these at-risk individuals has the potential to facilitate drug developments or other therapeutic interventions for Alzheimer’s disease,” said Rosanna Olsen, first author on the study, RRI scientist and assistant professor in U of T’s department of psychology.
“This research also adds to our basic understanding of aging and the early mechanisms of Alzheimer’s disease,” she said.