Canadian scientists have made progress toward explaining how brain changes progress from mild cognitive impairment (MCI) to Alzheimer’s-type dementia.
Understanding this pathway is critical for development of therapies to address Alzheimer’s in its early stages.
In the new study, a team lead by Dr. Sylvie Belleville, Ph.D., Director of the Research Centre at Montreal Geriatric Institute and Professor of Psychology at Université de Montréal, showed the typical patterns of the brain’s progression to dementia.
Researchers compared changes that occurred over many years in people with stable MCI with changes in people for whom MCI progressed to a diagnosis of Alzheimer’s.
Belleville worked with doctoral student Simon Cloutier and a team of clinician researchers from Montreal. The study appears in the Journal of Alzheimer’s Disease.
Researchers found that different cognitive areas (language, inhibition, visuo-spatial processing, working memory, executive functions, etc.) do not change in a uniform way.
That is, cognitive decline does not occur in a linear fashion; instead, the path to dementia is complex and may sometimes be characterized by periods of stability followed by accelerated decline one or two years before diagnosis.
An accelerated decline in memory skills appears to be an indicator of future dementia.
“We’ve identified a profile of changes that characterizes people who progress towards dementia. In reality, a quick decline in episodic and working memory associated with language problems appears to be the typical profile of people who have a high risk of developing dementia within a short amount of time,” the researcher said.
Instead of seeing this as bad news, Belleville views these results as hope for seniors who are worried about their memories.
“Many people complain about their memories. However, the presence of a change is what determines the risk of progression.
“This study has let us characterize the parameters of decline in people who will eventually develop Alzheimer’s, which means we can better identify both benign symptoms and those that warrant particular attention. Rapid memory decline suggests that the onset of symptoms is probably due to a loss of the brain’s compensatory mechanisms.”
Alzheimer’s disease is diagnosed late in its progression and sometimes up to 15 years after its first effects on the brain. It is important to identify the early indicators so that patients can receive treatment as soon as possible.