Scientists have discovered a potential brain imaging predictor for dementia, which illustrates that changes to the brain’s structure may occur years prior to a diagnosis, even before individuals notice their own memory problems.
The study, published in the Neurobiology of Aging, looked at older adults who are living without assistance and who were unaware of any major memory problems, but scored below the normal benchmark on a dementia screening test.
Within these older adults, researchers also found evidence of less brain tissue in the same subregion of the brain where Alzheimer's disease originates (the anterolateral entorhinal cortex located in the brain's temporal lobe).
This is the first to measure this particular brain subregion in older adults who do not have a dementia diagnosis or memory problems that affect their day-to-day routine. 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 subregion, along with other brain regions affected early in the course of Alzheimer's disease.
The team studied 40 adults between the ages of 59 and 81 who live independently (or with a spouse) at home. All participants were tested on the MoCA. Those scoring below 26 — a score that indicates a potential problem in memory and thinking skills and suggests further dementia screening is needed — were compared to those scoring 26 and above.
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 the individuals who demonstrated poor thinking and memory abilities and smaller brain volumes indeed go on to develop dementia.
Paper: “Anterolateral entorhinal cortex volume predicted by altered intra-item configural processing”
Reprinted from materials provided by Baycrest Centre for Geriatric Care.