Signs of approaching Alzheimer’s disease may be visible about ten years before doctors recognize that the brain is diseased, suggests a recent study. Seniors who later developed dementia had MRIs ten years prior that revealed shrinkage in the brain’s cerebral cortex. This indicated the shrinkage was an early marker for Alzheimer’s. By measuring those areas of the brain in middle-aged people, researchers now believe this could strongly predict those who are more likely to develop the dementia of Alzheimer’s. This study, which included only symptom-free participants to begin with, tested the subjects’ cognitive abilities routinely for nine years.
All of the subjects, who were in their 70s when they entered the study, received brain MRI scans. Researchers then measured the areas of their brains known to be affected by Alzheimer’s. Within ten years of the scans, the seniors with the smallest measurements were found to be as much as three times more prone to succumb to obvious Alzheimer’s symptoms than those with larger measurements in those specific areas of the brains on the initial MRIs. Researchers have concluded that the areas of the brain most affected by Alzheimer’s show visible brain shrinkage in these regions ten years prior to becoming symptomatic for Alzheimer’s.
Because Alzheimer’s can only be diagnosed with 100% certainty during an autopsy, diagnosis of living subjects is made by clinical observation only. The fifteen study subjects who developed these apparent signs of Alzheimer’s dementia later during the study were all found to have a thinner layer of the cerebral cortex as measured by MRI, than did the subjects who did not show signs of dementia. The researchers therefore concluded that Alzheimer’s signs were visible ten years before doctors realized the patients were symptomatic.
The participants in this study were divided into three groups based on the size of their cerebral cortex measurements. Fifty-five percent of the subjects who were among those with the smallest measurements developed dementia associated with Alzheimer’s, while twenty percent among the group with medium-size cerebral cortex measurements and none of those in the group with the largest measurements developed dementia. This finding is a significant imaging marker of early brain alterations that predicts visible Alzheimer’s signs ten years before doctors would normally recognize the symptoms and diagnose the patient. The findings may even allow doctors to eventually predict how long it will be before a patient develops Alzheimer’s.