New research finds subtle brain changes in pre-symptomatic Alzheimer's patients

A new peer-reviewed study from the Medical University of South Carolina (MUSC) report in Brain Connectivity has found individualized brain “fingerprints” which can help diagnose early Alzheimer's Disease (AD) in pre-symptomatic patients.

Using an innovative brain imaging technique, the neuroscientists conducting the research could visualize subtle brain changes in pre-symptomatic Alzheimer's patients, which could help determine how the disease begins and progresses.

“Prior studies have not found an association between brain function and behavior in preclinical AD,” said Andreana Benitez, Ph.D., one of the study researchers, in a press release. “Using these individualized maps of brain function, we found a potential brain-based reason for very subtle cognitive changes in this early phase of the disease.”

The team used a new technique called “the individualized functional connectome” which was developed by their collaborator, Hesheng Liu, Ph.D, to analyze the brain images.

This highly sensitive technique is able to show unique brain patterns for each individual, something that traditional methods cannot do.

“We all have the same functional parts of our brain, but they're positioned slightly differently, sort of like a fingerprint,” said Stephanie Fountain-Zaragoza, Ph.D, another one of the study researchers, in a press release. “This method creates an individualized brain fingerprint that more accurately reflects where the different functional regions are in each individual’s brain.”

The team of neuroscientists applied this method to a group of 149 research participants, ages 45 to 85, who did not have signs of cognitive decline.

Each of the participants' brains were scanned by a positron emission tomography (PET) scan and divided into groups based on the results—those who showed PET scan evidence of early amyloid-beta protein buildup, and those who did not.

In order for the researchers to have the brain “fingerprints” generated, they also underwent MRI scans.

Using behaviour-based testing, researchers assessed how well the research participants performed cognitively.

What they found was certain changes in the brain fingerprint were associated with those with worse information processing abilities in the participants who had amyloid-beta buildup, or preclinical Alzheimer's.

Conversely, they found information processing was better in those with higher within-network connectivity, or more brain activity within important areas of the brain.

“A healthy brain typically has a balance of connectivity within and between its networks,” said Fountain-Zaragoza. “We found that in preclinical AD—when amyloid build-up is present in the brain—this balance can be disrupted, potentially leading to information no longer being processed as efficiently.”

The study suggests early states of protein buildup in the brain could affect cognitive abilities before the symptoms of cognitive decline become noticeable. Plus, it suggests that changes in connectivity within certain brain networks could signal early issues with information processing abilities, which, according to the researchers, could be an area therapies could target to improve the outcomes for those with Alzheimer's.

This method could improve how preclinical cases of Alzheimer's are studied, particularly as adults with preclinical Alzheimer's don’t have noticeable symptoms of cognitive decline—despite having the earliest signs of disease such as buildup of amyloid-beta proteins in their brain, according to the study.

In the future, the researchers plan to explore how brain changes affect the progression of Alzheimer's as well as potential treatments, as they expand this research.

“There's a lot of great work aimed at helping us understand the earliest signs and symptoms of Alzheimer’s disease,” said Fountain-Zaragoza. “This area of work is important for understanding the full spectrum of the disease and identifying who might be at risk of developing it.”