Researchers at Western University are looking at both brain metabolism and brain structure to pinpoint early signs of Alzheimer’s disease. By looking specifically at an area of the brain responsible for remembering past personal experiences, which is one of the first and most severe losses in Alzheimer’s disease, they were able to show specific changes even during the earliest phases of memory loss in patients.
The hope is that this new research will lay the foundation for definitive early biomarkers of Alzheimer’s disease.
“The really exciting implication here is that this may be used as an early indicator of problems in the brain that may lead to Alzheimer’s disease,” said Robert Bartha, PhD, Professor at Western’s Schulich School of Medicine & Dentistry and Scientist at Robarts Research Institute.
Early detection has become increasingly important in the search for treatments for the disease because once a patient begins to show symptoms, the changes in the brain are irreversible. And while there are currently no solid treatments, diagnosing early increases the likelihood that treatments of the future will be able to halt the disease before there are major cognitive changes or memory loss.
Using ultra-high magnetic field 7T MRI brain imaging as well as cognitive and memory testing, the research team looked at three groups of patients – those with a diagnosis of Alzheimer’s disease, those with mild cognitive impairment, and a control group of older adults.
The research team found reduced levels of two metabolites (glutamate and N-acetyl aspartate) in both patients with Alzheimer’s disease, and patients with mild cognitive impairment, who experience a less severe form of memory loss that often comes before Alzheimer’s disease. N-acetyl aspartate levels generally indicate overall neuronal health, while glutamate is used primarily for neuronal communication. They also found that both of these groups of patients had changes in the white matter structure connecting the hippocampus to other brain regions.
“This is one of the first times that there has been a direct link made between metabolic changes in specific regions and microstructural damage in the brain,” said Bartha. “So from that perspective, it does give us new insight into what things are changing at the same time in different parts of the brain.”
First author of the paper, MD/PhD candidate Dickson Wong says the results suggest that the brain metabolite changes may actually come before the structural changes. “This finding is an important one because one goal of the field is to identify a clear chain of events that led to the clinical presentation of Alzheimer’s disease,” Wong said. “Based on our findings, a physician may perhaps gain more insight into the early stages of the disease if they chose to measure metabolic changes rather than structural ones.”
The study was published online in the Journal of Alzheimer’s Disease and was supported by Western’s BrainsCAN and the Alzheimer Foundation of London and Middlesex.