A new study using highly sensitive MRIs found that dopamine levels may provide doctors with more clues to diagnose Alzheimer’s disease earlier than is currently possible.
In the recent study published in the Journal of Alzheimer’s Disease, researchers looked at a dopamine-rich area of the brain called the ventral tegmental area (VTA) and how it’s linked to other parts of the brain.
They wanted to see if they could piece together the puzzle of how to diagnose Alzheimer’s disease earlier, by examining the VTA and its interactions with other areas of the brain.
The study was led by Annalena Venneri, PhD, professor of clinical neuropsychology in the Department of Neuroscience at the University of Sheffield, England.
They analyzed 110 adults using 3Tesla MRI technology and memory testing. This type of MRI is twice the strength of a traditional MRI, allowing for more precise and higher quality measurements.
By using these MRI readings, the researchers calculated the ratios comparing the size of the hippocampus with other portions of the brain in relationship to memory performance.
The results showed that there was a link between the size and functionality of the dopamine-rich VTA, the size of the hippocampus, and the ability to learn new information.
The smaller size of the VTA meant a smaller amount of dopamine going to the hippocampus which resulted in decreased memory performance.
The dopamine found in the VTA is a chemical that plays a role in reward-motivated behavior, and helps to control movement and form new memories.
Scientists have found that loss of dopamine may be part of the reason why people with Alzheimer’s disease have less effective memories.
When dopamine is sent from the VTA to the hippocampus, it allows the hippocampus to function. However, if the hippocampus — which is responsible in part for forming new memories — doesn’t receive enough dopamine, the ability to learn new information suffers. This in turn increases the risk of dementia.
Although scientists already saw these results in animal models, this is the first time this link was seen in humans.
A growing problem
According to the Centers for Disease Control and Prevention (CDC), Alzheimer’s disease is the most common form of dementia.
Of the estimated 5.7 million Americans living with Alzheimer’s, approximately 200,000 of them are under the age of 65, according to the Alzheimer’s Association.
This problem is growing, too. By the year 2050, the number of people with Alzheimer’s is projected to rise to 14 million.
As a result, researchers have been searching for ways not only to treat Alzheimer’s disease, but to better understand why and how people develop it.
The results of this latest study could be promising in helping researchers develop better targeted treatments. Currently there’s no cure or treatment to delay the disease.
"Another possible benefit is that it might lead to a different treatment option with the potential to change or halt the course of the disease very early on, before major symptoms manifest" Venneri said in a statement.
A jumping off point
Dr. Mariel Deutsch, attending behavioral neurologist at Northwell Health Neuroscience Institute in Great Neck, NY agrees that this is a good start for future research — but patients shouldn’t be waiting on pins and needles for the screening.
"It would be too soon to incorporate these findings into the clinical care of patients, but it opens up new areas for research trials," she said.
Venneri acknowledged that more research is needed to confirm these early findings, but said that this study can be a jumping off point.
"More studies are necessary, but these findings could potentially lead to a new wave [of] screening the elderly population for early signs of Alzheimer’s disease, changing the way brain scans are acquired and interpreted and using different memory tests," said Venneri.
Deutsch also said that the results need to be replicated before the MRI scans can be considered a true signature of Alzheimer’s disease pathology.
Should these results hold in future tests, it could open up a new way of treating the disease.
This "suggests another important mechanism in the development of Alzheimer’s disease, which could be a target for early treatment," Deutsch said. "This study proposes another biomarker of the disease, which may allow patients to be diagnosed more accurately and earlier."
Rajiv Bahl, MD, MBA, MS is an emergency medicine physician and health writer. You can find him at www.RajivBahlMD.com.