Low dopamine levels may indicate Alzheimer's disease.
Dopamine is a neurotransmitter that is involved in regulating emotional responses and movement.
The new study shows that the loss of cells that use dopamine could impair function in brain regions that create new memories.
The results of the study were recently published in the Journal of Alzheimer's Disease.
Its authors believe that this finding has the potential to transform the way in which Alzheimer's is diagnosed.
Their recent findings may also pave the way to much-needed new treatments for the debilitating condition.
Alzheimer's is rising in prevalence
Alzheimer's disease is the most common dementia type, accounting for 60–80 percent of all cases. People who have Alzheimer's tend to experience memory loss and other cognitive problems that interfere with their day-to-day lives.
Around 5.7 million people in the United States have Alzheimer's, but numbers are projected to rise nearly 14 million by 2050. Alzheimer's is also the sixth leading cause of death in the U.S.
Medical News Today have recently covered another study published in the Journal of Alzheimer's Disease, which suggested that one daily dose of ibuprofen could contribute to preventing Alzheimer's by reducing inflammation.
The authors of that study had previously discovered that a peptide called amyloid-beta 42 (Abeta 42) is present in increased levels in the saliva and brains of people with Alzheimer's.
The scientists propose that a simple saliva test could help to predict a person's risk of Alzheimer's, years before any symptoms become visible.
As Abeta 42 triggers inflammation, they reason that a daily dose of ibuprofen or other nonsteroidal anti-inflammatory drugs may be effective at keeping this inflammation at bay among people who test positively for high levels of this peptide.
Low dopamine and hippocampal function
The researchers used a type of MRI scan called 3Tesla, which is twice the strength of standard MRI, to scan the brains of 51 healthy adults, 30 with mild cognitive impairment, and 29 with Alzheimer's disease.
Analyzing the results, they found a link between the size of two key brain areas — the ventral tegmental and hippocampus — and the ability of the participants to learn new information.
Lead study author Annalena Venneri — of the Sheffield Institute for Translational Neuroscience at the University of Sheffield in the United Kingdom — explains the results.
"Our findings suggest that if a small area of brain cells, called the ventral tegmental area, does not produce the right amount of dopamine for the hippocampus, a small organ located within the brain's temporal lobe, it will not work efficiently."
"The hippocampus," she adds, "is associated with forming new memories, therefore these findings are crucial to the early detection of Alzheimer's disease. The results point at a change which happens very early on, which might trigger Alzheimer's disease."
"This is the first study to demonstrate such a link in humans."
A new way to diagnose Alzheimer's?
Venneri and colleagues believe that a new diagnosis method, involving memory tests and scans of the ventral tegmental and hippocampus, could "revolutionize" screening for the early signs of Alzheimer's.
Another possible benefit of this research, as outlined by Venneri, is that the findings could point the way toward a new type of Alzheimer's treatment — hopefully, one with the potential to interrupt the course of the disease at a very early stage.
Next, the team will investigate how early on changes can be seen in the ventral tegmental area, and whether or not any existing treatments are effective against these changes.