Experts identify MRI biomarkers that could signal the early onset of Parkinson's
Using one of the most powerful MRI scanners to date, researchers believe they have identified subtle neural changes in the brain that precede Parkinson’s disease.
Led by researchers at the Champalimaud Foundation (CF), the new study deployed functional MR imaging techniques using a 9.4 Tesla scanner. This enabled them to visualize changes in the brain related to sensory impairments known to be related to PD. The added power of the scanner enables researchers to view anatomy in much greater detail than traditional equipment, providing new insight into the brain.
The experts focused their work on how certain sensory functions—smell and vision—manifest on imaging. Many PD patients report losing their sense of smell up to a decade prior to the onset of more serious symptoms; the same goes for visual disturbances. However, a dwindling sense of smell and deteriorating vision alone are not indicative of PD. But when they present together, it could be a warning sign of neurodegenerative alterations.
Now, Noam Shemesh, leader of the Preclinical MRI lab at CF, and Tiago Outeiro, a neuroscientist and Parkinson’s specialist at the University Medical Center Gottingen, are collaborating to study the utility these sensory impairments may have for foreshadowing early onset PD. The team has been conducting assessments using transgenic mice, which carry increased levels of the human protein alpha-synuclein.
Accumulation of this protein has been implicated in disease, as its spread can damage areas of the brain that control motor function. Mice carrying the protein also are believed to have an impaired sense of smell and visual disturbances.
For the study, researchers exposed the mice to different odors and visual stimuli while they underwent fMRI acquisitions. The team hoped to be able to spot changes in the brain when the mice were exposed to different smells and visual cues. This assessment also was done in a control group of mice that did not carry the alpha-synuclein protein, which proved to be beneficial.
Compared to the control group, the subjects with the alpha-synuclein protein displayed significantly lower activity along the olfactory and visual pathways in multiple cortical and subcortical sensory areas. This group also had much lower cerebral blood flow in these areas, “suggesting a strong neural driver for the dysfunction, along with more modest vascular contributions.”
“Assuming that the effects of alpha-synuclein in the mouse brain and in the human brain are similar, which I think is a reasonable assumption, one of the things we could now do would be to check fMRI signals in the brain of people who are reporting some anosmia, as well as their visual responses,” Shemesh explained. “And if we saw something weird in both sensory modalities, we could potentially say that there is something more global happening in their neural circuits, and that we need to follow up on that.”
Learn more about the findings here.
In addition to her background in journalism, Hannah also has patient-facing experience in clinical settings, having spent more than 12 years working as a registered rad tech. She began covering the medical imaging industry for Innovate Healthcare in 2021.