MRI study pinpoints neural roots of lingering fatigue post-COVID infection
Structural and functional connectivity in several areas of the brain are diminished in patients who struggle with symptoms of long COVID, especially among those suffering from extreme fatigue.
These changes are most prevalent in the frontal areas, but the variations differ based on the type of fatigue—physical or mental—people experience, according to a new paper published in Psychiatry Research.
“Among symptoms of post-COVID syndrome (PCS), fatigue is one of the most frequent and most disabling, along with cognition, and is usually persistent,” corresponding author Jordi A. Matias-Guiu, with the San Carlos Health Research Institute in Madrid, Spain, and co-authors noted. “Fatigue symptomatology may affect between 35% and 60% of patients after infection, and both physical and cognitive fatigue have been described in PCS patients. These fatigue symptoms adversely affect patients' working status and quality of life.”
For the study, researchers analyzed MRI scans of 129 individuals with COVID side effects that lingered for a year or more after they had recovered from their initial infection. In addition to undergoing imaging, participants also completed assessments that gauged their level of fatigue, neuropsychological and subjective cognitive complaints.
The majority (86%) of patients reported having serious issues with fatigue. Among these individuals, experts observed changes in structural and functional connectivity in the frontal, temporal and cerebellar areas of the brain.
Mental fatigue was found to have stronger associations with variations in functional connectivity in the left prefrontal areas, anterior cingulate, left insula, and temporal, occipital and cerebellum regions. Physical fatigue was more often observed alongside increased connectivity between the cerebellum and bilateral temporal areas.
“Interestingly, left prefrontal, anterior cingulate and the left insula are central hubs of the so-called ‘fatigue network’ related to mental fatigue,” the group explained. “These results revealed that mental fatigue in PCS patients is also related to poorer functional connectivity between these brain areas and other areas of the brain such as cerebellar and temporal areas.”
Some of the findings observed have also been reported in patients who have multiple sclerosis, “which could suggest partially shared pathophysiological substrates of fatigue symptoms,” the group indicated.
In looking at the number of reinfections, subjective complaints and MRI findings, the group suggested the multiple infections could increase the risk of alterations in functional connectivity observed in patients who reported struggling more with mental fatigue.
The group suggested that their findings could potentially serve as biomarkers for more objective analyses of patients with PCS in future clinical trials.
Learn more about the research 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.