Chronic sinus inflammation linked to altered brain activity
More than one in 10 adults in the United States suffer from chronic rhinosinusitis, a persistent inflammatory sinus condition. A new brain imaging study is suggesting chronic rhinosinusitis is associated with functional brain connectivity changes that could explain a number of cognitive problems often linked to the disease.
“We know from previous studies that patients who have sinusitis often decide to seek medical care not because they have a runny nose and sinus pressure, but because the disease is affecting how they interact with the world: They can't be productive, thinking is difficult, sleep is lousy,” explains lead author on the new study, Aria Jafari. “It broadly impacts their quality of life.”
To investigate this problem Jafari and a team of researchers looked at data from the Human Connectome Project, an ongoing open-source project mapping neural data from over a thousand subjects. The new study homed in on 22 subjects with moderate or severe chronic sinusitis, matched against 22 healthy subjects.
The researchers focused on functional connectivity between different brain regions and the results were compelling. Those subjects with chronic sinus inflammation displayed decreased functional connectivity in the frontoparietal network and the salience network.
The frontoparietal network (FPN) in particular plays a central role in high-order neural processing and prior studies have suggested FPN activity can be used to predict cognitive performance and regulate attention.
Interestingly, the decreased functional connectivity in the salience network was seen to be linked to increased activity in several nodes of the default mode network. This particular pattern seen in the subjects with sinus inflammation is hypothesized to be linked to a reduction in the ability to focus and concentrate.
Kristina Simonyan, a co-author on the new study, notes the 22 chronic rhinosinusitis patients did not display any clinically significant signs of cognitive impairment. However, the cohort studied were young (aged between 22 and 35) and longitudinal studies may be needed to understand whether these brain connectivity alterations lead to noticeable cognitive decline over decades.
“The participants with moderate and severe sinus inflammation were young individuals who did not show clinically significant signs of cognitive impairment,” says Simonyan. “However, their brain scans told us a different story: The subjective feelings of attention decline, difficulties to focus or sleep disturbances that a person with sinus inflammation experiences might be associated with subtle changes in how brain regions controlling these functions communicate with one another.”
Exactly how chronic sinus inflammation could be causally linked to these functional brain connectivity alterations is unclear at this stage but the researchers suggest at the very least this new study indicates a neurophysiological reason for the oft-reported cognitive symptoms seen with the disease.
Moving forward, Jafari suggests more focused research on patients with sinus inflammation will help highlight the relationship between localized sinus inflammation and cognition. The researchers are also keen to investigate how acute treatment of sinus inflammation can influence functional brain connectivity in these targeted regions.
“The next step would be to study people who have been clinically diagnosed with chronic sinusitis,” says Jafari. “It might involve scanning patients’ brains, then providing typical treatment for sinus disease with medication or surgery, and then scanning again afterward to see if their brain activity had changed. Or we could look for inflammatory molecules or markers in patients’ bloodstreams.”
The new study was published in the journal JAMA Otolaryngology-Head & Neck Surgery.
Source: UW Medicine