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Sinonasal inflammation was associated with brain network changes that may precede cognitive symptoms in young people, according to a small proof-of-concept study.

Compared with healthy controls, people with chronic rhinosinusitis showed decreased functional connectivity within the frontoparietal network, a major functional hub central to modulating cognition, on resting-state functional MRI.

Additionally, these individuals had greater connectivity of this region to the default mode network (areas that are activated during introspective and self-referential processing) and decreased connectivity to the salience network (areas involved in detection and response to stimuli) on brain imaging, reported Aria Jafari, MD, of University of Washington in Seattle, and colleagues.

People with more severe rhinosinusitis inflammation tended to have greater differences in functional connectivity compared with controls, they stated in . Results were first reported at the 2020 American Rhinologic Society virtual meeting.

"Although definitive conclusions are not possible given the limitations inherent in the data set, including lack of rhinosinusitis-specific clinical information, our results present initial evidence for functional connectivity alterations as a potential basis for cognitive impairments seen in patients affected by chronic rhinosinusitis and may help direct future research," Jafari and colleagues said.

Yet the observed changes in functional connectivity were not accompanied by cognitive deficits in the study.

People with chronic rhinosinusitis and their matched controls shared similar cognitive status (on both the Mini-Mental State Exam and the Cognitive Function Composite tool) and reported similar sleep quality on the Pittsburgh Sleep Quality Index. There were no between-group differences in olfaction, taste, and pain, either.

"Therefore, given the brain's ability to adapt and compensate, particularly in young and cognitively healthy individuals, our findings may represent early and subclinical functional brain alterations that may precede or be more sensitive than anticipated behavioral responses," the investigators suggested.

"It is possible that a clinical chronic rhinosinusitis cohort with broader age distribution and more significant symptoms may have even greater changes in functional brain connectivity in the regions identified in this study," they added.

"Overall, I do think that this study gives credence to the large body of evidence that patients with chronic rhinosinusitis, or in this case sinonasal inflammation, do have issues with cognition," commented Nicholas Rowan, MD, of Johns Hopkins University School of Medicine in Baltimore, who was not part of the study.

It is well documented that sinonasal inflammation and chronic rhinosinusitis have substantial impact on quality of life, psychosocial function (e.g., depression), productivity, and general wellbeing, according to Rowan. Other research has found cognitive dysfunction to be responsive to or for chronic rhinosinusitis.

"Though unfortunately, the findings here are not actionable from a clinical standpoint, they do provide novel information for further prospective study of patients with chronic rhinosinusitis, as well as laboratory studies that are aimed to better understand the mechanism of why patients with CRS have such substantial quality of life implications," according to Rowan.

Comorbid psychiatric illness and sleep dysfunction are among the proposed mechanisms for cognitive dysfunction.

Jafari and colleagues said their data instead support a direct association of immune molecules, including cytokines and antibodies, with brain function.

The case-control study, using the , included 22 people with radiologic sinonasal inflammation who were matched 1:1 by age and sex to healthy controls. Sinonasal inflammation was classified as moderate in 13 people and severe in nine.

All were young adults age 22 to 35. Men accounted for 68% of the cohort.

Jafari's group acknowledged that the proof-of-concept study was retrospective and their sample small. Study results may have limited generalizability given that these were cognitively normal participants identified radiographically from a large database, the authors added.

"Future prospective studies are warranted to determine the applicability of these findings to a clinical chronic rhinosinusitis population," they said.

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