A new case-control study has suggested that patients with chronic rhinosinusitis may have alterations in functional brain connectivity, which could lead to cognitive dysfunction.
The study was led by Aria Jafari, MD, Department of Otolaryngology–Head and Neck Surgery, University of Washington, Seattle. The team used open-access data to compare individuals with sinonasal inflammation with age-matched and sex-matched controls.
“Several contemporary studies of chronic inflammatory and immune conditions, including Sjögren syndrome and inflammatory bowel disease, have identified alterations in functional connectivity within networks associated with cognitive control and stimulus detection,” the investigators wrote.
However, they noted, there remains a need to further understand and clarify cognitive dysfunction seen in chronic rhinosinusitis.
Assessing Functional Connectivity
In order to examine the functional connectivity of affected patients, the investigators utilized resting-state functional magnetic resonance imaging (fMRI) data extracted from the Human Connectome Project.
They evaluated data of 22 patients with chronic rhinosinusitis. Patients with a history of psychiatric disorders, neurological diseases, and genetic diseases were excluded. The team also excluded those with a history of diabetes or cardiovascular diseases.
Among both investigative and control controls, 2 were aged 22-25 years old, 26 were 26-30 years, and 16 were aged 31-35 years. A majority (68%) were men.
As for those in the inflammation group, 13 were categorized with moderate inflammation (Lund-Mackey score [LMS] < 14) and 9 were categorized with severe inflammation (LMS ≥ 14)
“The primary outcome was the difference in resting state functional connectivity within and between the default mode, frontoparietal, salience, and dorsal attention brain networks,” they wrote. “Secondary outcomes included assessments of cognitive function using the National Institutes of Health Toolbox Cognition Battery.”
The investigators reported that those with sinonasal inflammation presented with decreased functional connectivity within the frontoparietal lobe. More specifically, this was observed in a region that involved bilateral frontal medial cortices.
They further noted that the region showed increased functional connectivity to 2 nodes within the default-mode network and decreased functional connectivity to 1 node within the salience network.
The level of inflammation severity was associated with a greater magnitude in this discrepancy of functional connectivity.
Despite these findings, the team observed no differences in cognitive assessment between the groups.
“Similarly, analysis did not indicate any differences in olfaction, taste, and pain between groups as measured by the NIH Toolbox Sensation Measures testing component,” they wrote.
And finally, there were no differences in sleep quality and its subdomains—latency, duration, habitual efficiency, disturbances, use of sleep medications, and daytime dysfunction, etc.—which were assessed using the Pittsburgh Sleep Quality Index (PSQI).
“In this proof-of-concept study, we found that compared with controls, participants with sinonasal inflammation demonstrated decreased functional connectivity within the frontoparietal network, a major network that has a central role in modulating cognition through extensive connections to other brain areas,” the team wrote.
On the other hand, there were increased connections between a functional hub that modulates cognition and areas activated during introspective and self-referential processing.
Although their data was limited by significant gaps, such as lack of rhinosinusitis-specific clinical information, the investigators indicated the significance of initial evidence showing that functional connectivity may serve as a basis for cognitive impairments in this patient population.
Even more, these findings can provide a foundation and guide for future, more in-depth research.
The study, “Association of Sinonasal Inflammation With Functional Brain Connectivity,” was published online in JAMA Otolaryngology-Head & Neck Surgery.