Cognitive Dysfunction in Chronic Rhinosinusitis: A Scoping Review.

BACKGROUND: Cognitive dysfunction is increasingly recognized as an extra-nasal manifestation of chronic rhinosinusitis (CRS). This scoping review characterizes the primary evidence on cognition in adult CRS, covering measures, treatment response, and incident dementia. METHODS: We searched EMBASE, PubMed/MEDLINE, Web of Science, the Cochrane Library, CINAHL, and Global Index Medicus through May 2026 using a MeSH and free-text strategy. Inclusion criteria include primary studies of adult CRS with a formal clinical diagnosis (AAO-HNS, EPOS or ICD-coded) reporting at least one validated cognitive measure or recognized cognitive impairment. Two reviewers screened independently. Animal studies, reviews, conference abstracts, and non-CRS populations were excluded. PRISMA-ScR reporting was performed; heterogeneity precluded meta-analysis. RESULTS: Twenty-four primary studies met inclusion criteria. Adults with CRS perform worse than controls on subjective (Cognitive Failures Questionnaire [CFQ], Neuro-QoL) and objective (Montreal Cognitive Assessment [MoCA], Automated Neuropsychological Assessment Metrics [ANAM], eye movement assessment, P300) cognitive instruments. Deficits correlate with disease-specific QoL severity (SNOT-22, Rhinosinusitis Disability Index [RSDI]). Cognitive measures improve after medical therapy or endoscopic sinus surgery. Two resting-state fMRI analyses identified altered orbitofrontal-precuneus connectivity scaling with sinonasal inflammation. Dementia results are mixed: a UK Biobank analysis (7176 CRS cases among 364,945 participants) reported increased Alzheimer disease risk (HR 1.33), while two Korean cohorts and a 2025 meta-analysis found no association. CONCLUSION: Adults with CRS show measurable cognitive dysfunction that may improve with treatment, with a plausible neuroinflammatory pathophysiology. Whether this translates to incident dementia is contested. Outcome heterogeneity limits synthesis; therefore, development of a CRS-specific cognitive measurement set is recommended.