Impact of Hearing Loss on Memory Loss in Patients With Self-Reported Olfactory Dysfunction

Introduction The association between hearing loss and dementia, and olfactory dysfunction (OD) and dementia, respectively, is well-elucidated. Several neurodegenerative diseases, including Alzheimer's disease and Parkinson's disease, impact the olfactory system early in their progression. Despite these established correlations, the independent effect of hearing loss on memory in patients with self-reported olfactory dysfunction is poorly elucidated, which this study aims to investigate, especially in light of the prevalence of anosmia post-COVID-19. Methods A total of 591 records of adult patients with self-reported olfactory dysfunction without a history of traumatic brain injury (TBI) from 2015 to 2020 from a single academic institution were analyzed. Patients were stratified based on demographic, memory loss (including mild cognitive impairment (MCI)), and clinical factors. Univariate and multicollinearity analyses assessed for correlations, with significant covariates utilized in a logistic regression model. Results In univariate analyses, hearing impairment (p<0.001), history of stroke (p<0.001), coronary artery disease (CAD) (p<0.001), hypertension (HTN) (p<0.001), and obstructive sleep apnea (OSA) (p=0.020) were significant. Primary language spoken, smoking history, myocardial infarction (MI), and diabetes mellitus (DM) were not significant. In logistic regression, hearing impairment was significantly associated with memory loss (p<0.001). Other significant covariates included stroke (p=0.004), CAD (p=0.022), and HTN (p<0.001). Conclusions Our results show that hearing impairment is significantly associated with memory loss, specifically in patients with self-reported olfactory dysfunction. This highlights the increased risk of memory loss in this population, underscoring the need for further research into screening and pathophysiology of memory loss in hard-of-hearing patients with olfactory dysfunction post-COVID-19.