Inner Ear Dysfunction in Thyroid Disease: A Scoping Review

Background and Objectives: Sensorineural hearing loss (SNHL) is influenced by various causes, including thyroid diseases. For example, hypothyroidism and thyroid autoimmunity can damage the inner ear through hormonal, immune, and vascular mechanisms. Vestibular disorders like Ménière's disease (MD) and benign paroxysmal positional vertigo (BPPV) also show possible associations with thyroid dysfunction. Materials and Methods: A review following PRISMA guidelines searched PubMed, Scopus, and Google Scholar for studies linking thyroid disorders with inner ear dysfunction. Results: Out of 985 screened records, 30 studies met inclusion criteria, involving various thyroid disorders, primarily hypothyroidism and autoimmune thyroiditis. Scientific evidence supports a correlation between hypothyroidism and hearing impairment. However, some studies also suggest a link between hyperthyroidism and inner ear disorders, particularly focusing on the role of autoimmunity in this context. Concerning vestibular dysfunction, the available studies are less abundant and support a significant association between thyroid disease and Meniere's disease. Conclusions: There is a clear correlation between hypothyroidism and auditory function. A substantial body of literature also supports an association with vestibular disorders, although some discrepancies remain. Further research is needed to elucidate the underlying pathophysiological mechanisms (e.g., autoimmune, vascular, metabolic) involved with this correlation.