Biomarkers for Inner Ear Disorders: Scoping Review on the Role of Biomarkers in Hearing and Balance Disorders

The diagnostics of inner ear diseases are primarily functional, but there is a growing interest in inner ear biomarkers. The present scoping review aimed to elucidate gaps in the literature regarding the definition, classification system, and an overview of the potential uses of inner ear biomarkers. Relevant biomarkers were categorized, and their possible benefits were evaluated. The databases OVID Medline, EMBASE, EBSCO COINAHL, CA PLUS, WOS BIOSIS, WOS Core Collection, Proquest Dissertations, Theses Global, PROSPERO, Cochrane Library, and BASE were searched using the keywords “biomarker” and “inner ear”. Of the initially identified 1502 studies, 34 met the inclusion criteria. The identified biomarkers were classified into diagnostic, prognostic, therapeutic, and pathognomonic; many were detected only in the inner ear or temporal bone. The inner-ear-specific biomarkers detected in peripheral blood included otolin-1, prestin, and matrilin-1. Various serum antibodies correlated with inner ear diseases (e.g., anti-type II collagen, antinuclear antibodies, antibodies against cytomegalovirus). Further studies are advised to elucidate the clinical significance and diagnostic or prognostic usage of peripheral biomarkers for inner ear disorders, filling in the literature gaps with biomarkers pertinent to the otology clinical practice and integrating functional and molecular biomarkers. These may be the building blocks toward a well-structured guideline for diagnosing and managing some audio-vestibular disorders.

Incidence of Inner Ear Disorders in Various Forms of Acute Otitis Media in ENT Practices in Germany

Objective: The aim of this study was to determine the incidence of inner ear involvement in various forms of acute otitis media (AOM) in ear, nose, and throat (ENT) practices in Germany. Methods: Patients who had been diagnosed with various forms of AOM in the years 2010 to 2017 were enrolled in the study from a nationwide, representative practice database (Disease Analyzer, IQVIA). In these patients, the incidence of simultaneous or subsequent inner ear disorders (IED) was determined within 7 days and within 12 months from the date of an AOM diagnosis. Results: A total of 286 186 patients with AOM were enrolled. The most frequent diagnoses were “nonsuppurative otitis media, unspecified” (47.6%) and “otitis media, unspecified” (39.0%). The diagnoses of hemorrhagic bullous myringitis (BM) or influenza-induced AOM were very rarely found in the database. The highest incidence of IED after 7 days and 12 months was found in “nonsuppurative otitis media, unspecified” (7.7% and 15.9%, respectively), followed by “otitis media, unspecified” (5.6% and 13.5%, respectively). The incidences of the most frequent IED “hearing loss, unspecified” and “sensorineural hearing loss, unspecified” increased proportionally with increasing patient age, while the rare diagnoses of “labyrinthitis” and “ototoxic hearing loss” were evenly distributed among the age groups. Conclusion: In ENT practices in Germany, both various forms of AOM, as well as simultaneous or subsequent IED, are mostly being coded in an unspecific way, while specific forms such as hemorrhagic BM, influenza-induced AOM, and labyrinthitis are coded very rarely. Older patients have a higher risk of IED in AOM. A visit due to AOM seems to be a regular occasion for the initial diagnosis of hearing impairment in the elderly individuals. The highest risk of IED was found in nonsuppurative AOM.