Influence of Auditory-Vestibular Function in Type 1 Diabetes Mellitus: A Systematic Review

Abstract

Diabetes mellitus (DM) is one of the metabolic disorders which is manifested by hyperglycemia brought on by abnormalities in insulin secretion, insulin action, or both. Type 1 DM occurs due to beta cell loss and absolute or relative insulin insufficiency, which result in hyperglycemia and hypoinsulinemia. Individuals with type 1 DM do experience dizziness, tinnitus, and hearing loss. The vestibular-cochlear abnormalities seen in these individuals have been linked to angiopathy and neuropathy due to diabetes mellitus. The present study aimed to systematically review the findings of published literature in terms of influence on audio-vestibular system due to type 1 diabetes mellitus. There are different databases (PubMed, Google Scholar, Scopus, & Web of Science) which were searched and identified 16,201 articles based on Booleans used. Out of 16,201 articles, there are 27 articles selected based on the inclusion and exclusion criteria for the study. Out of 27 full-length articles, 20 articles were related to auditory system and 7 articles were related to vestibular system. Overall, studies related to the assessment of auditory system based on both conventional and advanced audiological assessment (pure tone audiometry, high frequency audiometry, immittance, otoacoustic emission, click evoked ABR and frequency following response, and auditory late latency response) reported mixed finding in individuals with T1 DM. Studies reported with or without sensorineural hearing loss including involvement of peripheral and central auditory system. Similarly, vestibular assessment (behavioral vestibular tests, cVEMP, ENG, & vHIT) reported peripheral and central vestibular impairment due to T1 DM. the hyper or hypo-function of the vestibular system are reported in the individuals with type 1 DM. Studies also reported temporal processing deficit in individuals with type 1 DM apart from impaired quality of life. The primary reason for these changes if any reported in the studies are possibly due to reduced conduction efficiency result from demyelination, and/or neural dys-synchrony. Further, the subtle auditory processing deficit could also be one of the reason for the abnormalities noticed in the type 1 DM. Moreover, despite clinically normal audiometric thresholds, neural deficits are reported in the individuals with type 1 DM. Hence, present review suggests regular follow-up for audio-vestibular assessment of those individuals having type 1 DM for early identification and effective management of the deficits if any.