Dysfunction of the peripheral and central auditory pathway in patients with type 1 diabetes mellitus

Although auditory alterations are not a typical symptom of diabetes mellitus (DM), they can occur in patients with type 1 DM. The findings of previous studies are controversial, because the frequency and degree of hearing loss varies, and quite often alterations are still subclinical. The typical test used to detect and manage hearing loss is the audiogram, but this test alone is only capable of detecting alterations due to injury of the inner hair cells and/or alterations in the central auditory pathway. However, auditory alterations resulting from a dysfunction that is still subclinical are only able to be detected through electrophysiological auditory tests, such as the otoacoustic emissions (OAE) and the auditory brainstem response (ABR) tests. Thus, the purpose of this paper is to review the studies that utilize the OAE and ABR tests, and to verify if the dysfunction is cochlear and/or neural in patients with type 1 DM. The findings of this review demonstrate that patients with type 1 DM can have auditory alterations stemming from a central cochlear origin. Following this finding, early diagnosis is very important in order to implement preventative treatments and initiate therapy.