Sudden sensorineural hearing loss: Is there a connection with inner ear electrolytic disorders? A literature review

Abstract

Electrolytic disorders of the inner ear represent a model that could be implicated in partially explaining the pathogenesis of sudden sensorineural hearing loss (SSNHL). Different types of electrolytes and different inner-ear loci are involved in cochlear homeostasis physiologically, to ensure the maintenance of an ion-balanced cochlear environment allowing a normal hair cell function. It has been hypothesized that a sudden loss of endocochlear potential, due to a rapid disruption of the inner ear fluid osmolality, could be responsible for a deterioration of the hearing function caused by damaged hair cells. The aim of this paper was to review the current literature and identify sources which might validate/fortify the hypothesis that inner ear electrolytic disorders have a role in the etiopathogenesis of SSNHL. The data in the literature underline the importance of ionic homeostasis in the inner ear, but they do not support a direct link between SSNHL and electrolyte disorders/imbalances. There is marginal evidence from otoacoustic emissions research that an indirect link might be present.

Gender differences in audio-vestibular disorders

“…5 Data from studies investigating the prognostic role of gender on hearing recovery after SSNHL show a correlation with a higher hearing threshold improvement in men compared to women, although not statistically significant. 5…”

“…In the United States, the incidence of SSNHL is reported to be 5–20 out of 100,000 with an overall male preponderance, and approximately 90% of the SSNHL cases remain idiopathic. 5 For the latter, a number of etiopathogenetic hypotheses have been suggested, such as vascular disorders, viral infections, immunological diseases, endolymphatic hydrops, labyrinthine membrane ruptures and electrolytic anomalies. 5 Data from studies investigating the prognostic role of gender on hearing recovery after SSNHL show a correlation with a higher hearing threshold improvement in men compared to women, although not statistically significant.…”

Comparison of Sudden Sensorineural Hearing Loss with Tinnitus and Short-Term Tinnitus

“…This suggested that tinnitus patients with normal hearing threshold may have cochlear damage and all tinnitus patients may have hidden hearing loss. Some studies believed that some SSH patients cannot elicit DPOAE, which may be due to the damage of cochlear hair cells in SSH patients [ 15 ]. These conclusions suggested that tinnitus patients and SH patients may have similar pathology and pathogenesis, which can also explain that why there is no statistical difference between SSH and STT in the results of RI, THI, and VAS in this study.…”

Is Cyclosporine Ototoxic?

“…Also, it is known that cyclosporine can cause hypomagnesemia, and magnesium appears to be an important cation in the auditory system. Magnesium deficiency has been linked to noise-induced hearing loss, ototoxicity, and sudden sensorineural hearing loss (SSNHL) (20,21). The exact mechanism by which magnesium deficiency can cause hearing loss is not fully understood (22).…”