Audiological characteristics and exploratory treatment of a rare condition of acute-otitis-media-associated sudden sensorineural hearing loss

BACKGROUND Acute otitis media(AOM)is a common disease that is more prevalent in children.Most studies concerning AOM-associated sudden sensorineural hearing loss are case reports and retrospective in nature,hence the etiology of AOM-associated sudden hearing loss has not been fully established.AIM To analyze audiological characteristics of AOM-associated sudden hearing loss and evaluate efficacy of combined tympanostomy tube placement(TTP)and intratympanic methylprednisolone.METHODS Eight adult patients who were diagnosed with AOM-associated sudden hearing loss and ineffectively treated by conventional medical therapy were enrolled in this study.Basic data were collected,and pure tone audiometry was performed to assess the audiological characteristics.Combination therapy with TTP and intratympanic methylprednisolone injection was given to the patients.RESULTS Mixed or sensorineural hearing loss was observed at high frequencies(2–4 kHz).All the cases in this study were cured after TTP and intratympanic methylprednisolone.After treatment,the average hearing threshold at affected frequencies was significantly lower than those in the pretreatment group(P<0.05)and was similar to that in the healthy ears(P>0.05).CONCLUSION AOM rarely induces sudden sensorineural hearing loss.Combination therapy with TTP and intratympanic methylprednisolone injection may be effective after failure of conventional medical treatment.

An efficient strategy for establishing a model of sensorineural deafness in rats

Ototoxic drugs can be used to produce a loss of cochlear hair cells to create animal models of deafness. However, to the best of our knowledge, there is no report on the establishment of a rat deafness model through the combined application of aminoglycosides and loop diuretics. The aim of this study was to use single or combined administration of furosemide and kanamycin sulfate to establish rat models of deafness. The rats received intravenous injections of different doses of furosemide and/or intramuscular injections of kanamycin sulfate. The auditory brainstem response was measured to determine the hearing threshold after drug application. Immunocytochemistry and confocal microscopy were performed to evaluate inner ear morphology. In the group receiving combined administration of furosemide and kanamycin, the auditory brainstem response threshold showed significant elevation 3 days after administration, higher than that produced by furosemide or kanamycin alone. The hair cells showed varying degrees of injury, from the apical turn to the basal turn of the cochlea and from the outer hair cells to the inner hair cells. The spiral ganglion cells maintained a normal morphology during the first week after the hair cells completely disappeared, and then gradually degenerated. After 2 months, the majority of spiral ganglion cells disappeared, but a few remained. These findings demonstrate that the combined administration of furosemide and kanamycin has a synergistic ototoxic effect, and that these drugs can produce hair cell loss and hearing loss in rats. These findings suggest that even in patients with severe deafness, electronic cochlear implants may partially restore hearing.