Cochlear implantation in auditory neuropathy spectrum disorders: role of transtympanic electrically evoked auditory brainstem responses and serial neural response telemetry.

OBJECTIVE: To evaluate the utility of pre-operative transtympanic electrically evoked auditory brainstem responses and post-operative neural response telemetry in auditory neuropathy spectrum disorder patients. METHODS: Four auditory neuropathy spectrum disorder patients who had undergone cochlear implantation and used it for more than one year were studied. All four patients underwent pre-operative transtympanic electrically evoked auditory brainstem response testing, intra-operative and post-operative (at 3, 6 and 12 months after switch-on) neural response telemetry, and out-patient cochlear implant electrically evoked auditory brainstem response testing (at 12 months). RESULTS: Patients with better waveforms on transtympanic electrically evoked auditory brainstem response testing showed superior performance after one year of implant use. Neural response telemetry and electrically evoked auditory brainstem response measures improved in all patients. CONCLUSION: Inferences related to cochlear implantation outcomes can be based on the waveform of transtympanic electrically evoked auditory brainstem responses. Robust transtympanic electrically evoked auditory brainstem responses suggest better performance. Improvements in electrically evoked auditory brainstem responses and neural response telemetry over time indicate that electrical stimulation is favourable in auditory neuropathy spectrum disorder patients. These measures provide an objective way to monitor changes and progress in auditory pathways following cochlear implantation.

An unusual case of ear mould impression material as a foreign body in the middle ear: case report.

BACKGROUND: The occurrence of retained ear mould impression material is rare and can lead to complications. The current case report describes one such complication, where the silicone impression material used to take the impression of the ear canal flowed into the middle ear through the pre-existing tympanic membrane perforation. Five days later, the patient presented with worsened hearing and blood-tinged discharge from the ear. Ear microscopy revealed a greenish foreign body in the middle ear. CASE REPORT: The foreign body was removed by tympanotomy and the perforation repaired using a temporalis fascia graft. A hearing aid was prescribed after ensuring that the perforation had healed. CONCLUSION: It is essential that the audiologist perform a basic otological examination before prescribing a hearing aid and preparing an ear mould. A clinical approach algorithm for audiologists, for prior to taking an impression, is suggested.