A Novel Way of Stimulation of the Inner Ear via Labyrinthotomy with Fully Implantable Active Middle Ear Implant, Carina

The aim of this case report is to demonstrate the effectiveness of Carina for the treatment of mixed hearing loss by stimulation of the inner ear via the endosteum of the cochlea. The left ear of a 55-year-old man with bilateral mixed hearing loss was implanted with Carina. Due to absence of middle ear ossicles and oval and round windows, the transducer was coupled with the endosteum of the cochlea. A significant improvement was observed in the pure tone average after Carina application. Carina and a conventional hearing aid yielded similar amplification in the low frequencies (250 Hz to 1 kHz). The functional gain with Carina was better than that with the conventional hearing aid in the middle (2 kHz) and high (4 and 6 kHz) frequencies, by 15dB, 5dB, and 25dB, respectively. Speech reception threshold in the free field was 80 dB HL without the hearing aid, 60 dB HL with the hearing aid, and 50 dB HL with Carina. Two-syllable speech discrimination scores increased to 40% and 56% in noise and quiet, respectively. According to International Outcome Inventory for Hearing Aids questionnaire, the patient scored 24 with the hearing aid and 32 with Carina. Stimulation of the inner ear with Carina though the endosteum of the cochlea seems to be an efficient and alternative way to amplify hearing.