Non-implantable Artificial Hearing Technology

Abstract

A hearing aid is a sound-amplifying device used for aiding hearing-impaired individuals and compensating hearing loss. With the development of science and technology, tremendous strides have been made in hearing aid technology. The history of hearing aids can be divided into five eras: acoustic era, carbon era, vacuum tube era, transistor and integrated circuit era, and digital era. It mainly comprises microphone, amplifier, receiver, battery, volume and tone control buttons, and other electroacoustic components, which can be classified into following types: pocket hearing aids, BTE hearing aids, ITE hearing aids, ITE hearing aids, completely/invisible-in-canal hearing aids (CIC and IIC), and other types. Of them, one bone-anchored hearing aid (BAHA) softband is mainly applicable to children under 5 years old who cannot wear bone-anchored hearing aids in congenital bilateral external auditory canal occlusion. BAHA system comprises three components: a titanium implant (fixture screw), an external abutment (bridging screw), and a sound processor consisting of a microphone and a transducer. The following procedures are included in hearing aid fitting: medical history collection, trial, fitting, ear sample taking, hearing aid refitting, evaluation, practical instruction, and follow-up care. Children should be helped to select hearing aid as early as possible, and for those with congenital hearing loss or prelingual deafness, it can be added assessment of speech development while preventing the child from swallowing hearing aids or batteries by mistake. Speech recognition score (SRS) test is very important in elderly patients, because the speech hearing and pure-tone hearing of presbycusis are often inconsistent. After the hearing aid is selected, the effect evaluation and related rehabilitation should be carried out timely.