Conductive and mixed conductive/sensory hearing loss

A bone conduction implant (BCI) is used to treat 2 basic problems: conductive and/or mixed hearing loss and deafness in one ear (single-sided deafness). These devices are considered when use of a conventional (air-conduction hearing aid) is not possible. For the case of conductive or mixed hearing loss, they are used most commonly in patients with chronic ear infections, cholesteatoma, and chronic otorrhea in which the diseased eardrum and/or middle ear ossicles are not able to conduct sound to the cochlea and use of a conventional hearing device often is not possible. The other common situation is congenital aural atresia in which absence of the ear canal and eardrum causes conductive hearing loss and a conventional hearing aid cannot be used.

Before Baha, the only device available to treat these situations was a conventional bone conduction hearing aid. This device consists of a bone conduction hearing aid (vibrator) attached to a headband (see the image below). These devices, while very helpful over the years, have several inherent disadvantages that limit their benefit and their acceptance, including the following:

• Discomfort caused by the constant pressure of the vibrator against the scalp
• Poor sound quality and volume caused by the indirect and variable coupling of the vibrator to the skull due to intervening hair and scalp tissues
• Variable and unstable positioning affecting the quality of transduction
• Bilateral use is not possible
• Poor aesthetics

Audiometric Testing