A Bone Anchored Hearing Aid (BAHA) is a surgically implantable device. It is a type of hearing aid that works by bone conduction; this means that the sounds are transferred through the bone to the cochlea (hearing organ) by mechanical vibration. It is used to treat hearing loss in people that are unable to wear conventional hearing aids.
The BAHA system is made up of three parts; a titanium screw fixture, an abutment, and an external hearing aid processer that is detachable. The titanium screw fixture and abutment are surgically implanted into the skull located slightly about and behind the ear. The external processor has a microphone that picks up sounds in the environment, which are then converted into mechanical vibrations that are transmitted through the skull to the inner ear and, from there, the brain. These processes by-passes the ear canal and the middle part of the ear and use the inner ear function only.
People who are unable to wear conventional hearing aids may benefit from wearing a BAHA. A BAHA could be beneficial for people with chronic middle ear disease, malformation of the ear canal or middle ear and unilateral sensorineural hearing loss or single-sided deafness. A BAHA pre-operative assessment is essential. This involves a hearing test and speech testing with and without a BAHA test unit to assess the benefit that may be obtained.