A bone-anchored hearing device is a hearing device that relies on direct bone conduction to transmit sound.
This surgically implanted device bypasses the auditory canal and middle ear, utilizing bone as a pathway for sound to reach the inner ear. It’s an alternative for people with chronic ear infections, congenital external auditory canal atresia and single-sided deafness. These patients usually do not benefit from conventional hearing aids.
How Do Bone Anchored Hearing Devices Work?
In a person with normal hearing, sound enters the external ear and travels down the ear canal through the middle ear to the cochlea, or inner ear. This process is called air conduction.
For individuals with certain types of hearing loss, the sound is unable to travel down these pathways. Bone anchored devices take advantage of the skull’s natural conductive abilities by sending sound vibrations directly to your inner ear, bypassing the auditory canal and middle ear completely.
The bone-anchored device is made up of three components: a titanium implant, an external abutment and a sound processor. Once the surgical implant is in place, it gradually fuses with the skull bone over a period of several months in a process known as osseointegration.
One month post-surgery the device is ready to be fitted and programmed. The sound processor directly connects to the external abutment and transmits vibrations to the implant, where vibrations in the skull and inner ear stimulate the Hair cells and nerves responsible for hearing. Newer versions of the BAHA utilize an internal magnet (Attract) to retain the external sound processor, rather than having an abutment through the skin.
The OSI – Osseointegrated Steady-state Implant – is another new development in which the vibrating component is implanted under the scalp and connected to the titanium implant. An external button type sound processor is then worn to provide the power and signal.
Who Can Benefit from Bone Anchored Hearing Devices?
Candidates for these devices are typically patients with conductive and mixed hearing losses or those with unilateral (single-sided) hearing loss.
If you experience chronic ear infections that do not respond to treatment, you may find the system particularly beneficial. Conventional hearing aids can aggravate the condition due to humidity and moisture building up in the ear canals. Those with congenital ear defects (such as ear canals that are narrow or absent) are good candidates, as well.