Bone-conduction devices, also referred to as bone-anchored hearing aids, bone-conduction stimulators, or bone-conductor implants, are devices that are implanted or worn. These devices directly transmit sound vibrations to the inner ear, bypassing the ear canal and the middle ear, and stimulating the inner ear through the skull.
These types of hearing devices are suitable for individuals with conductive hearing loss, mixed hearing loss, or single-sided deafness. Bone-conduction devices are good alternatives for individuals who cannot wear hearing aids due to problems in the outer or middle ear.
Bone-conduction devices are comprised of three parts: an external audio processor that contains the battery, microphone, and digital signal processor. These devices can be worn behind the ear and hidden underneath the hair, or be applied to a tooth like a retainer. Some types require a surgically implanted titanium abutment placed behind the ear and embedded in the temporal bone. The titanium abutment secures the external audio processor in place.
The audio processor records sound and converts it into signals, which are then transferred through the skin to the titanium implant. The implant transforms the signals into mechanical vibrations that are transmitted to the surrounding bone. The bone conducts the vibrations to the inner ear, where they are converted and transmitted as impulses to the auditory nerve, much like the natural hearing process.
Some bone-conduction devices use magnetic connection. A magnet is implanted against the skull behind the ear and painlessly anchors the sound processor directly to the scalp.