A bone conduction device (BCD) is a type of hearing aid that transmits sound directly to the inner ear through the bones of the skull, bypassing the outer and middle ear. It is designed for people who have conductive hearing loss or single-sided deafness, where the outer or middle ear is damaged or missing, but the inner ear and auditory nerve are intact.
A BCD consists of a small processor that sits behind the ear and a vibrating transducer that is placed on the bone behind the ear or on the mastoid bone. The processor picks up sound from the environment and converts it into vibrations, which are then transmitted through the skull bone to the inner ear, where they are interpreted as sound.
There are several types of bone conduction devices, including:
1. Headband devices – worn around the head with a vibrating pad resting on the bone behind the ear.
2. Adhesive devices – attached directly to the skin over the bone behind the ear.
3. Implantable devices – surgically implanted under the skin, with a vibrating transducer attached to the skull bone.
Bone conduction devices are often recommended for people who cannot use traditional hearing aids due to ear canal or middle ear problems, or for those who have experienced little benefit from traditional hearing aids. They can also be used by people with normal hearing in one ear and hearing loss in the other ear.