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Glossary: B

Battery tester

Used to check how much power is left in a battery.

Bilateral deafness

Hearing loss is both ears.

Bilingual support worker (or bilingual support assistant)

This could be a person employed by a school to work with children whose first language is not English, or a person who works alongside a speech and language therapist to facilitate the delivery of speech and language therapy services to individuals in the language of their choice.


To use a different type of hearing instrument in each ear is a bimodal fitting. For example using a cochlear implant and hearing aid together on opposite sides. 


Hearing with both ears

Bluetooth wireless accessories

Bluetooth is wireless communication technology.  It can be used with hearing aids and cochlear implants as a wireless loop system.  Bluetooth is now a common feature of mobile phones, and NDCS loans out Bluetooth loop systems through our Technology Test Drive service.

Bone anchored hearing aid (BAHA)

A bone anchored hearing aid (BAHA) is a type of bone conduction hearing implant (BCHI) clips onto a titanium screw implanted into the skull-bone behind the ear. Sound is transmitted by vibration through the skull-bone and into the cochlea (inner ear). 

Bone conduction hearing aid

Bone conduction hearing aids can be worn on metal or soft fabric headbands. They use a vibrating pad that allows sound to be conducted through the bone rather than through the middle ear. The vibrator is worn behind the ear, resting on the mastoid bone (part of the skull behind the ear). They are suitable for children who have conductive hearing loss and have problems wearing behind-the-ear hearing aids.  

Bone conduction hearing implant (BCHI)

A bone conduction hearing implant is designed for people who have a functioning cochlear but the middle or outer part of the ear prevents the information reaching the cochlea in the usual way. It consists of a sound processor that is held on the head behind the ear. This might be clipped to a fixture, known as an ‘abutment’, a small titanium screw that has been implanted in the skull just behind the ear (known as a bone anchored hearing aid or system) or with a magnet holding the processor in place. This allows sound to be conducted through the bone rather than through the ear canal and middle ear. This allows sound waves to be transmitted directly to the cochlea in the inner ear. 

Bone conduction hearing tests

Auditory Brainstem Response (ABR), Visual Response Audiometry (VRA) and Pure Tone Audiometry (PTA) can also be tested using bone-conduction.  A small vibrating device is placed behind the child's ear.  This passes sound directly to the inner ear through the bones in the head.  This technique is useful for identifying whether a hearing loss is conductive or sensorineural.

British Sign Language (BSL)

Over 70,000 people within the British Deaf community use BSL. It is a visual language using hand shapes, facial expressions, gestures and body language to communicate. BSL is an independent, complete language with a unique vocabulary. The grammatical structure of BSL is different from that of written and spoken English. Just like other languages, BSL has evolved over time and developed regional and national dialects. 


Ofcom, the communications regulating body, sets targets for the number of programs with subtitles each TV channel must provide.