Acoustic feedback: Unpleasant whistling or squealing noise that others can hear - created when sound amplified by a hearing aid gets picked up by its microphone.
Anvil: See 'Incus'.
Audiometer: A machine used to test hearing. Basic screening audiometers give an indication of how well someone can hear. Diagnostic audiometers, found in most audiology departments, are able to provide a better picture of hearing ability - including the type of hearing loss.
Baha®: A special type of hearing aid that has a permanent physical connection to the bones of the skull.
BiCROS (hearing aid): A variation of the CROS hearing aid, for use by people who have a profound hearing loss in one ear as well as a significant loss in the other ear. A microphone picks up sound from behind the ear with the greater hearing loss and sends the signal (via a wire or by wireless technology) to a hearing aid worn on the better ear.
Bilateral hearing loss: A hearing loss in both ears.
Body Worn hearing aid: A hearing aid in which a small box is clipped on to clothes or put in the pocket. This box contains the microphone and working parts. It is connected by a lead to an earphone clipped into your earmould. Body-worn hearing aids may be suitable for people with sight problems, or problems using very small switches or buttons.
Bone conduction: Sound that is transmitted by, and heard through, the bones of the skull.
Cerumen: See 'Ear wax'
Cochlear implant: A type of hearing device in which electric currents corresponding to the sound signals that a person wants to hear are passed straight to the sensory cells of the inner ear (cochlea) via a surgically implanted electrode.
Conductive hearing loss: A type of hearing loss resulting from sound not reaching the inner ear properly. Conductive hearing loss happens when there is a problem conducting sound waves through the outer ear, tympanic membrane (eardrum) or middle ear (ossicles). This type of hearing loss can occur together with sensorineural hearing loss or alone.
CROS (hearing aid): A special type of hearing aid, made up of two parts, for use by people with a unilateral hearing loss. A microphone picks up sound from behind the ear with the hearing loss and sends the signal (via a wire or by wireless technology) to a hearing aid worn on the other ear. See also: 'BiCROS (hearing aid)'
DECT phone: A landline telephone in which the base unit is connected by wire to a standard telephone socket but by radio signals to the handset, enabling it to be carried around the home.
Decibel: Widely used in sound measurement (abbreviated to dB). Strictly speaking, a decibel rating relates to the ratio of the strength of a particular sound to a standard reference level, but in practicval terms, it is used as an unit.
Ear drum: See 'Tympanic Membrane'
Earmould: A contoured ear fitting used to feed the sound output from a hearing aid into the ear. Earmoulds are usually custom-made in acrylic to fit a particular ear, but occasionally may be made of other (sometimes non-allergenic) materials.
Feedback: The high-pitched whistling sound caused by the hearing aid's microphone picking up the output of the hearing aid and re-amplifying it. Well fitted earmoulds can eliminate the problem of feedback.
Hair cells: The sensory cells of the inner ear, which are topped with hair-like structures (called stereocilia) which convert sound energy into nerve impulses.
Hammer: See 'Malleus'
Hearing Aid:An electronic device that amplifies sound. They are usually worn behind or inside the ears by people with a hearing loss.
Hearing Aid Council (HAC): The Government body that regulates the private hearing aid market. All hearing aid dispensers in the UK must be registered with the HAC and meet their standards of education, training and conduct.
Hearing loss: A full or partial decrease in the ability to detect or understand sounds.
Hearing threshold: The minimum sound level of a pure tone that an individual is able to hear in a noiseless environment. In audiology, hearing thresholds are tested at a number of different frequencies.
Induction loop: A complete circuit (loop) of wire through which an electric current corresponding to a sound signal is passed. The current causes the generation of a magnetic field, which can be received on a hearing aid set to 'T'.
Lip reading: A way of understanding speech by visually interpreting the movements of the lips, face and tongue of the speaker, along with other information provided by the context, language, and any residual hearing.
Localisation: Refers to a person's ability to identify the location or origin (in terms of distance and direction) of a detected sound.
Mastoid bone: The area of bone directly behind each ear.
Middle Ear The air-filled cavity containing the ossicles and tympanic membrane, the function of which is to transfer sound energy from the outer ear to the inner ear. The middle ear is connected to the back of the nose by the Eustachian tube.
Otoscope: A small torch-like instrument used for looking into the ear canal.
Pinna: The visible part of the ear, outside of the head (also referred to as the auricle).
Presbycusis: The natural, gradual loss of hearing which is the result of the ageing process. Also known as 'age related hearing loss'.
Pure Tone Audiometry: Pure tone audiometry (PTA) is the most widely used hearing test for identifying hearing threshold levels and enables the determination of the degree, type and configuration of a hearing loss. The test is carried out using an Audiometer.
Real Ear Measurements (REMs):
Relay service: An operator service that allows people who are deaf or hard of hearing to place calls to standard telephone users via a keyboard or assistive device.
Sign Language: A form of language used by deaf and hard of hearing people which uses visible hand gestures rather than voice to convey meaning.
Stirrup: (See 'Stapes')
Tinnitus: The sensation of noise within the ear or head when there is no external sound source. The noise heard differs from person to person, but is often described as a ringing, buzzing or roaring sound. Tinnitus is often associated with many forms of hearing loss and noise exposure.
Tinnitus relaxer: A sound enrichment device that can help to relieve tinnitus through relaxation.
Unilateral hearing loss: A hearing loss in one ear only.
Vestibular System: The system in the inner ear that is concerned with controlling balance.