Glossary - A guide to Hearing Loss

A

Acoustic neuroma A benign tumour which grows in the lining of the auditory nerve.

This nerve is responsible for our ability to hear and balance. This tumour develops gradually over time and compresses the auditory nerve, resulting in problems with balance and hearing loss.

Acoustic trauma

The name given to noise related damage of the inner ear.

Acute otitis media

A short lived, middle ear infection: as opposed to chronic otitis media which is repeated ear infections.

Age-related hearing loss

See presbycusis.

Air conduction

The passage of sounds through the outer, middle and inner ear.

Amplifier

A device which increases the volume of a sound: a component in hearing aids that converts sounds into electrical signals which are amplified for the benefit of the wearer.

Analogue hearing aid

An older type of hearing aid which detects sounds, via a microphone and changes these into electrical impulses. These impulses are then boosted in volume via the amplifier and channelled towards the ear.

Anvil

Also known as the ‘incus’: the second of three tiny bones within the middle ear.

Audiological evaluation

A series of tests which can assess an individual’shearing ability. They are often used to determine hearing loss and to what extent.

Audiology

The study of hearing.

Auditory nerve

This transmits information from the cochlea to the brain.

This nerve consists of two divisions: the cochlea nerve which transfers electrical signals to the brain which are interpreted as sound: and the vestibular nerve which controls our sense of balance.

Autoimmune inner ear disease

A condition in which the body’s immune system attacks the mechanisms of the inner ear, affecting hearing and balance.

B

Background noise

The name given to any sound which distracts and/or prevents an individual from following a conversation. This is especially a problem for someone who is deaf or has a degree of hearing loss.

Balance

The mechanism which enables you to position your body in relation to your environment. It also controls movements such as running, jumping and walking and helps you to focus on objects whilst moving.

Behind the ear hearing aid

A type of hearing aid which fits behind the ear and enables sound to be transferred via the ear mould to the ear.

Bi-CROS hearing aid

This aid is designed for an individual with no hearing in one ear and partial hearing in the other ear. It takes the form of two hearing aids and works by sending sounds from the ‘bad’ear to the ‘good’ear where they are combined with amplified sounds in this ear.

Binaural hearing aid

Hearing aids worn in both ears.

Body-worn aid

An analogue hearing aid which the individual wears as a small box on their person. This box is connected via a wire to an ear piece through which sounds travel.

Bone-conduction hearing aid

Another analogue hearing aid which is designed for people who can’t wear a conventional hearing aid. Sounds are passed through the skull (via a headband) to the inner ear rather than through the ear canal as normal.

C

Cerumen

The medical name for ear wax. Channel

This refers to the series of electrodes used in a cochlear implant. These electrodes are arranged in pairs and are numbered in a particular way so that number ‘1’ is the lowest pitch.

Chronic otitis media

Repeated infections of the middle ear: this differs from severe acute otitis media

Cilia

Hair cells within the cochlea.

Cochlea

The ‘snail-like’part of the inner ear which helps to transmit sounds to the brain. This structure contains hair cells (cilia) which move as they detect sound and transform these into electrical signals. These signals are sent through the auditory nerve to the brain.

Cochlear implant

An electronic device which acts as a replacement for a damaged cochlea. If the hair cells have become injured or died then hearing is impaired: but this device bypasses this by using a set of electrodes to stimulate the auditory nerve and enable hearing.

Coding

Refers to the process within a cochlear implant in which sounds are collected, analysed and selected for stimulation of the electrodes.

Completely in the canal hearing aid

A smaller version of the ‘in the ear hearing aid’ which is practically invisible to the observer.

Conductive hearing loss

A form of hearing loss in which sounds are prevented from travelling through the outer ear to the middle ear and into the inner ear.

This can be caused by a build up of ear wax in the ear canal, an ear infection such as otitis media or a foreign body.

Conventional hearing aid

Another name for an analogue hearing aid.

CROS hearing aid

Similar to a Bi-CROS hearing aid: a type of device which is designed for people who have no hearing in one ear but normal hearing in the other.

A CROS hearing aid picks up sounds from the ‘bad’ear (no hearing) and sends these to the ‘good’ ear (normal hearing).

D

Deafness

A term used to describe a state of no or minimal hearing.

Decibel

A unit used to measure the volume of a particular sound: and the extent of someone’s hearing loss.

Digital hearing aid

A modern type of hearing aid which contains a microchip that processes sounds as ‘bits’rather than a continuous signal. This enables the wearer to distinguish between individual sounds or to control the types of sounds in a particular environment.

Distortion

The name given to poor or impaired sound reproduction: hearing aids are guilty of this as they all create a small amount of distortion.

Dizziness

A state in which the sufferer feels faint, light-headed and generally, unsteady on their feet. This can be a sign of a problem with their balance system.

E

Ear bud

A type of earphone which is designed to sit inside the ear rather than on top of it. Often used with MP3 players and iPods.

Ear canal

The pathway which runs from the outer ear to the ear drum. Ear wax (cerumen) is produced here. This canal contains millions of tiny hairs which stop germs and foreign bodies from reaching the ear drum. Ear drum

Also known as the tympanic membrane: a slim, tight, concave membrane which vibrates in response to sounds from the outer ear before sending these into the middle and inner ear.

Ear infection

This is caused by bacteria and germs which develop in the ear, leading to a build up of fluid within the ear.

The most common form of middle ear infection is otitis media. Ear mould

The plastic bit of a hearing aid which fits behind or inside the ear and enables sounds to be passed from the aid into the ear.

Ear wax

The medical name for this is cerumen: the yellowish/brown, waxy deposit which is produced by glands within the ear canal. This protects and cleans the ear. Eustachian tube The small tube which connects the middle ear to the back of the throat (near the pharynx). It helps to balance air pressures within the ear and remove naturally occurring fluids.

External ear

The part of the ear that you see, for example, the ear canal and the pinna.

F

Feedback

This refers to the high-pitched noise (squeal) which has ‘leaked’ from the hearing aid and has been detected by the microphone. This sound is amplified repeatedly until it reaches a maximum volume. Functional hearing loss

A type of hearing loss which is caused by psychological factors rather than physiological factors.

G

Glue ear

This can develop following chronic ear infection, such as otitis media. Fluid builds up in the Eustachian tube and becomes infected, turning into a thick, viscous substance – similar to glue. This blocks this tube and prevents the normal passage of sounds through the ear.

Hearing and balance are both affected.

Grommet

A small, plastic tube which in inserted into the ear drum to allow excess fluid to drain from the middle ear.

H

Hair cells

Also known as cilia: hair cells within the cochlea transform sounds into electrical signals; hair cells within the vestibular nerve respond to movement.

Hammer

Also known as the ‘malleous’: the first and biggest of the three bones within the middle ear.

Hard of hearing

Defined as a gradual loss of hearing.

Hearing aid

A device which amplifies sounds and sends these into the ear enabling a person to hear. There are two types of hearing aid: analogue and digital.

Hearing impaired

A term which has been used to describe people with hearing loss. However this has been superseded by the terms ‘hearing loss’and ‘hard of hearing’.

Hearing level

Normal hearing measured in decibels.

Hearing loss

A decline in hearing ability which ranges from mild through to severe or profound deafness.

Hereditary hearing loss

Hearing loss which has been passed down through generations of a family.

Hyperacusis

Hyper-sensitivity to particular sounds.

I

Idiopathic

If used to refer to hearing loss then it means that it has no known cause.

Incus

The medical term for the anvil – the second of three tiny bones in the middle ear.

Inner ear

The part of the ear nearest to the brain which controls hearing and balance. Sounds and balance signals are transformed into electrical impulses and sent to the brain via the auditory nerve.

In the canal hearing aid

A discreet type of hearing aid which sits inside the ear.

J

None at present.

K

None at present.

L

Labyrinth

The name given to the maze of fluid filled chambers within the ear (semi-circular canals) which are responsible for our ability to balance.

Lip-reading

A system in which someone watches the mouth of another person as they speak in order to better understand what they are saying. Used by people who are hard of hearing.

Loop system

Refers to a system used in public places which consists of a length of coil attached to an audio device which transmits sounds to people with hearing aids. Most hearing aids have a ‘T-setting’ (telecoil) which detects these sounds.

M

Malleous

The medical name for the ‘hammer’: the largest of the three bones within the middle ear, which touches the ear drum.

Masking

Refers to the process of using ‘white noise’or a low pitched sound to cover up another, often caused by tinnitus.

Mastoid bone

A part of the temporal bone (bone on the sides of the skull) which can be found behind your ear.

Meniere’s disease An imbalance in fluid levels within the inner ear. This affects balance and causes hearing loss. Meningitis

An inflammation of the membranes, called the ‘meninges’ which protect the brain and spinal card. There are two types of meningitis: viral and bacterial.

Middle ear

The part of the ear which lies between the outer ear and inner ear and contains three tiny bones called the ossicles. These transmit sounds from the middle ear into the inner ear via the oval window. Myringoplasty

A surgical procedure which involves the grafting of a piece of skin from above the ear onto a perforated ear drum –if this has failed to heal of its own accord. Myringotomy

A procedure which involves making a tiny incision in the ear drum to enable excess fluid to drain away following a chronic ear infection.

N

Noise

Unpredictable and erratic types of sounds.

O

Ossicles

The medical term for the three bones within the middle ear: the hammer (malleous), anvil (incus) and stirrup (stapes).

Otalgia

Technical name for ear ache.

Otitis externa

Infection in the outer ear which may include the ear canal. Often called ‘swimmer’s ear’.

Otitis media

This is where fluid develops in the Eustachian tube and becomes infected, inflaming the tissues within that tube. This tube becomes blocked which results in hearing loss.

Children are more prone to this infection than adults.

Otitis media with effusion

The medical name for ‘glue ear’.

Otorrhea

The name given to an infected discharge from the outer and middle ear.

Otorrhagia

Bleeding from the ear.

Otosclerosis

Abnormal growth of the stapes bone within the middle ear which results in hearing loss.

Ototoxic

The name given to a range of drugs in which one of the side effects is hearing loss. Ototoxic drugs include antibiotics, cancer drugs (chemotherapy), aspiring and anti-malarial medication.

Outer ear

The part of the ear which is visible to the naked eye and consists of the ear canal and the pinna. Sounds are detected here and passed into the ear towards the ear drum.

Oval window

A membrane which sits beneath the stapes and between the middle and inner ear.

P

Perforated ear drum

A rip or tear in the ear drum.

Pinna

The medical name for the external ear (the ‘shell-like’shape)

Presbycusis

Technical name for age-related hearing loss: a gradual form of hearing loss which is part of the ageing process.

Q

None at present.

R

Receiver

The small transmitter inside a hearing aid which directs sounds towards the ear.

Residual hearing

The name given to the amount of hearing a person has in response to hearing loss.

Rubella

Also known as German measles: a viral infection which, if it affects pregnant women, can result in hearing loss in the unborn baby.

S

Semi-circular canals

A set of three fluid filled canals within the inner ear which form the labyrinth. They help to regulate balance within an individual.

Sensorineural hearing loss

Hearing loss which occurs as a result of damage to the hair cells within the cochlea and/or the auditory nerve.

Sign language

A system of gestures and hand movements which are used to explain concepts instead of speech.

Sinusitis

Inflammation of the sinuses.

Speech processor

A component in a cochlear implant which transforms sounds into electrical signals and transmitted to the brain. The brain is able to interpret these as sound.

Stapedectomy

Surgery carried out on the stapes bone to treat otosclerosis.

Stapes

The medical term for the stirrup: the smallest of the three bones within the middle ear. This is the smallest bone in the human body.

Stirrup

Also known as the stapes.

T

Telecoil

A coil of wire within a hearing aid which enables it to detect sounds in a public space which has a loop system. Often called a ‘T-switch’ or ‘T-coil’.

Tinnitus

A series of noises heard in the ear (or head) such as whistling, buzzing, humming or shrieking which are usually the symptoms of an underlying condition.

Tinnitus masker

A device which produces ‘white noise’ or restful sounds to block out internal tinnitus sounds.

Tympanic membrane

The medical name for the ear drum.

U

Unilateral hearing loss

Hearing loss which has occurred in one ear only.

V

Vertigo

A condition caused by damage to the balance system of the inner ear. Characterised by a feeling of spinning, nausea and a general unsteadiness.

Vestibular system

The name given to the section of the inner ear which deals with balance, and includes the semi-circular canals.

Volume control

A switch or lever on a hearing aid which increases and decreases the volume of sound.

W

Wax

See ear wax.

White noise

A technical term for a type of sound which is similar to a hissing noise and maintains a constant level. Often used in tinnitus maskers.

X

None at present.

Y

None at present.

Z

None at present.