Hearing Threshold Level
Minimal hearing level at which an individual responds to a pure-tone audiometric test at least 50% of the time.

Hertz (Hz)
The unit of measurement that specifies the frequency or pitch of a sound wave.

High Risk
Children who have one or more of the risk factors known to impact hearing.

Immitance Instrument
The instrument used to measure acoustic immitance. Previously known as an immitance bridge or an immitance audiometer.

Immitance testing
Formerly known as impedance or tympanometry testing. An objective method of testing the integrity and function of the middle ear system.

Impedance Testing
See immitance testing.

Incus (anvil)
The middle bone of the ossicular chain in the middle ear; resembles an anvil.

Inner Ear
Made up of the cochlea, semi circular canals, and vestibules. These structures are responsible for the sense of hearing and balance.

Intensity
The loudness of a sound that is measured in decibels (dB).

In Utero
In the uterus or before birth.

Labyrinth
Organ of balance located in the inner ear. Consists of three semicircular canals and the vestibule, or bony cavity of the inner ear.

Loudness
The subjective judgment of the intensity of a sound.

Mastoid
The hard bony area of the temporal bone just behind the auricle that is part of the middle ear.

Middle Ear
Portion of the ear that is an air-filled cavity between the outer and inner ear. Includes the tympanic membrane, the ossicles (bones), the mastoid and the opening to the Eustachian tube.

Mixed Hearing Loss
A combination of conductive and sensorineural hearing loss that involves both the middle and inner ear. The conductive hearing loss may be medically treated but the sensorineural hearing loss is usually permanent.

Myringotomy
Surgical opening of the eardrum with or without insertion of a ventilating tube.

Noise
Any sound that is unwanted, undesired, or that interferes with one’s hearing.

Noise-Induced Hearing Loss (NIHL)
Hearing loss (either temporary or permanent) that is caused by either a single exposure to a very loud sound or by repeated exposure to sounds over 90dB over an extended period of time. NIHL damages the sensitive structures of the inner ear.

Objective Screening
Consists of "hands on" examination or testing that produces measurable results. An example of objective screening is the OAE.

Organ of Corti
Organ of hearing in the inner ear located in the cochlea. Contains thousands of hair cells that change mechanical energy into neural energy that is then transmitted via the eighth nerve to the brain.

Ossicles
Three small bones in the middle ear cavity: malleus (hammer), incus (anvil), and stapes (stirrup); their main purpose is to deliver sound vibrations from the tympanic membrane to the cochlea in the inner ear.

Otitis Media
Inflammation or infection of the middle ear or eardrum that is the most common cause of conductive hearing loss in children.

Otoacoustic Emissions (OAE) Testing
A test that evaluates hearing in infants and young children by analyzing the brain’s responses to sound. When the cochlea is stimulated by audible sound the cochlear hair cells start to vibrate, which in turn produces inaudible sounds (otoacoustic emissions) that echo back into the middle ear and the ear canal.

Otolaryngologist
Physician or surgeon who specializes in the ears, nose, throat, and head and neck. Sometimes referred to as an Ear, Nose, and Throat (ENT) Doctor.

Otologist
Physician or surgeon who specializes in diseases of the ear.

Otosclerosis
A degenerative condition, rare in school-age children, in which abnormal bone growth fixates the middle ear bones and impedes transmission of sound to the inner ear.

Otoscope
Instrument to examine the ear canal and eardrum.

Ototoxic
Having a detrimental effect on either the auditory nerve or the organs of hearing.

Ototoxic Drugs
Drugs that in some individuals can damage the hearing and balance organs located in the inner ear.

Outer Ear
The portion of the ear from the pinna (auricle) through the external auditory canal to the eardrum (tympanic membrane); sound waves are collected by the pinna, channeled into the external auditory canal, and are transformed into mechanical energy at the tympanic membrane.

Pinna
Part of outer ear that gathers sound waves from the environment; also known as the auricle.

Pitch
The psychoacoustical correlate of frequency. Sounds can be ordered on a scale from low to high pitch.

Play Audiometry
Special technique used to screen hearing of young children and/or developmentally delayed individuals.

Postnatal
Of or relating to an infant immediately after birth.

Preauricular Sinus
A tiny pit in the skin of the helical root (the outer rim of the ear is called the 'helix'; the area where the helix is attached to the face is known as the 'helical root'). This pit (or sinus) is skin-lined and is typically less than one inch deep. These pits can become infected; an infected pit usually presents as a soft or hard swelling at the helical root. Preauricular sinuses are also significant because they can be an indicator of other ear problems.

Pressure Equalizing Tubes (PE Tubes)
See ventilation tubes.

Progressive
Increasing in extent or severity.

Pure Tone
A tone of a single frequency produced by an audiometer. A pure tone contains no harmonics or overtones.

Pure-Tone Testing
A method of hearing screening utilizing pure tones of various frequencies and intensities.

Residual Hearing
The amount of hearing available in a person with a hearing loss.

Screening Audiometry
Screening procedure that utilizes an audiometer to identify individuals in need of further hearing evaluation. Also called Sweep Screening.

Sensorineural Hearing Loss
Type of hearing loss due to pathology in the cochlea in the inner ear and/or pathology of the 8th auditory nerve (the nerve of hearing). This type of hearing loss is usually irreversible, but the use of hearing aids or cochlear implants can help children hear and develop speech and language.

Skin Tags
A growth of skin tissue often seen near the ears or elsewhere on the face or neck that is usually small, soft, and skin-colored. Can be attached by a narrow piece of tissue or can appear as a bump on the skin. Usually cause no discomfort or other symptoms, but can get irritated by clothing rubbing against them. In rare cases, children who have a skin tag(s) can also have a hearing problem.

Stapedius muscle
One of the small muscles attached to the stapes in the middle ear. Contraction of this muscle in response to a loud sound is an important part of immitance testing.

Stapes (Stirrup)
The third and smallest bone of the ossicular chain in the middle ear; resembles a stirrup.

Subjective Screening
Consists of information obtained verbally or in writing in response to questions. When performing a subjective hearing screening, these questions would be related to a family history of childhood hearing disability or loss, delay of language acquisition or history of such delay, and a history of repeated otitis media. The child, parent, or guardian must be asked if there are concerns about the child's hearing.

Threshold
See hearing threshold.

Tinnitus
Perceived ringing or roaring in the ears usually associated with sensorineural hearing loss.

Toxoplasmosis
Infection caused by the parasite toxoplasma gondii that can lead to hearing loss.

Tubes
See Ventilation Tubes.

Tympanic Membrane
Also known as the eardrum. A thin membrane between the external auditory canal and the middle ear cavity that vibrates in response to sound waves; the vibrations are then transferred to the ossicular chain of bones in the middle ear.

Tympanogram
The visual representation (results) of tympanometry.

Tympanometry
An instrument that measures the movement of the tympanic membrane and middle ear system under varying air pressures; see immitance testing.

Tympanostomy Mryingotomy Tube
Small plastic tube placed through the tympanic membrane to allow middle ear ventilation.

Types of Hearing Loss
See Conductive, Sensorineural, Mixed, Binaural/Bilateral, and Unilateral.

Unilateral Hearing Loss
A mild to profound hearing loss in one ear.

Ventilation Tubes
Small plastic or metal tubes inserted through the eardrum to drain fluid from the middle ear cavity and to equalize air pressure in the middle ear; also called PE tubes (pressure equalizing tubes).

Vestibular System
Located in the inner ear; responsible for maintaining balance, posture, and the body’s orientation in space.

Visual Reinforcement Audiometry (VRA)
Subjective method for testing hearing in children between 6 months and 2 years of age. The child is trained to look toward a sound source and is rewarded for giving a correct response to the sound.