Glossary of Terms

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Acoustic Reflex – The contraction of one or more muscles of the middle ear in response to the presentation of a loud stimulus.

Acquired – Obtained or developed subsequent to birth (post-natally).

Acuity – The sharpness, clearness, or distinctness with which one is able to hear a sound.

Adenoids – A mass of lymph (tonsil’‘like) tissue surrounding the Eustachian tubes in the back of the throat and/or nasopharynx.

Air Conduction – A term denoting the movement of the sound waves through the air. For example, a hearing test conducted with ear phones is called an “air conduction” hearing test inasmuch as the sound waves move through the external ear canal striking the ear drum.

Ambient Noise – Any noise exclusive of an intentional signal in a test room environment. The noise may come from outside or from within the room.

Atresia – The absence or closure of the external or middle ear.

Attenuate – The reduction in intensity of tone or speech sounds.

Attenuator – The dial on an audiometer that increases and decreases the loudness of a signal.

Audiogram – A record of hearing levels measured at several different frequencies. A graphic picture of hearing at a particular point in time.

Audiologist – An individual who is professionally trained to administer and interpret hearing evaluations.

Audiology – The science of hearing; particularly the hearing function. It is a diagnostic profession concerned with the determination of the type of hearing loss being manifested by a particular individual.

Audiometer – Electronic equipment used to screen or assess hearing acuity.

Audiometry – Refers to the technique of measuring hearing. Measurements may be made of the auditory response to any of several auditory stimuli, but fixed’‘frequency pure tones and speech sounds are most commonly used.

Auditory – Pertaining to the ear or the organs of hearing.

Auditory Brainstem Response (ABR) – An objective technique to evaluate hearing which involves placing electrodes on the head and recording brain wave activity from the brainstem as sounds are presented.

Auditory Nerve – Sensory nerve (VIII cranial nerve) composed of fibers which arise from the cochlea and vestibular apparatus terminating in the brain stem.

Auditory Neuropathy Auditory Dys-Synchrony (AN AD) – A disorder in the efficient transmission of sound somewhere from the inner hair cells of the cochlea to the brainstem.

Automated Auditory Brainstem Response (AABR) – Objective technique used to screen newborns.

Bone Conduction – The process by which sound is conducted to the inner ear through the cranial bones.

Brainstem – The bundle of nerve fibers which is located below the cerebrum and above the spinal cord.

Central Auditory Nervous System – That part of the auditory mechanism just past the hair cells in the cochlea up to and including the auditory cortex.

Central Auditory Processing Disorder (APD) – A child’s inability to efficiently use what they hear in spite of normal hearing acuity. APD testing is administered in a sound room by an audiologist. Normative data is available for children six years of age.

Cholesteatoma – A pearl-like growth that may develop in the middle ear space as the result of debris entering the middle ear through a perforation.

Cochlea – The snail shaped fluid filled cavity which serves as the receptor for hearing.

Cochlear Implant – A surgically implanted device designed for individuals with severe-to-profound hearing loss who do not receive adequate benefit from hearing aids.

Conditioned Play Audiometry (CPA) – Technique used to screen or evaluate hearing which includes conditioning the child to perform a task (e.g., drop a block into a bucket) in response to a sound.

Conductive Hearing Loss – An interference with the movement of the sound wave as it passes through the external and middle ear on its way to the inner ear. A conductive hearing loss usually can be corrected and/or improved via medical treatment.

Congenital – Existing at birth. Could be a hereditary condition.

Decibel (DB) – A unit of sound intensity (loudness).

Discrimination Score – A percentage score which reflects a persons ability to understand (clearly hear) speech. (See word recognition score).

E.N.T. – Refers to a physician whose practice is confined to the treatment of disorders of the ear, nose, and throat. Otorhinolaryngologist is synonymous with E.N.T.

Ear Drum – Also known as the tympanic membrane. A thin, translucent membrane which moves in response to sound waves traveling through the external auditory canal.

Educationally Significant Hearing Loss – Audiologically it is: a) pure tone average (500-2000 Hz) of at least 20 dB in the better ear, or b) an average high frequency loss of at least 35 dB in the better ear for two or more of the following frequencies, 2000, 4000, or 6000 Hz, or c) a permanent unilateral hearing loss of 45 dB or greater.

Endolymph – The fluid found within the scala media.

Environmental Sound – Sounds that surround us in our everyday life. See ambient noise.

Eustachian Tube – A tube’‘like passageway which extends from the middle ear cavity to the back of the throat (nasopharynx). There is one Eustachian tube for each ear. Adenoidal tissue usually surrounds the Eustachian tube openings at the back of the throat. Abnormal Eustachian function is evidenced by negative middle ear pressure.

External Auditory Canal – A cylindrical passageway which funnels sound waves from the pinna to the eardrum.

Frequency – The number of vibrations per second; written as Hz (Hertz).

Gradient – The pressure interval of a tympanogram corresponding to a 50% reduction in the compliance. (See tympanometric width).

Hair Cells – Microscopic cells in the cochlea that begins the transmission of sound from the inner ear to the auditory nerve. If damaged or absent, sensorineural hearing loss results.

Heredity – The passing of genetic qualities through ancestry.

Hertz (Hz) – The international term for cycles per second. See frequency.

Identification Audiometry – Refers to the application of hearing screening and testing procedures to persons for the purpose of identifying those individuals with hearing acuity less than generally defined as within normal limits.

Immittance Measures – An objective technique to assess the integrity and function of the middle ear system.

Incus – The second or middle bone of the ossicular chain, which is located between the malleus and the stapes.

Internal Auditory Canal – A tube’‘like passageway in the temporal bone which houses the auditory nerve.

Interrupter Switch – The tone presentation control on an audiometer.

LOHL – Late Onset Hearing Loss (LOHL) is when a child develops a hearing loss sometime after birth but before entering kindergarten.

Malleus – The first bone of the ossicular chain which is attached to the ear drum and to the incus. It is the largest one in the ossicular chain.

Mastoid – A bone composed of a series of air filled cells located behind the middle ear cavity.

Middle Ear Cavity – A small air filled space which houses the ossicular chain and from whence the Eustachian tube originates.

Middle Ear Compliance – Relates to the mobility of the middle ear system.

Middle Ear Pressure – Relates to the air pressure within the middle ear cavity (either positive or negative daPa). The point of maximum compliance.

Mixed Hearing Loss – A hearing loss which has both a conductive and sensorineural component.

Noise – Any unwanted sound.

Noise Induced Hearing Loss – A term referring to the slowly progressive sensorineural hearing loss that results from exposure to intermittent and/or continuous loud noise.

Non-Organic Hearing Loss – A loss of hearing for which there is no known organic basis.

Organ Of Corti – The highly sensitive receptor of hearing which contains the hair cells and the auditory nerve endings. It is housed within the cochlea.

Ossicles Or Ossicular Chain – The bridge of three small bones (malleus, incus, and stapes) across the middle ear cavity.

Otitis Media – Inflammation of the middle ear. acute: An inflammation of the middle ear lasting for a short period of time. chronic: A long’‘term or continuing inflammation of the middle ear.

Otoacoustic Emission (OAE) – An objective technique to screen or assess hearing. Emissions are sounds generated within the cochlea that can be measured in the ear canal.

Otologist – A physician whose practice is confined to the medical treatment of ear disorders.

Otology – The branch of medicine that is concerned with the ear.

Oval Window – A small opening, covered by a thin membrane, in the cochlea which accommodates the footplate of the stapes.

Perilymph – The fluid found in the scala, vestibuli and scala tympani.

Peripheral Auditory Nervous System – The part of the auditory mechanism up to and including the hair cells in the cochlea.

Physical Volume – The amount of space (in ml or cc) between the probe tip and wherever the air cannot get any farther (usually the tympanic membrane). Measured by applying +200 daPa.

Pinna – The most visible portion of the external ear.

Pure Tone – A single frequency sound without accompanying overtones or other sounds.

Pure Tone Average (PTA) – Computed by averaging the thresholds in each ear at 500, 1000, and 2000 Hz or in the case of a high frequency hearing loss, 500 and 1000 Hz may be used.

Reliability – Repeatability.

Responsible Person – Individual who is assigned to ensure that timely follow-­up occurs between identification audiometry and the initiation of appropriate services. This person must have a thorough understanding of the services available within a community and must be willing to make necessary phone calls.

Roster – Form used to record children’s names and their screening results.

Round Window – A small opening in the cochlea, covered by a thin membrane, located below the oval window.

Rubella – German measles.

Scala Media – The middle fluid filled tunnel of the cochlea which houses the organ of Corti.

Scala Tympani – The outer fluid filled tunnel of the cochlea which communicates with the middle ear via the round window.

Scala Vestibuli – The fluid filled tunnel of the cochlea which communicates with the middle ear via the oval window.

Sensitivity – Ability of a test or measure to identify individuals with the target disorder.

Word Recognition Score – A percentage score reflecting an individual’s ability to discriminate single syllable words from a phonetically balanced word list. See discrimination score.