Chapter 3 – The Human Ear, Hearing Loss, and Pure-Tone Hearing Tests

Vocabulary flashcards covering key anatomical parts, testing concepts, types of hearing loss, and clinical terms from Chapter 3’s discussion of the ear, hearing loss, and pure-tone testing.

Anatomy

The study of the structure of the body; in audiology it refers to the physical parts of the auditory system.

Physiology

The study of how the body functions; in audiology it describes how the ear and auditory pathways operate.

Outer Ear

Shell-like pinna plus external auditory canal ending at the tympanic membrane; part of the conductive mechanism.

Tympanic Membrane

The eardrum; vibrates in response to sound, converting acoustical to mechanical energy.

Middle Ear

Air-filled space containing the ossicular chain (malleus, incus, stapes) that transmits mechanical vibrations.

Stapes

Third and smallest ossicle; its footplate moves in the oval window of the cochlea.

Inner Ear

Fluid-filled cochlea and vestibular organs; converts mechanical/hydraulic energy to electrochemical signals.

Cochlea

Spiral inner-ear structure responsible for hearing; houses sensory hair cells.

Auditory Nerve

Cranial nerve VIII; carries electrochemical impulses from cochlea to brain stem.

Conductive Mechanism

Combined outer and middle ear portions that conduct sound to the inner ear.

Sensory/Neural Mechanism

Inner ear (sensory) plus auditory nerve and pathways (neural).

Air Conduction (AC)

Pathway of sound through outer, middle, and inner ear; tested with earphones.

Bone Conduction (BC)

Direct stimulation of the cochlea by vibrating the skull; bypasses outer & middle ears.

Conductive Hearing Loss

Hearing impairment caused by obstruction or dysfunction of outer or middle ear; BC normal, AC impaired.

Sensory/Neural Hearing Loss

Loss due to damage in inner ear or auditory nerve; AC and BC equally impaired, no air-bone gap.

Mixed Hearing Loss

Combination of conductive and sensory/neural components; BC impaired, AC further impaired creating an air-bone gap.

Central Hearing Loss

Deficit originating in auditory centers of the brain, often affecting processing rather than audibility.

Nonorganic Hearing Loss

Reported hearing loss with no or insufficient organic pathology; may involve malingering or psychogenic factors.

Pure-Tone Audiometry

Electronic test measuring hearing thresholds for discrete frequencies via air and bone conduction.

Audiometer

Instrument that generates calibrated pure tones (and masking noise) for hearing tests.

Threshold of Hearing

Lowest intensity (dB HL) at which a tone is heard 50% of the time.

Air-Bone Gap (ABG)

Difference between AC and BC thresholds; size indicates conductive component.

Masking

Presentation of noise to nontest ear to prevent it from detecting test signals.

Insert Earphones

Foam-tipped receivers inserted into ear canal; provide high interaural attenuation and reduce ambient noise.

Supra-aural Earphones

Traditional ear-cup headphones that rest on pinna; lower interaural attenuation than inserts.

Bone-Conduction Vibrator

Oscillator that delivers vibratory stimuli to mastoid or forehead for BC testing.

Occlusion Effect

Artificial improvement in low-frequency BC thresholds when ear canal is covered or plugged.

Tuning Fork Test

Simple acoustic test using vibrating metal fork to assess type of hearing loss.

Rinne Test

Compares AC vs BC of same ear; positive = AC louder (normal/SN), negative = BC louder (conductive).

Weber Test

Midline BC test of lateralization; tone localizes to poorer ear in conductive loss, better ear in SN loss.

Audiogram

Graph displaying hearing thresholds (dB HL) across frequencies for each ear.

Pure-Tone Average (PTA)

Average threshold at 500, 1000, 2000 Hz (or lowest two) used to estimate speech threshold and degree of loss.

Variable PTA (VPTA)

Average of the three worst thresholds at 500, 1000, 2000, 4000 Hz; gauges communication impact.

Interaural Attenuation

Reduction in sound energy as it crosses from test ear to nontest ear; higher for inserts than supra-aural phones.

Cross Hearing

Perception of sound by the ear opposite the one being tested due to insufficient attenuation.

False Positive Response

Patient indicates hearing a tone when none was presented.

False Negative Response

Patient fails to respond to a tone that is audible to them.

Békésy Audiometry

Automatic loudness-tracking hearing test in which patient controls a hand switch.

Sound-Isolated Chamber

Acoustically treated booth used to keep ambient noise below permissible levels during testing.

Noise-Cancellation Headphones

Active devices that reduce ambient noise; can be worn over inserts for field testing without a booth.

Calibration

Process of ensuring audiometer outputs meet ANSI standards for frequency and intensity accuracy.

Decibel Hearing Level (dB HL)

Intensity scale referenced to average normal hearing thresholds; 0 dB HL ≈ normal sensitivity.