3030 Audiology: Threshold Detection, Audiometry, and Auditory Anatomy

Comprehensive vocabulary flashcards covering audiological evaluation methods, hearing threshold definitions, psychophysical testing techniques, degrees and configurations of hearing loss, and auditory system anatomy and physiology.

Threshold of Hearing

The minimum audible sound intensity needed for an individual to just detect the presence of a stimulus, audible 50% of the time.

Human Auditory Frequency Range

The full span of human hearing, spanning from $20\text{ to }20{,}000\text{ Hz}$, with clinical testing typically evaluating the range between $250\text{ to }8000\text{ Hz}$.

Minimum Audible Field (MAF)

Hearing threshold measured as a function of frequency using loudspeakers in a free-field listening environment.

Minimum Audible Pressure (MAP)

Hearing threshold measured as a function of frequency using headphones (e.g., MAP-TDH) or foam insert earphones placed in the ear canal (MAP-inserts).

Auditory Sensitivity and Dynamic Range Curves

A plot depicting auditory thresholds across frequency for different listening transducers (MAP-TDH, MAP-Inserts, MAP-Sennheiser, and MAF) in relation to the upper thresholds of auditory discomfort and pain.

Method of Limits

The most common clinical psychophysical method for threshold testing; it starts at $1000\text{ Hz}$ and $40\text{ dB HL}$, decreases by $10\text{ dB}$ steps until no response occurs, increases in $5\text{ dB}$ steps until heard, and brackets to find two responses at one level.

Hit

In threshold testing, a trial outcome where the subject correctly responds when a tone stimulus is present.

Miss

In threshold testing, a trial outcome where the subject fails to respond even though a tone stimulus was presented.

False Positive

In threshold testing, a trial outcome where the subject responds when no tone stimulus was presented.

Correct Rejection

In threshold testing, a trial outcome where the subject provides no response when no tone stimulus is present.

Ascending Run

A testing approach that starts below threshold and raises intensity in steps, resulting in higher thresholds; used by the Veterans Affairs (VA) and useful for evaluating malingering.

Descending Run

The standard audiometric methodology that starts at an audible intensity level and drops down in intensity, typically yielding lower thresholds.

Békésy Audiometry

A method of adjustment where the client controls a push-button (holding it down as long as the tone is audible and releasing when inaudible); the threshold is determined as the halfway point between peaks on the tracing.

Method of Constant Stimuli

An experimental technique not used clinically where a constant number of stimuli are presented at randomized intensities per frequency, defining threshold as the intensity with a 50% hit rate.

Air Conduction Audiometry

A procedure using headphones, insert earphones, or speakers to determine whether hearing loss exists and specify its degree, though it cannot independently determine the etiology.

Bone Conduction (BC)

The direct stimulation of the cochlea in the inner ear via mechanical vibration of the skull through a bone vibrator, representing the patient's best possible hearing sensitivity.

Air-Bone Gap (ABG)

The difference between air conduction thresholds and bone conduction thresholds, examined to identify the specific type and etiology of hearing loss.

Audiogram of Familiar Sounds

A clinical reference graph displaying everyday environmental noises and speech sounds plotted by their frequency ($\text{Hz}$) and intensity ($\text{dB HL}$) to contextualize hearing loss.

Normal Hearing (Adult vs. School-Aged Child)

Audiometric thresholds measuring $0\text{ to }20\text{ dB HL}$ for adults, and $0\text{ to }15\text{ dB HL}$ for children in school.

Slight Hearing Loss

A degree of hearing loss in school-aged children defined by thresholds between $16\text{ to }25\text{ dB HL}$.

Mild Hearing Loss

A degree of hearing loss characterized by thresholds ranging from $21\text{ to }40\text{ dB HL}$.

Moderate Hearing Loss

A degree of hearing loss characterized by thresholds ranging from $41\text{ to }55\text{ dB HL}$.

Moderately Severe Hearing Loss

A degree of hearing loss characterized by thresholds ranging from $56\text{ to }70\text{ dB HL}$.

Severe Hearing Loss

A degree of hearing loss characterized by thresholds ranging from $71\text{ to }90\text{ dB HL}$.

Profound Hearing Loss

A degree of hearing loss characterized by thresholds at or exceeding $91+\text{ dB HL}$.

Flat Configuration

An audiometric pattern where hearing threshold levels start and stop within the same intensity range across all frequencies.

Sloping Configuration

An audiometric configuration where hearing is better in the lower frequencies and worsens toward the higher frequencies.

Rising Configuration

An audiometric configuration where hearing thresholds are worse in the lower frequencies and improve toward higher frequencies.

Cookie Bite Configuration

An audiometric configuration where hearing thresholds are normal at both the low and high frequency ends, with the loss restricted to the mid-pitches only.

Peripheral Auditory System

The anatomic division comprising the external ear, middle ear, inner ear (cochlea and vestibular system), and the auditory nerve (VIIIth cranial nerve).

Central Auditory System

The neural auditory structures comprising the auditory nerve (VIIIth cranial nerve) and brain structures: cochlear nucleus, superior olivary complex, lateral lemniscus, inferior colliculus, medial geniculate body, and cortex.

Middle Ear Impedance Matching

The physiological mechanism of the middle ear that enables sound conduction into the inner ear with minimal loss by matching mechanical impedance from air to fluid.

Inner Ear Transduction

The physiological conversion of acoustic sound input from mechanical motion into neural electrochemical output within the cochlea.