audiology final exam

evolution of audiology- WW2

-lack of hearing protection = noise induced hearing loss
-VA hospitals

otology and speech pathology formed

military-based aural rehabilitation centers b/c of influx of service personnel reentering civilian life

dr raymond carhart

"father of audiology"
-was an SLP
-otologist active in the establishment
of the military aural rehabilitation
programs

licensure

the credential required for the practice of audiology in the U.S.
- consumer protection

certification

not a legal requirement- ASHA required to hold CCC

specialty areas of audiology

medical, educational, pediatric, industrial

decibel

-involves a ratio
-uses a logarithm
-nonlinear (cannot be simply added/subtracted)
-must be expressed in terms of reference points
-relative- changes w/ reference

impedance

"opposition"
the opposition a medium offers to the transmission of acoustic energy
(as the density of an object in the path of
acoustic energy increases, the impedance
increases)

impedance matching

size difference between the TM and oval window, along w/ the leverage action created by the ossicles comprise what is known as-

interference

when more than one tone is introduced, there are interactions among sound waves-
can result in reinforcement or cancelation of waves

psychoacoustics

the study of the relationship between physical stimuli and the psychological responses they cause

pitch

a term used to describe the subjective impressions
of the “highness” or “lowness” of a sound

frequency and intensity

the physical value

pitch and loudness

the perceptual value

loudness

a subjective experience for intensity

dB SPL

measuring sound levels in environment

dB HL

measuring softest sound at specific frequency

dB SL

threshold of given individual (threshold 10, sound 60, dB SL=50)
(softest sound a specific person is capable of hearing)

outer ear structures

the part we see on the sides of our heads (pinna),
the ear canal, and
the eardrum (tympanic membrane)

pinna/auricle function

– gathers sound waves from the
environment
– funnels sound into the
external ear canal
– enhances delivery of high
frequency sounds relative to
low frequency sounds
– aids localization

ear canal function

entryway for sounds

tympanic membrane

the membrane vibrates with the force of the sound wave strike and transmits the vibrations further into bones of the inner ear- sound intake

eustachian tube

equalize pressure in middle ear to outside world
-maximize sound transmission

mastoid bone

during bone conduction hearing tests, the BC
vibrator is placed on-

malleus

middle ear ossicle embedded in fibrous portion of TM

stapes

smallest bone in middle ear

stapedius muscle

middle ear muscle stiffens the membrane in the oval window when it contracts in response to loud sounds

inner ear function

1. To transduce the mechanical energy delivered from the
middle ear into a form of energy that can be interpreted
by the brain
2. Reports information regarding the body’s position and
movement in a bioelectric code

3 fluid containing channels

scala vestibuli, scala media, scala tympani (inner ear)

outer hair cells

basilar membrane supports inner-

tectorial membrane

stereocilia on tips of outer hair cells are embedded in

external auditory canal

made of cartilage

2 ME muscles

stapedius muscle
tensor tympani muscle

ear infection cause hearing loss-

-this is due to inflammation and fluid buildup in the area behind the eardrum

two portions of inner ear

vestibular- equilibrium
cochlear- hearing

equilibrium

balance depends on inputs from the vestibular, visual,
and proprioceptive systems
– these inputs are gathered into the cerebellum where
a response is generated

cochlea organized

a long coiled tube, with three channels divided by two thin membranes

spiral ligament

supports the scala media

decussations

crossover points within the brain that unite symmetrical
portions

ipsilateral

on the same side

contralateral

on the opposite side

bilateral

having or relating to two sides; affecting both sides.

central auditory nervous system

includes nerve fibers and nuclei (cell bodies) of the brain stem, midbrain, and cortex.

sensorineural hearing loss

hearing loss that occurs when there is damage to the inner ear

sensory vs. neural hearing loss

sensory- hearing impairment due to dysfunction of cochlea
neural- dysfunction of cochlear nerve

trapezoid body

first decussation point of the auditory system

3 types of hearing loss

conductive
sensorineural
mixed

mixed HL example

an example would be if you have a hearing loss because you work around loud noises and you have fluid in your middle ear

conductive HL example

an example might be if your child put a pebble in his ear when playing outside

sensorineural HL example

-occurs when the inner ear or the actual hearing nerve itself becomes damaged
-your eardrum may not vibrate when you hear sound.

scale of impairment

moderately severe-56 to 70
severe-71 to 90
profound-91+

configuration

what shape

250-8000 Hz

frequencies routinely tested by air conduction in a routine hearing test

500-4000 Hz

routinely tested by bone conduction in a routine hearing test

three-frequency PTA

average of 500, 1000, and 2000 Hz

air-bone gap

the difference between air conduction thresholds and bone-conduction thresholds- 15 dB or more
suggests middle/outer ear dysfunction

cross hearing

the reception of a sound signal during a hearing
test (either by air conduction or bone conduction)
by the non-test ear.

masking

introducing a noise into the non-test ear to
raise its threshold so that it cannot respond to
a signal presented in the test ear

speech recognition threshold (SRT)

the SRT is the lowest hearing level at which speech can
barely be understood at least 50% of the time
• used as a check of the reliability of pure tone
thresholds

speech detection threshold (SDT)

also referred to as the speech-awareness threshold (SAT)
the lowest level, in decibels, at which a subject
can barely detect the presence of speech and identify it as
speech
- does not imply that speech is understood, just
detected

word recognition score (WRS)

purpose: to obtain a percentage measure that quantifies
how clearly speech is heard

interpreting WRS

• 90 to 100%: Normal limits
• 70 to 90%: Slight difficulty; similar to listening over a telephone
• 60 to 75%: Moderate difficulty
• 50 to 60%: Poor recognition; patient would experience marked
difficulty in following conversation
•

signal-to-noise ratio

reflects the relative intensity of the signal (speech)
and the competing noise
-not an actual ratio - but an expressed
difference in intensities

monitored live voice

– 3-5 seconds should be allowed between word
presentation to permit the patient to respond
– a carrier phrase should precede (e.g. “say the word”)
– as with SRT tests, control of the signal level is
paramount
– the last word of the carrier phrase (not the test word)
is the peak word

recorded materials

standardized spoken language for speech recognition testing

why we perform speech audiometry

– to measure the degree of hearing loss for speech
– to assess the ability to recognize and discriminate the
sounds of speech
– to determine the dynamic range for speech sounds
– to find the patient’s most comfortable listening level
– to find the patient’s threshold of discomfort or
uncomfortable listening level

what should SRT match

the patient’s PTA (for a given ear)

dynamic range

the difference between a threshold measure and the
UCL for the same signal

sensorineural HL is

a type of hearing loss associated w/ a reduced dynamic range

purpose of tympanograms

•to see if the ear canal is occluded
•to see if the tympanic membrane (eardrum) is
intact
•to see if the middle ear structures (TM and
ossicles) are functioning properly

ear canal volume

a measurement of air volume in the ear canal between the tympanometer probe tip and the tympanic membrane

middle ear pressure

the pressure level at which the peak of
the tympanogram is at its highest
- occurs when one puts the same amount
of pressure in the ear canal that is behind
the eardrum in the middle ear

middle ear pressure aka

peak pressure aka point of maximum compliance

type A tympanogram

•normal ear canal volume
•normal pressure of peak compliance
•normal peak compliance

type As tympanogram

•normal ear canal volume
•normal pressure of peak compliance
•lower than normal peak compliance

type Ad tympanogram

•normal ear canal volume
•normal pressure of peak compliance
•higher than normal peak compliance

type C tympanogram

•normal ear canal volume
•abnormal pressure of peak compliance
(in the negative range)
•normal peak compliance

type B tympanogram

•normal ear canal volume
•no pressure of peak compliance is
recorded (b/c there is no movement)
•no peak compliance is recorded

type B, large volume tympanogram

•LARGE (abnormal) ear canal volume
(usually ABOVE 2.0 ml – but more likely
it will be much higher than that)
•no pressure of peak compliance is
recorded (b/c there is no movement)
•no peak compliance is recorded

spontaneous OAE

occur when a cochlea produces sounds in the absence of
external stimulation

transient-evoked OAE

• stimulus: broadband clicks or tone pips
• present in individuals with hearing thresholds < 40 deciBel HL

distortion-product OAE

stimulus: two primary tones varying in frequency by
several hundred hertz (F1 and F2)
• a variety of primary-tone frequencies are used stimulating different areas of the cochlea
• present in individuals with hearing thresholds < 40 to 50
deciBel HL

clinical application of OAEs

- identification of hearing loss
- monitoring for possible ototoxicity
- differentiation of organic versus non-organic hearing loss

presence of OAE

- can test w/ ---
normal hearing or potentially mild sensorineural hearing loss

absence of OAE

cannot test w/ ---
could be because of blockage, dysfunction of middle ear, or of outer hair cells

values of OAEs

- brief test time
- relatively simple technique
- objective
- independent of age
- ear specific
- frequency specific

limitations of OAEs

- ambient acoustic noise in the test setting
- physiological noise produced by the patient
- technical factors (e.g., insertion of the probe
tip in the ear canal)
- cerumen, vernix, or debris in the ear canal
- status of the middle ear system

auditory evoked potentials

AEP
designed to analyze the electric activity
of the brain when stimulated by acoustic stimuli

ABR

auditory brain-stem response

AEP clinically

allow a determination of whether poor hearing results from inner ear, nerve to the ear, or brain problems

AEPs listed

ABR- auditory brain-stem response
AMLR- auditory middle latency response
ALR- auditory late response

AEP- patient remain calm

muscle movement could look like an auditory response- too much activity

high-risk registry

an economical tool for early identification of hearing loss
-only caught 50% of newborns with hearing loss

JCIH

joint committee on infant hearing

JCIH recommends

best outcomes are realized when children are identified by 1 month of age- fit with hearing technology by 3 months of age and begin intervention by 6 months of age. (1-3-6)

APGAR test

used for infants HS
A- appearance
P- pulse
G- grimace
A- activity
R- respiration

pediatric audiologist familiar with milestones

not only for speech and language, but also for motor, cognition, etc.

visual reinforcement audiometry

6 months to 2 years
reward children’s auditory responses with visual
stimuli has led to the use of-

conditioned play audiometry

2 to 5 years
children who have no problems other than hearing loss can often be taught to respond to pure tones, usually via play
audiometry.

congenital/prenatal

occurring before birth