Aural Rehab: Chapter 1 Overview Audiologic Rehab Part 1

Front 1

ACOUSTICS

Back 1

Physical science that pertains to
sound and vibration

For some species the ability to detect sound in their environment
can be critical for survival.

For humans, acoustic energy aids us in our most unique and significant ability – SPEECH!

Front 2

The transmission of sound occurs as the result of

Back 2

occurs as the result of
the movement of air particles.

Front 3

Sound

Back 3

is a wave that can travel through gases, liquids, and solids.

When travelling through air, molecules bounce off one another, causing them to disperse uniformly in space.

This is difficult to understand because
we can’t SEE them moving through air..

Front 4

Label

Back 4

Front 5

3 parts of the ear (Label)External ear AKA The Auricle (Label)

Back 5

Front 6

visible part of the ear are:

Back 6

-the Pinna
-the External Ear Canal

Front 7

Function of Outer Ear

Back 7

Collect sound
Localization
Resonator
Protection
Self expression by decorative mutilation

Front 8

Anatomy of the External Ear

Back 8

Front 9

Pinna

Back 9

The visible portion
Helps localize sound sources
Directs sound into the ear
Each individual's pinna creates a distinctive imprint on the acoustic wave

Front 10

The net effect of the pinna and ear canal is that sounds in the

Back 10

is that sounds in the 2,000 to 4,000 Hz region are amplified by 10 to 15 dB

Front 11

the purpose of Cerumen/ear wax

Back 11

-Repel water
-Trap dust, sand particles, micro-organisms, and other debris
-Odor discourages insects
-Antibiotic, antiviral, antifungal properties
-Cleanse ear canal

Front 12

Middle Ear Anatomy (Label)

Back 12

Front 13

Function of the Tympanic Membrane is to

Back 13

is to transduce sound pressure into mechanical vibrations, eardrum must be flexible, move with tiny fluctuations in air pressure, and be coupled
directly to the ossicles

Front 14

Ossicular Chain (Label)

Back 14

three smallest bones in your body and they are attached to the tympanic membrane:
Malleus/Hammer
Incus/Anvil
Stapes/Stirrup

Front 15

Eustachian Tube and its Function in the Middle Ear Space (Label)

Back 15

The Middle Ear Space SHOULD be air filled

Front 16

What Causes Eustachian Tube Dysfunction?

Back 16

Swelling caused
from allergies and
colds

Physical malformations
like cleft palate

Nasal masses

Another structure pushing on the eustachian tube such as adenoids or even the soft palate in some cases

Front 17

Function of the Middle Ear

Back 17

Remember that sounds come into the middle ear traveling on a soundwave through the air, but leave the middle ear space on a wave traveling in fluid. We call this an impedance mismatch.

Front 18

Impedance

Back 18

defined as the sum of all energy that opposes the transmission of sound

Front 19

If the impedance of two media (air and water in this case) are unequal

Back 19

the sound will not easily be transmitted
from one to the other

Front 20

More energy is required
to produce a

Back 20

is required to produce a sound wave in the fluid chambers of the inner ear than in the air around us where the sound originates

Front 21

What is Impedance Mismatch?
99.9% of sound is actually REFLECTED due _______
bones in the middle ear overcome this problem by ________

Back 21

-is actually REFLECTED due to high impedance of fluid in the cochlea (that means that only 0.1% passes through which results in a 30dB sound reduction level)
-overcome this problem by increasing sound pressure (adding back 34db)

Front 22

How Does the Middle Ear Overcome Impedance Mismatch?

Back 22

the tympanic membrane is much larger than the footplate of the stapes! The area of the eardrum is 20 times larger than the footplate of the stapes.

This size difference improves sound transmission (increases volume) by focusing the vibratory area onto the smaller footplate. Like hitting a large hammer on a nail head.

The sound increase equates to an increase of approximately 25 dB.

Front 23

Transformer/Amplifier

Back 23

Area ratio
Thumbtack

Lever
crowbar

Front 24

There are two systems in the Inner Ear

Back 24

Cochlea and Vestibular System

Front 25

Cochlea

Back 25

-Latin word for snail shell, the cochlea is the organ of hearing
-spirals for about 2 3/4 turns around a bony column

Front 26

Vestibular System

Back 26

Organ of Balance

Front 27

cochlea is responsible for

Back 27

is responsible for converting sounds which enter the ear canal, from mechanical vibrations into electrical signals

Front 28

the cochlea have 3 canals (Label):

Back 28

Scala Vestibuli
Scala Tympani
Scala Media

Front 29

As the stapes footplate vibrates in the oval window, fluids

Back 29

fluids (called perilymph and endolymph) are disturbed and cause a deflection of the membranes in the cochlea

Front 30

Movement of these fluids (called perilymph and endolymph) moves the basilar membrane, then stimulates

Back 30

then stimulates tiny hair cells that ultimately transmit electrical signals to the brain

Front 31

The Cochlea’s Main Function

Back 31

Transduction

Front 32

stria vascularis

Back 32

is the blood supply to the organ, and maintains the metabolic processes and fluid balance within the cochlea

Without the stria vascularis and its maintenance the all important transduction process cannot occur

Front 33

Transduction

Back 33

is performed by specialized sensory cells
within the cochlea

The electrical signals, which code the sound's characteristics, are carried to the brain by the auditory nerve.

Front 34

Two chambers called the scala vestibuli and scala tympani are filled with a fluid called

Back 34

perilymph, the major ingredient is sodium, but potassium is also present

Front 35

The third chamber in this equation is called the

Back 35

cochlear duct or scala media
Triangular shaped and filled with endolymph. It’s main ingredient is potassium, and sodium is also present

Front 36

The side of the scala media contains the blood supply of the organ called the

Back 36

stria vascularis

Front 37

Cross Section of Cochlea (Label)

Back 37

Front 38

Organ of Corti (Label)

Back 38

Front 39

Endolymph

Back 39

-is charged at 80 millivolts while the hair cells are charged at -70 millivolts
-create the strongest voltage range in the body allowing sound signals to be transduced into electrical signals that are sent to the brain
-stria vascularis is responsible for maintaining this battery’s “charge"

Front 40

inner ear

Back 40

ear is a fluid filled cavity full of nerves called Hair Cells, Transmit sounds to the brain

Front 41

Outer Hair Cells

Back 41

Receive and Detect sounds

Front 42

Vibrations from the Ossicles create a

Back 42

create a “wave” in the inner ear fluid that stimulate the hair cells

Front 43

Outer Hair Cells Vs. Inner Hair Cells

Back 43

Outer hair cells (OHCs):
3 to 5 rows
12,000 cells
50-150 stereocilia per cell

Inner hair cells (IHCs):
1 or 2 rows
3,500 cells
50-70 sterocilia per cell

Front 44

While the Inner hair cells are likely stimulated by fluid movement, the Outer hair cells are

Back 44

motile

Front 45

Outer hair cells exhibit

Back 45

motility, expanding and contracting with the polarity of the cochlea

Front 46

The outer hair cells are responsible for

Back 46

are responsible for cochlear emissions also known as cochlear echoes. We call these OAEs

Front 47

Otoacoustic emissions (OAEs)

Back 47

are an incredibly useful tool we use to objectively confirm normal outer hair cell function

Front 48

Inner Hair Cells

Back 48

Cause the release of neurotransmitters and the initiation of action potentials in the neurons of the auditory nerve

Front 49

Action potential

Back 49

'firing‘ of a neuron

Front 50

Propagation

Back 50

is in one direction only down the length of the axon

Front 51

Most of the afferent neurons make contact with the

Back 51

make contact with the inner hair cells, and carry information from the cochlea to the higher auditory system

POSSIBLY all information about the input sound is
conveyed via the inner hair cells

Front 52

Outer Hair Cells

Back 52

-Have a major role in improving sensitivity to soft sounds
-Improve frequency resolution

Front 53

efferent neurons

Back 53

-most synapse directly with the outer hair cells
-carry information from the higher auditory system (brain) to the cochlea

Front 54

frequency resolution

Back 54

sharp tuning of the sound

Front 55

Afferent Neural Innervations (Label)

Back 55

Front 56

PURE TONE TESTING

Back 56

Air Conduction
Bone Conduction
Speech Testing

Front 57

Output Transducers

Back 57

Convert the signal from electrical to acoustical

Front 58

4 Different Types of Output Transducers

Back 58

Standard Headphones/Supra-aural
Insert Earphones
Bone vibrator
Speakers in Soundfield

Front 59

Air conduction testing

Back 59

sends the signal through all 3 parts of the ear, and is therefore affected by problems in the outer or middle ear.

Front 60

Bone conduction testing

Back 60

stimulates the nerve directly and therefore can be a more accurate picture of the patient’s hearing potential.

Front 61

In most cases we need to test BOTH air and bone and
compare our results in order to

Back 61

in order to locate the source of the problem
and determine the proper treatment pathway

Front 62

Speech Detection/Awareness Threshold (SDT/SAT)

Back 62

The lowest level at which the listener
can tell that “something” is there
(the signal just happens to be speech)

Front 63

Speech Recognition/Reception Threshold (SRT)

Back 63

The lowest level at which the listener
can actually “identify” what the
speech stimulus is (and can repeat it back to the tester)

Front 64

THE HEARING TEST(non-behavioral)

Back 64

TYMPANOGRAM

ACOUSTIC REFLEX TESTING
(ART)

OTOACOUTIC EMISSIONS
(OAEs)

Front 65

Physiological Tests

Back 65

Acoustic Immittance/Impedance measures
(Tympanogram & ARTs)

Otoacoustic emission (OAE) testing

Front 66

Acoustic Immittance/Impedance measures
(Tympanogram & ARTs)

Back 66

Tests the outer and middle ear spaces with implications for the inner ear, auditory nerve, and lower auditory brainstem

Front 67

Otoacoustic emission (OAE) testing

Back 67

Measures the function of the inner ear (dependent on normal outer and middle ear status.)

Front 68

Tympanometry

Back 68

Measures the efficiency of energy flow into the middle ear system as air pressure is varied in the external ear canal

Front 69

Tympanogram call tell us about the following:

Back 69

Ear Canal Volume
Static Admittance (height)
Peak Pressure

Front 70

REVIEW TYMPANOGRAM TYPES

Back 70

LOOK IN OLDER SLIDES

Front 71

OtoAcousticEmissions (OAE) (adults)

Back 71

Identification of functional hearing loss
Behaviorally Unresponsive Patients Identification of Auditory Neuropathy
Noise-induced cochlear damage

Front 72

Diagnosing Hearing Loss involves

Back 72

Severity

Configuration

Type

Front 73

TYPES OF HEARING LOSS

Back 73

Conductive Hearing Loss
(often temporary)

Sensorineural Hearing Loss
(usually permanent)

Mixed Hearing Loss

Front 74

Common Causes of Temporary Hearing Loss

Back 74

Infection in the middle ear called Otitis Media, which occurs frequently among infants and young children.

Calcification around the bones in the middle ear called otosclerosis.

Separation between bones called ossicular disruption or disarticulation.

Wax buildup or obstruction in the ear canal.

Front 75

Prelingual Hearing Loss

Back 75

Occurs PRIOR to normal speech and language development

Front 76

Postlingual hearing loss

Back 76

Occurs AFTER speech and language development

Front 77

The disabling consequences of hearing loss on speech and language development in patients with prelingual hearing loss can be

Back 77

can be more severe than in patients with postlingual hearing loss

-In either case, intervention should occur shortly after onset of the hearing impairment, unfortunately this is not always the case.

Front 78

Reasons for Delayed Intervention

Back 78

-Older adults who have developed hearing loss gradually may deny its existence and resist intervention even after diagnosis.

-Denial may also be the reason for delayed -intervention with an infant if a parent is unwilling to accept that a hearing impairment exists.

-Ideally onset, identification, and intervention should occur successively and in a timely manner.

Front 79

For infants and young children early identification
and intervention are

Back 79

are critical to maximize speech and language development

-Yoshigana-Itano and associates (1998) found that newborns diagnosed prior to 6 months of age who are treated appropriately can achieve higher language levels than children with delayed diagnoses.

Front 80

Although there are a variety of underlying causes for hearing loss, there are two major pathways for the treatment of hearing loss:

Back 80

1. Hearing loss that is medically treatable with medication or surgery.

2. Hearing loss that effects the nerve, is permanent in nature (not treatable with medication or surgery), and reduces the patient’s ability to communicate effectively.

Front 81

Medically Treatable Hearing Loss:
If the hearing loss is determined to be medically treatable, the patient is referred to

Back 81

the patient is referred to their primary care physician or ENT specialist for treatment and retested in order to
evaluate the outcome of the medical intervention

Front 82

Permanent Hearing Loss:
If the hearing loss is not medically treatable, the audiologist will

Back 82

the audiologist will alleviate the patient’s communication difficulties using aural habilitation or rehabilitation

Front 83

Aural Rehabilitation includes

Back 83

includes hearing aid fitting, counseling, educating, listening training, speechreading, and referral to speech-language pathology if appropriate

Front 84

The ability to hear plays a direct role in

Back 84

plays a direct role in the ability to perceive and produce speech

Front 85

The primary goal in assisting individuals with hearing impairment is to

Back 85

is to maximize the ability to hear and understand speech, and in the case of young children, to accurately produce speech with the help of a speech-language pathologist

Front 86

Many different kinds of Hearing Rehabilitation for Permanent Hearing Loss

Back 86

Hearing Aids
Rehabilitation Therapy
Assistive Listening Devices
Cochlear Implants
Surgically Implantable Devices