csd 2230 human communication disorders audiology the profession acoustics anatomy hearing loss...

CSD 2230HUMAN COMMUNICATION DISORDERS

Audiology The Profession Acoustics Anatomy Hearing Loss and Pathologies Assessment and Treatment

The Profession of Audiology

The discipline involved in:

The prevention, identification, and evaluation of hearing disorders

The selection and evaluation of amplification systems

The habilitation/rehabilitation of individuals with hearing loss

What Kinds of Audiologists are There?

Rehabilitative Audiologists

Educational Audiologists

Medical Audiologists

Industrial Audiologists

Audiologists in Private Practice

University-Based Audiologists

Why Are Audiologists Important??

Hearing loss interferes with communication…

AdultsConsequences

ChildrenConsequences

Video

The Hearing System

The Hearing System

Basic schematic diagram of the entire auditory system

The Outer Ear

Major Landmarks:

1. Pinna2. External Auditory

Meatus3. Tympanic Membrane

Function of the Outer Ear

1. Collect and funnel sound to the eardrum

2. Protection3. Resonance

The Middle EarMajor Landmarks:

1. Middle Ear Space

2. Eustachian Tube

3. Oval and Round Windows

4. Ossicles

Function of the Middle Ear

1. Amplifier and Transformer

2. Protection

The Inner Ear

Major Landmarks:

1. Bony Labyrinth2. Cochlea3. Auditory and

Vestibular Portions

4. Organ of Corti5. Hair Cells

Central Auditory Pathways

Types of Hearing Impairment

A loss of

sensitivity

Auditory nervous

system

pathology

Important Terms

Time of onset Congenital

Acquired Adventitious

Important Terms

Time Course• Acute Chronic Sudden Gradual Temporary Permanent Progressive Fluctuating

Important Terms

Number of Ears Involved

Unilateral Bilateral

Hearing Sensitivity Loss

§ “The ear is not as sensitive as normal in detecting sound”

Types:

Conductive Sensorineural Mixed

Conductive Hearing Loss

“Caused by an abnormal reduction or attenuation of sound as it travels from the outer ear to the cochlea”

Sensorineural Hearing Loss

“Caused by a failure in the cochlea to transduce the sound from the middle ear to neural impulses in the VIII Nerve.”

Sensorineural Hearing Loss

n Implications include:

A reduction in the sensitivity of the receptor cells in the cochlea

A reduction in the frequency resolving power of the cochlea

A reduction in the dynamic range of the system

Mixed Hearing Loss

“A loss with both a conductive and sensorineural component.”

Auditory Nervous System Impairment

Causes:

Disease Disordered auditory nervous system

development

Auditory Nervous System Impairment

Kinds:

Retrocochlear disorders Central auditory processing disorders

Auditory Nervous System Impairment

§ Auditory Characteristics:

Reduced ability to understand speech in a noise background

Problems understanding speech with reduced redundancy

Problems with localization and lateralization Problems processing normal or altered

temporal cues

Auditory Pathologies

Outer and middle ear disorders Conductive pathologies

Cochlear disorders Sensorineural pathologies

Central auditory disorders Central auditory pathologies

Outer and Middle Ear Disorders

Structural defects due to embryologic malformations

Structural changes secondary to infection or trauma

Microtia

“an abnormal smallness of the auricle”

Atresia

“the absence of an opening of the external canal”

Outer Ear Disorders

Perforation of the tympanic membrane

Middle Ear Disorders

Otitis MediaMost common cause

of transient conductive hearing loss in children

Inflamation of the middle ear

Caused by eustachian tube failure

Otitis Media Facts

76-95% of all kids will have one episode of OM by age 6Prevalence is highest during the first two years of life50% of all kids with one episode before their first birthday

will have 6 or more bouts within two yearsMost episodes occur in winter and springRisk factors

Cleft palateDown syndromeNative AmericansUrban poorDay careSecondhand smoke

Otosclerosis

n “a bone disorder that affects the stapes and the bony labyrinth of the inner ear. The disease process is characterized by resorption of bone and new spongy formation around the stapes and oval window”

Otosclerosis

Facts:

Hereditary Women are more

likely to develop the disorder

Usually bilateral

Progressive

Cochlear Disorders

Syndromes and inherited disorders

Syndromic disorders

Nonsyndromal disorders

Types of Nonsyndromic Disorders

DominantDominant

progressiveDominant

progressive with adult onset

Recessive hereditary SNHL

X-linked

Noise Induced Hearing Loss

n The degree of SNHL depends on

The intensity of the

noise

The spectral

composition of the noise

The duration of

exposure

Individual susceptibility

Infections

Congenital Cytomegalovirus HIV Rubella Syphilis Toxoplasmosis

Infections

Acquired

Herpes Zooster Oticus (Chicken Pox)

Mumps Syphilis

Presbycusis

Loss of hearing that gradually occurs in most individuals as they grow old.

It is estimated that 40-50 percent of people 75 and older have some degree of hearing loss.

It involves a progressive loss of hearing, beginning with high-frequency sounds such as speech.

Presbycusis most often occurs in both ears, affecting them equally

Central Auditory Disorders

VIII Nerve tumorsOther diseases of the

VIII NerveNeural disorders

Cochlear neuritisDiabetes mellitus

Brain Stem disordersInfarctsGliomasMultiple sclerosis

Temporal Lobe disorders

Hearing Assessment

Main questions

1. Is hearing normal?2. What is the degree

of hearing loss?3. What type of

hearing loss is it?

Hearing Assessment ProceduresBehavioral MeasuresMeasures of hearing behavior dependent

on the perceptions and cooperation of the listener

Nonbehavioral MeasuresAcoustic or physiological responses

recorded in association with an acoustic event

Pure Tone Audiometry

Major behavioral auditory measure Measurement of pure tone thresholds between 250-

8000 Hz Air conduction Bone conduction

Pure Tone Audiometry

The results of PTA tell us

1. Air conduction thresholds across frequency tells us if hearing is normal or not

2. If hearing by air conduction is NOT normal, the thresholds tell us the degree of hearing loss

Pure Tone Audiometry

The results of PTA tell us

1. If hearing is normal or not2. the degree of hearing loss3. Differences between hearing by air

conduction and hearing by bone conduction tell us the type of hearing loss

Air Conduction vs Bone Conduction Testing

Air conduction tests the entire auditory system. Bone conduction bypasses the conductive mechanism, so it tests only the inner ear.

The Audiogram

What the Audiogram Says About the Impairment

Within normal limits Mild

Moderate

Severe

Profound/deaf

Determining a Conductive Hearing Loss

Determining a Sensorineural Hearing Loss

Determining a Mixed Hearing Loss

Speech Audiometry

Another behavioral measure of auditory ability

Speech thresholdsSpeech Reception

thresholdSpeech Awareness

threshold

Word recognition testing

Identifying Hearing Loss Through the First Year

Communication checklists Parents’ reports Case history Informal observation Formal testing

Visual Reinforcement Audiometry Behavioral Observation Audiometry

Typical Response Levels to Sounds from Birth-2 years

Nonbehavioral Measures of Hearing

Auditory brainstem evoked response (ABER)

Nonbehavioral Measures of Hearing

Otoacoustic Emissions

Treatment

MedicalMost conductive hearing

losses, caused by pathologies in the outer and/or middle ear, can be treated successfully by medication and/or surgery

Treatment

AmplificationHearing aids are the most

common treatment of sensorineural hearing loss

Hearing aids amplify speech and other sounds

They work best for people with mild through severe degrees of hearing loss

Treatment

Cochlear ImplantsUsed for children and

adults who are deafThese devices stimulate

the auditory nerve directly

They are best for people who get very little benefit from conventional hearing aids

Treatment

Habilitation/RehabilitationAuditory Training

Children and adults

Communication StrategiesSpeechreading, noise management, assertiveness

training

Communication MethodsSign language, cued speech

Counseling