topic 1

TOPIC 1

TYPES OF HEARINGIMPAIRMENT

Types of Hearing Impairment

A loss of sensitivity Auditory nervous system

pathology

Important TermsTime of onset

Congenital: present at birth Acquired: obtained after

birth Adventitious: acquired after

birth

Important Terms

Time Course

Acute: sudden onset/short duration Chronic: long duration Sudden: rapid onset Gradual: changes slowly over time

Important TermsTime Course

Temporary: limited duration Permanent: irreversible Progressive: advancing Fluctuating: changes in degree

over time

Important TermsNumber of Ears Involved

Unilateral: Just one

Bilateral: Both

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”

Conductive Hearing Loss

An audiogram of a bilateral conductive hearing loss

Conductive Hearing Loss

Differences in the air-bone gap across different types of hearing loss

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

Sensorineural Hearing Loss

An audiogram of a bilateral sensorineural hearing loss

Sensorineural Hearing Loss

Differences in the air-bone gap across different types of hearing loss

Mixed Hearing Loss

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

Mixed Hearing Loss

An audiogram of a bilateral mixed hearing loss

Mixed Hearing Loss

Differences in the air-bone gap across different types of hearing loss

Types of Hearing Impairment

A loss of sensitivity

Auditory nervous system pathology

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