Hearing Impairment Flashcards
Hearing Loss
Disability
Culturally Deaf
Native language is sign language
Identify with the attitudes, traditions, values, and mores of deaf culture
Social identity – hearing loss is a difference NOT a disability
Hard of hearing as a difference
Speech is the primary means of communication
Individual chooses to construct their view of hearing loss
Congenital hearing loss
Present at birth or shortly after birth
Prelingual/Postlingual Hearing Loss
Prelingual loss – hearing loss present at birth or before speech and language have developed ( ~2 years of age)
~50% due to genetics
Postlingual loss – hearing loss occurs after speech and language development
The Speech Chain
Step 1: The speaker’s brain
The speaker organizes his/her message
What do you want to say; how do you want to say it
A complex process but takes seconds
Step 2: The speaker’s brain
The speaker formulates his/her message into language
Step 3: The speaker’s central nervous system The speaker’s brain sends neural impulses (signals) through the central nervous system to the muscles of: Respiration Phonation Articulation arms, hands, torso (for support), etc. Step 4: Sound waves Air flow from the larynx is constricted by the articulators creating pressure changes in the air surrounding the speaker’s mouth Intensity (decibels) amount of energy per unit of air Frequency (hertz) cycles per second These patterns of pressure changes are sound waves Pure tones – sound at one frequency Complex tones – have fundamental frequency, harmonics, and formants Sound waves travel through the air to reach the listener’s ear drum
The Speech Chain
Step 1: The speaker’s brain
The speaker organizes his/her message
What do you want to say; how do you want to say it
A complex process but takes seconds
Step 2: The speaker’s brain
The speaker formulates his/her message into language
Step 3: The speaker’s central nervous system The speaker’s brain sends neural impulses (signals) through the central nervous system to the muscles of: Respiration Phonation Articulation arms, hands, torso (for support), etc. Step 4: Sound waves Air flow from the larynx is constricted by the articulators creating pressure changes in the air surrounding the speaker’s mouth Intensity (decibels) amount of energy per unit of air Frequency (hertz) cycles per second These patterns of pressure changes are sound waves Pure tones – sound at one frequency Complex tones – have fundamental frequency, harmonics, and formants Sound waves travel through the air to reach the listener’s ear drum Step 5: The listener receives the sound waves The external ear receives the sound waves The middle ear converts sound into mechanical energy. The inner ear converts mechanical energy into electrical energy/signals. Electrical energy travels through the VIII cranial nerve (vestibulocochlear) to the auditory cortex. Step 6: The listener's brain The listener’s brain decodes the neural energy What brain structure? The speaker’s message is interpreted and received
Conductive Hearing Loss
Outer or middle ear dysfunction
Sound is softer
May be treated with medical or surgical intervention
Some causes:
Head trauma
Fluid in the middle ear
Perforated Eustachian tube
Otitis media
Can cause mild fluctuating hearing loss
May result in language delay
Sensorineural Hearing Loss
Damage/dysfunction of cochlea or VIII cranial nerve
Sound is softer and distorted (bc hair cells are tuned to specific frequencies; damaged cells no longer detect those frequencies)
Typically, can’t be medically or surgically corrected
Severity of hearing loss depends on location and number of damaged elements
Amplification may help with sound volume
Some causes:
Congenital – e.g., prematurity
Diseases – e.g., meningitis
Presbycusis
Mixed Hearing Loss
Combined conductive and sensorineural
Conductive component medically treated
Sensorineural loss persists
Central Auditory Processing Disorder – dysfunction in the brain’s ability to process auditory information (difficulty processing auditory information in the brain)
Diagnosed by an Audiologist
Speech-language pathologist is part of the multidisciplinary team
Academic challenges may be present
Hearing Assessment
Audiologist
Evaluates an individual’s hearing
Recommends and fits assistive listening devices
Speech Audiometry
Quantifies hearing threshold for speech
Speech Reception Threshold – minimum hearing level for speech
Recognize 50% of speech material
Used to confirm pure-tone results
Speech discrimination – repeat monosyllabic words presented at a comfortable listening level
Otoacoustic Emissions
Sounds emitted by the inner ear when the cochlea is stimulated by sound
The sound is measured by a probe inserted into the ear canal
The sound isn’t present with sensorineural or conductive hearing loss
Degree of Hearing Loss
Average of pure-tone thresholds at:
500, 1000, and 2000 Hz
Greater severity, greater the affect on communication
Age of onset
Children
Adults
Course of onset
Gradual
Rapid
Other factors
Hearing Aids
Types
Components:
Microphone
Amplifier
Receiver
T-switch
Direct audio input (DAI)
Behind the ear (BTE)
In the ear (ITE)
Canal aids
Body and eye glass aids
Bone conduction aids
Digitally programmable hearing aids
Pure Tone Audiometry
Pure-tone thresholds
Compares thresholds to normal hearing
Air conduction and bone conduction
Test frequencies of 125-8000 Hz
Audiogram
