1 - Audiograms Flashcards
What is Degree of Hearing Loss?
The intensity level at which a person perceives sound
What are the four parameters used to describe individual hearing sensitivity/impairment?
Degree of Hearing Loss
Configuration of Hearing Loss
Type of Hearing Loss
Symmetry of Hearing Loss
What can we learn from Degree of Hearing Loss?
When someone scores outside the range of normal hearing, this indicates impairment
What is Configuration of Hearing Loss?
The degree of loss across test frequencies
What can we learn from Configuration of Hearing Loss?
It shows the shape of the hearing loss pattern on a graphical display
What is Type of Hearing Loss?
The characteristic that indicates the location or structure that is causing impairment
What is Symmetry of Hearing Loss?
A comparison of the test results from both ears
What is Threshold of Audibility?
The softest sound still audible
How is Threshold of Audibility measured?
In 5 dB increments using pure tones
What is Sound Pressure Level?
An intensity measurement
dB SPL
What is Absolute Sensitivity?
Another name for threshold of hearing
What is a Minimal Audibility Curve?
A graph of the audibility threshold using frequency and intensity in dBs
The graph is usually a curve
What is Hearing Level?
An intensity scale that references normal hearing thresholds
dB HL
Audiometric Zero
The sound pressure required to reach a threshold of audibility for each frequency
0 dB HL
What is an Audiogram?
A graphical representation of hearing test results
The frequencies used in audiograms are __________________.
Consistent with musical octaves
What are Audiometric Symbols?
Sets of symbols used for displaying hearing test results
They communicate what sort of test was used and what ear was being tested
What is Air Conduction Testing?
Testing using earphones or a sound field
What is Bone Conduction?
Testing using a bone vibrator
What is Sound Field Testing?
Testing using speakers
What is the range for Normal Hearing?
-10 to 15 dB
Up to 25 for the purposes of our course
What is the range for Slight (Minimal) Hearing Loss?
16 to 25 dB
What is the range for Mild Hearing Loss?
26 to 40 dB
What is the range for Moderate Hearing Loss?
41 to 55 dB
What is the range for Moderately Severe Hearing Loss?
56 to 70 dB
What is the range for Severe Hearing Loss?
71 to 90 dB
What is the range for Profound Hearing Loss?
> 90 dB
What are the symptoms of Slight (Minimal) Hearing Loss?
Fatigue
Miss some speech sounds and cues from a distance
Can affect education performance
What are the symptoms of Mild Hearing Loss?
Miss some speech sounds
Can be issues in developing clear speech
What are the symptoms of Moderate Hearing Loss?
Conversational speech inaudible
Loss of some environmental sounds
Strong negative impact on communication
What are the symptoms of Moderately Severe Hearing Loss?
100% of conversational speech is inaudible
Amplification is required to use hearing
What are the symptoms of Severe Hearing Loss?
Unable to perceive speech and environmental sounds
Some possible benefit to amplification
What are the symptoms of Profound Hearing Loss?
This person will be considered deaf
Very few people have absolutely no hearing at all
What is an Audibility Index?
A window of measurement that covers the wide range of frequencies and intensities used in normal speech
How can hearing descriptors be misleading?
They may sound more benign that the actual impairment
Do both our ears have similar thresholds of hearing?
No. This is rare.
A 5-10 dB difference is considered symetrical
When there is asymmetrical hearing loss, ____________.
Each ear is usually described separately
What does an audiogram look like?
X-Axis = 125, 250, 500, 1000, 2000, 4000, 8000, Hz
Y-Axis = -10, 0, 10, 20, 30…..100, 110, 120 dB HL
+ there might be a masking chart
What is Absolute Threshold?
Any measurement of auditory sensitivity with respect to some absolute physical level (such as dB or μP)
Absolute threshold is a _________ concept
Statistical
How is absolute threshold usually defined?
The lowest level a person indicates they can sense in at least 50% of trials
Is threshold a direct property?
No, it can be influenced by factors other than hearing sensitivity.
Always specify your ________ and ________.
Measuring units (dB SPL, dB HL, etc.)
Conditions of measurement (Coupler, real ear, sound field, etc.)
Minimal Audible Pressure (MAP)
Real Ear SPL
Threshold measurements taken at the lateral surface of the TM
Why are Real Ear SPLs rarely done?
A tube must be inserted all the way down to the eardrum
This is invasive and uncomfortable
When might a Real Ear SPL measurement be made?
When fitting a hearing aid
What is used instead of a Real Ear SPL? Why?
A Coupler SPL
It usually offers the same acoustic impedance as the human ear under an earphone
What must you do when using a coupler?
Specify the earphone type and the coupler type
What are couplers used for?
Audiometer calabration
Testing hearing aids
Other psychoacoustic measurements
Minimal Audible Field (MAF) Measures
The threshold SPL measurements taken where the head of a listener would be during a test
Free-Field
No reverberation
Sound Field
Some Reverberation
How is a MAF performed?
By using a sound level meter to measure SPL at the subject’s location (where the center of their head will be)
How is MAP performed?
By using a sound level meter and coupler (with headphones) to measure SPL
Are all measurements of absolute hearing sensitivity the same?
No, measurements will differ across methods
MAF ≠ MAP
What is Relative Hearing Sensitivity?
Measures of auditory sensitivity with respect to an absolute measure of auditory sensitivity
Where is Relative Hearing Sensitivity normally used?
During audiometric hearing tests
Audiometric 0 (0 dB HL) is
On an audiogram, does 0 mean the absence of sound?
No
What is a Pascal?
A unit of pressure
On a Threshold of Audibility Curve measured in dB SPL, the thresholds are the basis for _______.
0 dB HL
What does a Threshold of Audibility Curve show?
The minimum threshold levels by frequency
What does “Base Zero” refer to?
0 dB HL
A pure tone is a ____________.
Simple sinusoid
What are the measurements for the dynamic range of hearing?
20 dB to 20,000 dB
What is the frequency range of speech?
250 Hz to 8,000 Hz
What frequencies does ASHA recommend plotting on an audiogram?
125 Hz to 8,000 Hz
Why do we measure hearing for different frequencies?
Different speech sounds occur at different frequencies
Different environmental sounds occur at different frequencies
Those with hearing loss will _______ certain sounds and often will hear sounds as ___________.
Miss
Mumbled or garbled.
Those with hearing loss may ______ but not ______.
Hear
Understand
When is a bone conduction test usually performed?
During a patient’s intake. It is not usually performed again until the patient has an abnormal air test
Don’t use the word ________________ with the deaf.
Hearing Impairment
What is Auditory Impairment?
That there is a dimension of the auditory system that is outside the normal range
What does the term “Auditory Impairment” NOT specify?
Any restrictions in the level of performance of the individual
What is a Disability?
Any restriction or lack of ability to perform an activity in the range that is considered normal
This is due to an impairment
What is the difference between and impairment and a disability?
Impairment = Loss of function
Disability = Loss of ability
What are two organizations that have their own hearing impairment classification systems?
American Academy of Ophthalmology and Otolaryngology
Veteran’s Administration
Why do most audiologists not like hearing impairment classification systems?
They don’t describe the effect!
Hearing Level is not _________. Why?
Hearing Loss
Hearing Level = A threshold reference for audiologists
Hearing Loss = Measured against the above thresholds
What are the limitations to gaging the percentage or degree of hearing lost?
Individuals with the same degree of hearing loss may experience very different auditory abilities in everyday life
SNR
Signal to Noise Ratio
An audiogram cannot predict how ______________.
4
Someone’s hearing works in a noisy environment
Someone’s temporal resolution
Someone’s frequency resolution
Someone’s physiology is working or malfunctioning
Why do we need good temporal resolution?
To understand speech
How can audiologists avoid confusing patients and family members with hearing loss classifications?
By fully explaining the problems the listener will be expected to have
Do all pathologies create hearing loss?
No
Classifications for hearing loss and descriptions of audiometric configurations only refer to __________.
Air Conduction Thresholds
How many times must a patient respond before before a threshold can be determined?
3 times
When are inter-octaves tested?
When there is a 20 dB (or greater) difference between octaves
When plotting an audiogram, do you connect responses and nonresponses with lines?
No
At what intensity level do we usually begin a hearing test at?
50 dB HL
Which masking symbol do you plot on an audiogram?
The one for the ear being tested
What is the difference between absolute sensitivity and absolute threshold?
Absolute sensitivity is the minimum threshold of audibility.
Absolute threshold is a way of measuring auditory sensitivity.
Is it always obvious that someone can’t hear?
No
For class, normal hearing is?
-10-25 dB HL
For class, mild hearing loss is?
25-40 dB HL
For class, moderate hearing loss is?
40-70 dB HL
For class, severe hearing loss is?
70-90 dB HL
For class, profound hearing loss is?
Anything greater than 90 dB HL
What’s the difference in Absolute Threshold vs. Absolute Sensitivity?
They basically mean the same thing.
Absolute Threshold has to do with a physical measurement reference - usually μP
What to we use to measure absolute threshold?
Couplers
Sound fields
Earphones
When do we use dB SPL versus dB HL?
SPL used for regular sound measurement
HL used solely for hearing tests
What is the difference between Absolute Threshold and Relative Threshold?
Absolute Threshold for sound measurement. It is measure against some absolute measurement.
Relative threshold for hearing tests. It is compared against a standard of normal thresholds
How does ASHA recommend that an audiometric test be started?
1000 Hz at 30 dB (for normal hearing)
