Pure-Tone Audiometry Flashcards
Why do we measure thresholds?
To see if someone can detect sounds
1 octave = mm on the basilar membrane
5 mm
Why do we use 1 frequency in pure-tone audiometry?
for Place Specificity and we use low sound pressure to be as place-specific as possible
What affects performance in real life? (5)
Accent/Language issues
Background noise
Cognitive issues (Dementia)
Age
Attention
Why is the audiogram upside down?
As the hearing level goes up then the fact that it goes down it shows hearing loss
Why does the audiogram go in steps of 10dB
Because of the variability of the results and the fact that adding 10 is roughly two times as intense
Why do we use octaves in the audiogram?
Frequency discrimination gets broader as you go up in frequency
1 speech feature/piece of information per octave
Regular physical tonotopic on the BM (5m)
What does the 0 represent on the audiogram?
The lowest sound level we can detect on average
Why does the transfer function in the ME is low before and after 1000 Hz?
Stiffness of the ossicles affects the transmission of low Frequencies and Mass of the ossicles affect the high frequencies
What is RETSPL? (2)
- Reference equivalent threshold sound pressure level
- level of average threshold
- this is subtracted so that average is zero
How do we calculate HL using RETSPL?
If someone hears 26.5 dB at 250 Hz you subtract the RETSPL at this frequency 26.5 -26.5 so the HL is 0
What is a threshold?
- The level at which a person hears a tone 50% of the time (i.e., a hit rate of 50% or .5)
- The point of Maximum uncertainty
In what dB steps and Octave steps do we do our Pure-tone test?
5 dB steps
1 octave (125, 250, 500, 1000, 2000, 4000, 8000)5mm steps along BM
On the audiogram, what do the O and X represent?
O = Right air conduction
X = Left air conduction
On the audiogram, on what side is the right ear and left ear charts?
Right ear on theLeft side of the audiogram
Left ear on the Right side
What are the degree levels of hearing?
Normal -10 to 25 dB
Mild up 26 - 40 dB
Moderate up 41 - 55 dB
Moderately Severe up 56 -70 dB
Severe up 71 - 90 dB
Profound up 91 dB
What is the device/machine we use for testing?
The Clinical Audiometer
What does the clinical audiometer do? (9)
Oscillator (for pure tones)
Noise generator
Amplifier/Attenuator
Signal router
Presentation Ctl
Interrupt (Plays sound continuously)
Talk Forward Lvl
Talk Forward Btn
Microphone Lvl
Which device is this?
Ipad base audiometer called Shoebox
Which device is this?
Most popular audiometer GSI
Which device is this?
The Screening Audiometer
What is the first step in measuring?
Control
Calibrate the earphone/microphone using 6cc 2cc couplers
What does this table represent?
Ambient Noise is permissible depending on RETSPL
What is the difference between these devices?
On the left: supra-aural Earphones
On the right: Inserts Earphones
Which earphones do we use the most in clinic?
TDH 49/50
What are the pros of Insert Earphones?
Pros:
More Stable
More Hygenic
No collapsing canal
Better in areas of higher ambient noise than was previously possible
Improved patient comfort
What are the pros and cons of Supra-aural Earphones?
Pros:
Much easier to store, carry, and wear during daily activities and commutes
Cons:
Can cause collapsing canal
Less hygienic (used over and over again)
When would we use speakers (sound field)?
- If kids won’t accept earphones
- Spatial hearing
- Environment testing
What are dial readings?
This means my audiometer is creating a certain dB HL in the coupler, not the same level in every. Helps to match the same dB HL in the earphones.
What is the difference between sending 40 dB SPL in huge vs baby ears?
Can make wrong conclusions hearing loss of huge ears because less pressure will be felt compared to baby ears
What device do we use for BC audiometry?
Bone Oscillator on the mastoid bone
What is Cochlear fluid inertial stimulation?
- when the bone of the cochlea is vibrating, the perilymph will try to “stay put”
- this is fluid inertia (from the mass of the fluid) and because there is a little space in the round window, the fluid will be able to move back and forth
What is Cochlear fluid inertial stimulation?
- First and most important mechanism of BC
- when the bone of the cochlea is vibrating, the perilymph will try to “stay put”
- this is fluid inertia (from the mass of the fluid) and because there is a little space in the round window, the fluid will be able to move back and forth
Why is cochlear inertial stimulation useful?
Bypass OE and ME and help diagnose SNHL
What is the second Mechanism in BC?
Ossicles Inertial Stimulation helpful to diagnose Otosclerosis
What is the third mechanism of BC?
Osseotympanic stimulation
What are the types of Hearing loss?
Conductive HL
Sensorineural HL
Mixed loss
Explain this picture:
What does an ABG mean in the audiogram
Conductive Loss
What is the Weber test?
- Tuning fork is placed on center of forehead to measure for lateralization/centered for SNHL
- Sound heard on side with better cochlea, or on side with conductive loss
What is the Rinne test?
- Principle: sound decays faster via bone conduction
- Fork is held on mastoid until no longer heard, then immediately placed in from of canal
- If sound is still heard (via AC), this means no conductive loss: a POSITIVE RINNE
- If sound is not heard (via AC), this suggests conductive loss: a NEGATIVE RINNE
What is the Bing test?
- tuning fork is held on mastoid, while tragus is held against canal
- sound should get louder when ear is plugged (occlusion effect), but this will not likely occur with conductive loss
- If sound gets louder (no conductive loss), this is a POSITIVE BING
- If sound does not get louder (conductive loss), this is a NEGATIVE BING
What are the ways ORL’s use to report hearing loss?
Percentages:
% Impairment
avg threshold at (.5,1,2,3 kHz) - 25 dB x 1.5
0% = 25 dB = No hearing loss
100% ≈ 90 dB = Profound
or
% Disability
(better ear x 5 + worse ear) / 6
What are the second of way to describe hearing loss?
The Pure Tone Average:
average of 500, 1000 & 2000 Hz
the Fletcher average: best two of three
What is the best way to describe hearing loss?
Degree, Type, Configuration
What are 5 configurations (shapes) of hearing loss and what is the rule?
Rules of 20 dB change Slopping, Rise, Flat, Ski slope, Cookie bite
How would you describe this audiogram? (Degree and configuration)
How would you describe this audiogram? (Degree and configuration)
How would you describe this audiogram? (Degree and configuration)
How would you describe this audiogram? (Degree and configuration)
How would you describe this audiogram? (Degree and configuration)
How would you describe this audiogram? (Degree and configuration)
What is the difference between Congenital, Acquired and Adventitious?
Congenital : present at birth
Acquired: obtained after birth
Adventitious: acquired from an external source (not innate)
Acute:
sudden and short
Chronic:
long duration (not used for pure tone thresholds)
Sudden:
rapid onset
Gradual:
occurring in small degrees
Temporary:
limited duration
Permanent:
irreversible (PTS vs. TTS)
Progressive:
advancing in severity
Fluctuating:
a periodic change in degree
What are the symbols for:
- Right/Left Unmasked:
Earphone, Mastoid Bone - Right/Left Masked:
Earphone
Mastoid Bone - Unspecified
Mastoid Bone
Forehead Bone
Soundfield
What is this screening arrangement?
Typical screening arrangement
What is this screening arrangement?
Diagnostic arrangement
Who should place the transducer?
Clinician only
