Pure Tone Audiometry Flashcards
Pure Tone Audiometry
Done with audiometer
Find hearing threshold
Frequences range from 125Hz to 20,000Hz
Typically test 250 Hz to 8 kHz; No speech information after 8K Hz
“High Frequency Audiometry” goes from 8 to 20 kHz; reserved for those at risk: military, cancer patient or anyone receiving ototoxic drugs
-10dBHL to 120dBHL Loudness Level
Typically stop around 110
Bone conduction:
250 Hz to 4 kHz – equipment can only be calibrated to 4kHz
Stop between 50 dBHL and 80 dBHL; After this vibration felt and not heard; vibrates on head
Threshold
when patient hears the tone 50% of the time
Interaural attenuation
crossover
Inserts = 60 dBHL difference level will crossover
Headphones = 40 dBHL difference level will crossover
Air Conduction Audiometry
Proper placement is super important
Inserts = preferred over headphones
Procedure
Begin at 1kHz and then go up to 8kHz then back down
Begin at 30 dBHL
Increase to 50 dBHL if no response
Increase in 10 dBHL increments if no response at 50 dBHL
Once they respond, follow the “down 10, up 5” method
Plot on audiogram
Use pulsed warble (pure) tones
Play 2-3 beeps, longer if needed
PTA – average of 500, 1000, & 2000 Hz
If the difference btwn octaves is 20 dB or more, test the inner octaves as well
Bone Conduction Audiometry
Purpose: see their sensorineural sensitivity
CHL/MHL vs SNHL
Placed on the mastoid, under hair: Loudest behind the ear because you have added benefit of middle ear bone movement from vibration as well
Glasses & pinna will vibrate if touched with sensor; cause false positive
Same method as air conduction (start at 1kHz; up then down)
Tactile response (felt)
Cross Hearing (interaural attenuation is 0 bc everything vibrates)
If the difference btwn octaves is 20 dB or more, test the inner octaves as well
Sensorineural HL on Audiogram
AC & BC outside of normal
Air-Bone Gap
Mixed HL on Audiogram
AC & BC outside of normal
Air-Bone Gap
>10 dBHL between AC and BC
Conductive HL on Audiogram
AC outside of normal, BC within normal
Air-Bone Gap
>10 dBHL between AC and BC
Other types of Audiometry
Automatic Audiometry: Smartphone applications; generally not reliable
Computerized Audiometry: Mostly for research
Masking
AKA: Interaural attention, Cross hearing
What does it do:
Distracts one ear so you know the response is true: a “masked response”
BC Masking
Bone conduction is tested to determine if there is SN HL; check the difference btwn AC tests; if more than 10dB difference, must mask for BC testing
BC masking requires both ears to be masked and tested, one at a time, to get the threshold for each ear
AC Masking
Required when there is sufficient difference btwn SL in the ears
Headphones: 40 dBHL
Inserts: 60 dBHL
