CSD429 exam 2

when is masking used for air conduction?

>40dB difference between R&L unmasked air conduction

when is masking used for bone conduction?

>10 dB difference between the unmasked bone and air conduction

what is SRT and how do you find it?

Speech Reception Threshold: the lowest level at which speech can be understood 50% of the time. Usually presented through headphones or speakers.

What is SDT and how do you find it?

Speech Detection Threshold: the lowest level at which speech can be detected, regardless of understanding. Usually determined using spondee words presented at various intensity levels.

how do you find speech discrimination testing level?

40+SRT, if this is >90, test at MCL

what is immittance audiometry?

test of ME function used to assess compliance (movement of TM), ear canal volume, pressure of ME

what equipment is used for immittance audiometry?

Speaker (delivers sound), Sound level meter (measures sound intensity), Air pump (changes pressure), Manometer (measures pressure)

what is the procedure for immittance audiometry?

insert probe into ear canal, probe changes air pressure and introduces sounds to measure the response of the eardrum and middle ear muscles

what types of tympanograms are there?

A, As, Ad, B, C

type A tympanogram

normally functioning ME

type As tympanogram

Normal pressure, minimal compliance, shallow, stiff

type Ad tympanogram

normal pressure, large changes in compliance, hyper ear canal movement, ossicular discontinuity

type B tympanogram

no change in compliance, ear drum is immobile, fluid in ME, otitis media with normal ear canal volume, large volume=TM rupture, small volume=ear wax

type C tympanogram

normal compliance with negative ME pressure, eustachian tube dysfunction

spontaneous OAE

Sounds that are naturally produced by the cochlea (outer hair cells) without any external sound stimulus, Present in about 40–60% of normal-hearing ears

evoked OAE

Sounds generated by the cochlea in response to an external auditory stimulus

SFOAE

Stimulus frequency OAE: Pure tone stimulus presented to ear

DPOAE

distortion product OAE: two pure tones (f₁ and f₂) presented simultaneously, The cochlea produces a “distortion” tone (2f₁–f₂), identify outer hair cell damage

TOAE

Transient OAE: uses a quick click sound that spans most frequencies