OAE Review Flashcards
What do outer hair cells do?
They amplify movement of the basilar membrane during low-intensity sound stimuli
How do OHCs function?
They change their lengths in response to stimuli (electromotility)
When there is a greater change in length of the OHCs, what does that mean?
There is more stereocilia bending, more transduction and greater response
How much do OHCs improve our hearing sensitivity?
40 dB improvement
How much hearing loss do damages OHCs produce?
mild to moderate SNHL
Do OHCs sharpen the tonotopic organization of the basilar membrane?
Yes
What do IHCs do?
They serve as the actual sensory receptors of hearing
Transform sound vibrations present in cochlear fluids into electrical signals that can then travel the auditory nerve to the brainstem and auditory cortex
What type of hearing loss does IHC damage result in?
Severe to profound SNHL
What are OAEs?
The cochlea emitting sound
What are the different types of OAEs?
Spontaneous OAEs
Transient evoked OAEs
Distortion Product OAEs
Stimulus Frequency OAEs
What are spontaneous OAEs?
They are emissions that are not evoked
They occur naturally
They only occur in normal cochleas
Only occur in about 60% of normal ears
Are a majority of people unaware of spontaneous OAEs?
Yes
However, some perceive it as annoying tinnitus
Are spontaneous OAEs clinically useful?
No
What are transient evoked OAEs?
Present in individuals with normal hearing
Click stimuli (broad band)
Broad band responses
500 to 4000 or 5000 Hz
Amplitude averages 10-12 dB SPL in young adults
Why are clicks broad band?
They have spectral splatter
Can TEOAEs be used to screen infant hearing?
Yes
Can TEOAEs be used to validate thresholds?
Yes
Can TEOAEs be used to assess cochlear function relative to the site of lesion?
Yes
Is there frequency specificity for TEOAEs?
Limited
Response is broad
What are distortion product OAEs?
2F1-F2 results in the best emissions in humans
Two pure tones are presented simultaneously
What does 2F1-F2 tell us?
It gives us a 3rd frequency that is the one that comes out of the cochlea
Is the presence of DPOAEs dependent on hearing sensitivity in the region of the primaries?
Yes
Can DPOAEs be used to screen infant hearing?
Yes
Can DPOAEs be used to validate behavioral thresholds?
Yes
Can DPOAEs be used to assess cochlear function relative to site of lesion?
Yes
Can DPOAEs be used for ototoxic monitoring?
Yes
Do DPOAEs have greater frequency specificity?
Yes
What are stimulus frequency OAEs?
Newer, less common
Not clinically used
Measuring the stimulus and the emission and picking up the difference between them
Are OAEs used clinically to evaluate the health of the inner ear?
Yes
What are some non-pathologic factors that can influence OAEs?
Age
Gender
Ear difference
Diurnal effects (sleep-wake cycle)
Genetics
Race
Body temp
Body position
State of arousal and attention
Poor probe placement
Ear canal acoustics/standing waves
Debris, cerumen, foreign objects
Uncooperative patient
Noise
How to minimize the effect of noise on OAEs?
A deep and secure probe fit
An adequate number of stimulus repetitions
Appropriate stopping criteria
Emphasis on or exclusive presentation of signals at frequencies higher than 1 kHz
A protocol that presents signals from higher to lower frequencies (DPOAE)
