Otoacoustic Emissions

Question 1

Otoacoustic emissions is a test of _________ function.

Answer 1

Cochlear

Question 2

Otoacoustic emissions tests are (subjective/objective)

Answer 2

Objective

Question 3

Otoacoustic emissions do not indicate hearing ________

Answer 3

sensitivity

Question 4

The gold standard for hearing sensitivity is:

Answer 4

pure tone audiometry

Question 5

low-level acoustic signals of cochlear origin that may be recorded within the ear canal

Answer 5

Otoacoustic emissions (OAEs)

Question 6

OAEs are sounds from the cochlea that are transmitted back through the _____ ear to the ______

Answer 6

middle ear to the external ear canal

Question 7

OAEs are generated as a byproduct of:

Answer 7

the active process in a normal cochlea (the hair cells)

Question 8

The most probable origin of OAEs are the:

Answer 8

outer hair cells

Question 9

OAEs are absent in cases with:

Answer 9

outer hair cell loss

Question 10

any signal presented to the ear has two components:

Answer 10

forward transmission

backward transmission

Question 11

when the signal reaches the outer hair cells, the active processes generated by the OHCs causes a ‘ripple’ that moves backward along the traveling wave.
The ‘ripple’ is transmitted back through the ossicular chain in the middle ear and then converted to an acoustic signal by the TM.
This is called:

Answer 11

Backward transmission

Question 12

The signal proceeds through the auditory system in an efficient manner.
This is called:

Answer 12

Forward transmission

Question 13

Forward transmission travels along the ________

Answer 13

normal auditory pathway

Question 14

During forward transmission the TM:

Answer 14

acts as a ‘microphone’

Question 15

During backwards transmission the TM:

Answer 15

acts as a ‘loudspeaker’

Question 16

The acoustic signal/acoustic emissions is very ______, ranging from __ to __ dB SLP, and is directly related to the level of the stimulus.

Answer 16

small; 0 to 20

Question 17

Emissions only occur in _____ cochlea

Answer 17

Healthy - the outer hair cells need to be functioning in order to produce emissions

Question 18

Technology to test OAEs

Answer 18

A probe assembly is seated in the ear canal (similar to tympanometry). The probe contains two ports:
1. Loudspeaker
2. Microphone
The microphone picks up the low level emissions and feeds them to a computer for signal averaging

Question 19

Testing OAEs is subjective/objective and noninvasive/invasive.

Answer 19

Objective and noninvasive

Question 20

What are the two types of OAEs?

Answer 20

Spontaneous OAEs
Evoked OAEs (2 - Transient Provoked, Distortion Product)

Question 21

Type of OAE that occurs in the absence of acoustic stimulation

Answer 21

Spontaneous OAEs

Question 22

Type of OAE where a stimulus is required to elicit a response

Answer 22

Evoked OAEs

Question 23

Spontaneous OAEs are very ____ level: about ___ to ___ dB SPL

Answer 23

low level; -10 to 10 dB SPL

Question 24

Spontaneous OAEs ____ in size and ____ in old age. They are ____ in frequency regions with a hearing loss.

Answer 24

decrease in size and disappear in old age.

Question 25

(T/F) Spontaneous OAEs have no diagnostic significance.

Answer 25

True - they are not used clinically

Question 26

About ____% of people with normal cochlea have spontaneous OAEs

Answer 26

50%

Question 27

OAEs elicited using a click stimulus

Answer 27

Transient Evoked OAEs (TEOAE)

Question 28

In transient evoked OAEs, the characteristics of the click includes:

Answer 28

1. clicks stimulate a wide range of frequencies along the basilar membrane
2. produces a wide range of OAEs across frequencies
3. they occur about 4 msec after the onset of the stimulus and last about 10 msec
4. they are small in amplitude but stable over time
5. the amplitude of the emissions grows nonlineraly with the stimulus level and eventually plateaus
6. usually present between 1000 and 5000 Hz in normal ears
7. absent at frequencies with thresholds >30 dB HL

Question 29

these OAEs are evoked by presenting two tones simultaneously; the two tones interact to produce a third tone

Answer 29

Distortion product DPOAE (a type of evoked OAE)

Question 30

In distortion product OAEs, the third tone can be calculated based on the relation between the two tones. This formula is:

Answer 30

(2F1-F2), where F2 is the higher of the two frequencies

Question 31

Distortion product OAEs are present in _____ ears for frequencies between ____ and ____ Hz

Answer 31

normal ears; 1000 and 8000 Hz

Question 32

Distortion product OAEs are ____ in amplitude

Answer 32

small

Question 33

In distortion product OAEs results below ____ Hz are often contaminated by background noise

Answer 33

2000

Question 34

Distortion product OAEs are absent in individuals with thresholds ______ dB HL

Answer 34

> 40 dB HL

Question 35

Transient evoked OAEs, are _____ in amplitude, but ____ over time.

Answer 35

small; stable

Question 36

we use DPOAE’s when we are interested in:

Answer 36

more specific frequency information

Question 37

Transient evoked OAEs are present at frequencies between ____ and ____ Hz in normal ears.

Answer 37

1000 and 5000 Hz

Question 38

Transient evoked OAEs are absent at frequencies with thresholds ______ dB HL

Answer 38

> 30 dB HL

Question 39

In relation to hearing sensitivity, OAEs:

Answer 39

Are not an indication of hearing threshold - the emissions are cochlear responses

Question 40

Results of OAEs can be used to tell if there is or is not a:

Answer 40

cochlear hearing loss at specific frequencies

DOES NOT tell us the degree of loss

Question 41

After you look at the results, you only know if the thresholds are better than ____ dB HL for TEOAEs or better than ____ dB HL for DPOAEs and only for ______ frequency regions.

Answer 41

30; 40; specific

Question 42

______ pressure in the middle ear affects the response to OAEs; the largest OAEs occur at the tympanometric peak pressure

Answer 42

Negative

Question 43

Presense of middle-ear liquid will _______ OAEs

Answer 43

obliterate

Question 44

Clinical application of OAEs: (3)

Answer 44

1. Identify individuals with potential hearing loss - newborn hearing screening, difficult to test patients, functional hearing loss
2. Monitor changes in cochlear function - ototoxicity, progressive hearing loss, noise exposure
3. Differential diagnosis (cochlear vs. neural) - OAE measures are useful for narrowing the site of lesion to areas peripheral or central to the outer hair cells.