Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

AUD fall 2019 electrophys I > Week 9 Suppression > Flashcards

Week 9 Suppression Flashcards

1
Q

disorders associated with ANSD (6)

A
  • anoxia
  • hyperbilirubinemia
  • immune disorders
  • mitochondrial diseases
  • neurological disorders (charcot-marie-tooth)
  • syndromes like waardenburgs
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what is ANSD

A

impairment of the peripheral auditory function with the preservation of OHC integrity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

site of lesion with type I ANSD

A

impaired function of the auditory nerve due to demyelination

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

site of lesion with type II ANSD

A

lesion involving the IHC or the synapses between the IHC and the nerve fibers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what are the 3 impacts of demyelinization

A

1) affects the high discharge rate associated with loud sounds which affects loudness encoding
2) more sensitive to temperature changes
3) cross-talk between fibers (one fiber activates its neighbor)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

SP/AP with dysynchrony of afferent fibers

A

there will not be a nice SP/AP, neural discharge patterns change with demyelinization or axon loss (causes fibers to no longer fire at the same time, making the signal weaker)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

audiogram with ANSD

A

can be any degree and configuration (SNHL)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

speech testing with ANSD

A

disproportionately affected in comparison to audio

—particularly affected by noise

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

acoustic reflexes with ANSD

A

absent, but can be present and abnormal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

ABR with ANSD

A

abnormal (absent or delayed wave V)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

OAEs and CM with ANSD

A

typically present

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

vestibular testing with ANSD

A

can be abnormal but they are normally asymptomatic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what polarity should be used when testing suspected ANSD with AEP

A

both condensation and rarefaction instead of just alternating to give more info

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what rate should be used when testing suspected ANSD with AEP

A

if expecting neuropathy, want to do slower rate than the normal 27 clicks /sec because the nerve is struggling so maybe 11 clicks/sec or 3 clicks/sec to show better response

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

success of CI with ANSD

A
  • pts with ANSD can be CI candidate
  • -if site of lesion is IHC they should do well with CI
  • -if site of lesion is demyelination of auditory nerve, they probs wont do very well with CI (maybe better than HAs though)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

MOC fibers compared t LOC fibers

A

MOC is thicker, more myelinated, and synapses direction to the OHCs it innervates while LOC synapses on the nerve fibers of the IHCs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

crossed and uncrossed fibers of the MOC vs LOC

A
  • 2/3 of the LOC are uncrossed, 1/3 of the MOC are crossed
  • –this means they are activated during contra stimulation
  • 2/3 of the MOC and 1/3 of the LOC is crossed
  • –this means they are ipsilateral
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

three potential functions of the auditory efferent system

A

1) protect from acoustic trauma
2) hearing in noise
3) attention

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

five subject factors influencing suppression

A
  • inhibition increases with developmental age (infancy to childhood)
  • reduction in inhibition is associated with older age, with greater reduction for binaural stimulation
  • females have more suppression than males
  • right ear has more than left
  • SNHL affects suppression, also also have less robust or absent OAEs so harder to evaluate suppression
20
Q

suppression with SOAEs and SFOAEs

A
  • some studies have focused on these
  • nice because not interfering wiht what is going on in same ear
  • won’t activate acoustic eflec
  • stimulus cant cancel out the response
  • with SOAEs, activating efferent system equals a decrease in amplitude of the response
  • also can cause a frequency change of the response of usually about 5 Hz, but up to 30 Hz, however, not all normal hearing adults have SOAEs
21
Q

suppression of DPOAEs and TEOAEs

A

frequnecy of the response will not change with suppression, but response is suppressed and loses amplitude

22
Q

two different factors that can have an affect on the attempted measurement of the efferent system

A
  • acoustic reflex, which would also reduce the response

* mechanical suppression which is when there are two traveling waves and one cancels the other out

23
Q

problems with bilateral or ipsilateral presentation of the suppression noise for OAEs

A
  • could show either the effects of the efferent system, the acoustic reflex, or mechanical suppression
  • –the latency of mechanical suppression is shorter than latency of AR and efferent activation affecting response
24
Q

what needs to be done with bilateral or ipsilateral suppression to ensure what is seen is resulting from the efferent system

A
  • use forward masking paradigm to see response to click without having mechanical suppression with still having efferent suppression
  • to avoid having effect of acoustic reflex in response, need to have click at an intensity that is not loud enough to activate acoustic reflex
  • –this would leave only the efferent effect
25
Q

contralateral stimulation advantage

A

just worried about acoustic reflex being activated, dont have to worry about mechanical suppression

  • –can now present click and noise at the same time
  • –however contra effect is small compared o bilateral stimulus which gives largest effect
26
Q

what works best to suppress TEOAEs

A

BBN signals, the greater the bandwidth of the noise, the greater the effect

27
Q

how to best suppress pure tone

A

elicitors 0.5-1 octave below the OAE evoking stimulus

28
Q

how to measure contra ellicitor suppression

A
  • measure OAEs with no noise
  • present noise in contra ear and measure OAE response again
  • –the difference between the two is the efferent system
29
Q

how to measure ipsi elicitor suppression

A
  • present noise to activate efferent system
  • wait a bit and the measure OAEs
  • —lose some of the efferent system effect because the latency is only about 5-10ms
  • –fast decays in 10-100 ms after noise is turned off and wait 40-50 msec to measure when testing
30
Q

is a lower or higher intensity better for suppression

A
  • lower intensity is better
  • –TEOAEs: click stimuli between 50-60 dB peSPL vs 80 dB peSPL
  • –DPOAE: stimulu less than 60-65 dB SPL
31
Q

best frequencies to see suppression with DPOAEs

A

1.5-4kHz (note the cubic difference tone 2F1-F2 shows less suppression than the quadratic difference tone F2-F1

32
Q

best frequencies to see suppression with TEOAEs

A

1-2kHz

33
Q

measuring ECochG suppression

A

AP is suppressed in amplitude with OCB activation

  • CM amplitude is increased wit MOC activation
  • –efferent system increases the amount of voltage change in OHCs so CM increases
  • ——-AP is suppressed because the signal is reduced to the neurons
  • not much change to ECochG with ipsi, but with contra there is change
34
Q

factors in children leading to reduced suppression

A
  • chemo
  • poor academic performance
  • “auditory listening problems”
  • ANSD
  • autism
35
Q

factors in adults leading to reduced suppression

A
  • unilateral acoustic tumors
  • migraine
  • tinnitus
36
Q

risk factors for HL as per joint committee on infant hearing screening

A
  • family Hx
  • infection associated with HL
  • bacterial meningitis
  • craniofacial anomalies
  • low birth weight (3lbs 5 oz)
  • hyperbilirubinemia (requiring exchange transfusion)
  • asphyxia (APGAR 0-3 at five minutes)
  • NICU stay for more than 48 hours
37
Q

4 reasons why OAEs are helpful in hearing screening

A
  • robust
  • linked to low thresholds
  • quick to obtain
  • noninvasive
38
Q

standard TEOAE protocol

A
  • 20 ms recording window
  • click rate of 50/sec
  • click stimulus
39
Q

QuickScreen protocol TEOAE

A
  • 12.5 msec recording window
  • click rate of 80/sec
  • stimulus: click
40
Q

normal TEOAE amplitude for infants

A

20 dB SPL +/- 5 dB

41
Q

normal TEOAE amplitude for adults

A

12 dB SPL +/- 5 dB

42
Q

most common ratio of f1/F2 in DPs

A

1.2 for infants, children, and adults

43
Q

difference in DP amplitude and noise between adults and infants

A
  • babies amplitude is 10 dB larger across frequencies

* below 3000 Hz is more noise in infants by 5-15 dB

44
Q

difference in OAEs between preterm and full term babies

A
  • TE and DP of preterm is lower than full term in amplitude
  • still higher than adults
  • increased levels as gestational age increased
45
Q

factors affecting OAE fail rate in babies

A
  • different pass criteria
  • number of attempts before leaving hospital
  • nursery type (NICU vs WBN)
  • age at screening (in hours/days)
  • software parameters (protocol used)
46
Q

two common types of middle ear dysfunction in infants

A
  • vernix caseosa in the ear-canal, can be fully occluding

* amniotic fluid which can stay in the middle ear for up to 24 hours after birth

AUD fall 2019 electrophys I (11 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions