Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

AUDE 5410 Aud-Vestib Disorders > Quiz 3 (ANSD) > Flashcards

Quiz 3 (ANSD) Flashcards

1
Q

what is ANSD

A

disruption of neural synchrony

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

define ANSD

A

characterized by disruption to temporal coding of acoustic signals in the auditory n causing impairment of auditory perceptions relying in temporal cues

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

the phenotype of ANSD reults from

A

selective loss/damage of synaptic junctions of IHCs
NT release disorder by IHC synapses
injury to spiral ganglion
demyelinatioin/damage to myelin sheath, cell body or axon of CN VIII → can spread to BS
auditory n hypoplasia/absence

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

improve sound detection

A

OHCs

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

what is present in ANSD

A

pre-neural & cochlear OHC
in tact OAEs
CM

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

why are OAEs in tact with ANSD

A

because OAEs relate to OHC fxn and these are in tact with ANSD but they may disappear in later stages

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

what creates cochlear microphonics

A

OHCs

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

temporal resolution is not affected in ansd but frequency resolution is

A

false
temporal resolution is affect & frequency res is not

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

what do ABR results look like in ANSD

A

absent or abnormal
becauase ABR is generated by neural structures → neural integrity of 8th n & lower BS pathways are affected

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

ECochG and ARTs also are absent because of

A

CN VIII N involvement

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

critical for sound discrimination

A

IHC

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

what are ribbon synapses

A

highly specialized, encode sound w/ sub-millisecond temporal precision, mediated by calcium channels
vesicles that contain NTs

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

synapse w/ VIII N fibers

A

IHCs

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

DFNB9 & its relation to ANSD

A

AR
deafness gene that results in mutation in OTOF gene

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

what does OTOF gene do

A

encodes for protein otoferlin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

why is otoferlin important

A

calcium sensor for vesicle fusion & pool replenishment at IHC ribbon synapses

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

what is research showing with mic.e without otoferlin

A

they are profoundly deaf because sound evoked NT fails to release at IHC synapse even with normal sensory epithelium structure of the IHC

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

site of lesion of ANSD

A

spectrum disorder due to multiple sites of lesions

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

what is auditory/cochlear synaptopathy

A

loss of synchrony of neural firing causing loss of temporal resolution
could be at dorsal cochlear nucleus because of synaptic damage at IHC and/or at level of spiral ganglion
adversely affects fine speech structure decoding & speech perception especially in noise
also seen in ANSD

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Majority of NICU babies had a _____ hearing loss but ~ 20% had a ______ hearing loss

A

bilateral, unilateral

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

what is etiology of ANSD

A

idiopathic, genetic, or environmental

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

sound audibility & auditory perception are different. What does this mean

A

children w/ ANSD present w/ common pattern of electrophysiologic & electroacoustic results BUT auditory capabilities can vary vastly

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

PT population is heterogeneous for

A

etiology, presentation & management outcomes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Sensory IHCs & CN VIII N fibers in tact with this condition

A

DFNB9

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
nosology for ANSD
auditory neuropathy presynaptic & postsynaptic n disorder auditory neuropathy/dys-synchrony auditory synaptopathy more recently → cochlear synaptopathy or hidden hearing loss
26
incidence of ANSD
10-15% of deaf population more babies in nicu Majority of NICU babies had a bilateral hearing loss but ~ 20% had a unilateral hearing loss
27
etiology of ANSD
idiopathic genetic or environmental
28
what are genetic based ANSD's
non syndromic syndromic mitochondrial
29
non syndromic genetic ANSD
AR → mutations of Connexin 26 & Otoferlin (DFNB9) otoferlin is localized to IHC & often with synapse of IHC to VIII N fibers
30
syndromic genetic ANSD
associated w/ peripheral neuropathies Charcot Marie Tooth & Friedrich’s ataxia
31
mitochondrial genetic ANSD
comes from mom 100% (all m and f affected) will males transmit the gene? no because they shed their cytoplasm that contains the mitochondria Leber’s hereditary optic neuropathy
32
immune disorders deafness typical to ANSD
Guillian-Barre syndrome affects proximal nerve roots & portions of VIII N deafness & paralysis w/ lengthy recovery period
33
metabolic disorders & ANSD
diabetic neuropathy → typically acquired in adults
34
environmental based ANSD
viral infections
35
if VIII N primarily affect for any reason, clinical picture is
ANSD
36
if arterial supply unaffected,
OAEs CM & sometimes wave 1 of ABR can be identified
37
if arterial supply affected,
both neural & cochlear receptor elements are disrupted OHCs affected & OAEs & ABR may be absent which confuses clinical picture of ANSD
38
what are peripheral neuropathies?
Charcot Marie Tooth & Friedreich's ataxia
39
audiologic findings (summary)
present OAEs for most unless cochlear blood supply is compromised ABS ABR w/ present CM → confirmed w/ 2 polarity click stimulus at 70-90 dB nHL Abnormal ARTs → also present with any test of CN VIII fxn poor WRS in noise audio can have varying severity & configuration → not a measure of neural dys-synchrony PT vary in characteristics & management needs some benefit with amp some with CI’s some with neither
40
what do OAEs show for ANSD
they are tests of cochlear hair cell fxn can use TEOAE & DPOASE present in early years of ANSD and can become absent when OHC blood supply is compromised
41
what does contralateral OAE suppression show
normally shows decrease in OAE amplitude when masking is in the contra ear in ANSD, the involvement of efferent VIII N fibers doesn't let the neural impulses reach the OHCs creating no suppresison = abnormal
42
what is a click evoked abr
test of auditory nerve function ABR & CM
43
what normally happens with intensity and latency in ABR
as intensity decreases, intensity increases amp also decreases
44
what is seen with ABR in ANSD
latency of wave 5 doesn't increase ansd mimics a true abr present CM no amplitude decrease of waves I, II, V
45
waht should be done with ABR once you identify ANSD
stop the abr becuase it is useless
46
what are risk factors for ANSD
premature & low birth weight prolonged NICU stay O2 deficiency seizures hyperbilirubinemia
47
why does hyperbilirubinemia raise the question how long ABR status should be monitored and when CI should be considered?
because in few cases of it with transient ANSD spontaneous improvement can occur within first 2 years of life but they do not know if neural synchrony at the brainstem level restores and results in normal auditory processing so they typically wait 2 years before considering CIs
48
describe hyperbilirubinemia in terms of ANSD
may be reversible & spontaneously improve w/in 2 yrs of life primary site of lesion is NOT VIII N → damage in CANS & BS (primarily Cochlear nucleus) and descends to VIII N bilirubin accumulates in auditory BS & VIII n ganglion cells nerve death or dysfunction will occur but IHC unaffected
49
what tests will be abnormal with ANSD
any test involving 8th nerve word, reflexes, echog, contralateral suppression w/ OAEs
50
what is the site of lesion for ANSD
synapse bw 8th nerve & IHC, 8th nerve, spiral ganglion?
51
what are used to diagnose ANSD
careful case history OAEs ABR MEAR behavioral assessment speech audiometry ECochG vestib assessment if needed questionnaires for young children
52
describe OAE findings with ANSD
present because it is test of OHC fxn which is peripheral to 8th n can be absent later with compromised blood supply Contralateral OAE suppression (a normal phenomenon) is absent because the signal has to cross to the other ear, which can’t happen if we have nerve damage in the efferent nerve system
53
describe ABR findings in ansd
performed at high level click stimulus (70-90 dB nHL) w/ 2 polarities - NO ALTERNATING) CM reverses w/ polarity change, no latency increase with intensity decrease = ANSD
54
combo of what is essential for ANSD diagnosis
OAE & ABR w/ 2 polarities
55
why should alternating polarities not be used in suspected cases of ANSD?
Because it is the sum of condensation & rarefaction polarities so it will not show response reversal
56
what if CM is not present even with ANSD presence
due to clinician error or alternating polarity was used
57
describe MEAR findings in ansd
abnormal or absent even with normal/mild SNHL (we expect reflexes even with SNHL up to 60 dB HL)
58
why is MEAR absent with ANSD
reflexes require functioning 8th nerve so if it is affected reflexes will not happen
59
why do we use behavioral assessment with ANSD
because abr cannot be performed
60
describe behavioral assesment findings in ANSD
hearing sensitivity ranges from normal/mild to severe to profound SNHL w/ varying configurations unilateral or bilateral ~ 30 to 40% show a rising configuration hearing loss fluctuations in hearing can occur
61
can the audio tell us about ANSD
NO it doesn't give us anything about dys-synchrony
62
describe speech audiometry results in ANSD
significant impact no matter hearing thresholds due to IHC & CN VIII involvement some may be functionally deaf & some may have some intact intelligibility in quiet but poor in noise
63
what is recommended with speech audiometry? why?
SPEECH IN NOISE poor word rec scores worse in noise because there is neural involvement
64
describe echog findings with ANSD
abnormal becuase APs generate at VIII N which are affected
65
what if you didn't do two polarities? can you still pick up ANSD?
yes because as intensity decreases latency should increase so if wave 5 only exists and it stays the same, indicative of ANSD
66
ANSD is a continuum/spectrum
true
67
how is ANSD a spectrum
some can have no auditory complaints others can do poor in noise & MEMRs are absent, inconsistent auditory responses or some can have total lack of sound awareness
68
what other assessments can be done with ANSD
otologic eval with imaging of cochlea & auditory n genetic eal ophthalmologic if perifpheral neuropathies neurologic eval communication assessment
69
what is important to keep in mind with ANSD & management
variable auditory capabilities question is not how severe the HL is but how severe the dys-synchrony is
70
when are CI's successful
when pathophysicology is either biochemical abnormality of NT substances or synaptic deficits bw IHC & auditory n
71
when are CI's sometime successful
if neural integrity is compromised → loss of myelin, loss of neural elements (including VIII N)
72
how can ANSD be managed educationally
with auditory and visual stimulation manual communication like cued speech or ASL a formal education to facilitate literacy & self-dependence
73
how can ANSD be managed
HAs & FM systems trials most successful is CI's gene therapy
74
how does gene therapy help ANSD
adeno-associated virus (AAV) carries version of human OTOF gene used to introduce gene back into the innner ear through surgery deaf children reported hearing sounds & understanding speech

AUDE 5410 Aud-Vestib Disorders (18 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions