Aud & Vestib Disorders Flashcards
(122 cards)
What is an ABR? What does it assess? What is one clinical app of it?
It is used to assess the neural auditory pathway. The ABR tests and assesses the electrical potentials generated by the auditory neural pathway and it is an electrophysiologic test called an auditory evoked potential. We clinically use waves 1, 3, and 5 and as intensity decreases latency increases.
To diagnose ANSD
To confirm results of behavioral tests & establish site of lesion
How do we know OAEs are a measure of OHC fxn? What are different stimuli used for TEOAE and DPOAE?
Absence or damage of OHCs is associated with absence of OAEs further supporting the hypothesis that OAEs are generated by OHCs
TEOAE: brief acoustic stimulus (click or tone burst)
DPOAE: Simultaneously presented pure-tones of two appropriate frequencies (fi & f2) presented at two intensity levels (L1 & L2)
2f1-f2 elicits the best DPOAEs in humans
Baby failed screening and the audiologist did ABR and diagnosed sensorineural HL. 3 months later had normal hearing and passed.
What could have been done to cross check the loss?
What could have been the cause of the fail?
OAEs
Neuromaturation
What disorder should you not use alternating clicks to determine?
ANSD
A decrease in intensity should also cause a decrease in latency
f
CM are produced by OHC
t
Actual hearing threshold is typically ~10 to 15 dB HL better than the ABR threshold
t
normative Peak Latency Values at 80dB nHL
Wave I: 1.5 ms (mean)
(SD = + 0.25 ms)
Wave II: 2.6 ms (mean)
(SD = + 0.25 ms)
Wave III: 3.7 ms (mean)
(SD = + 0.25 ms)
Wave IV: 4.7 ms (mean)
(SD = + 0.5 ms)
Wave V: 5.5 ms (mean)
(SD = + 0.5 ms)
Inter-peak values at ~80 dB nHL presentation level
I - III IPL: 2.25 ms
(SD = + 0.5 ms)
III - V IPL: 2.0 ms
(SD = + 0.5 ms)
I - V IPL: 4.0 ms
(SD = + 0.5 ms)
abr transducer
insert
abr stim
click, chirp, tone bursta
abr rate
> 20/s
90/s useful for neurodiagnosis
abr intensity
variable in db nHL
10-90 dB
Relationship BW latency and Intensity
As intensity decreases the latency of the waves (wave V) increases
As intensity decreases the morphology of the ABR response deteriorates
abr & CHL
absolute latencies are pushed out but relative interwave latencies were retained within normal limits
abr & SNHL
wave 1 is prolonged (~ 2 ms)
wave 5 has normal latency (~ 6 ms)
Latency-intensity function shows a wave V not repeatable at 45 dB nHL – a higher hearing threshold
retro path & abr (vestib schwan
diminished wave I and absent wave III & V
What is congenital aural atresia? What is a condition associated with it? What is the FDA approved device for it and at what age?
failure of canalization results in this
associated with microtia & ME anomalies
spontaneous, can occur with Treacher collins, trisomy 22, crouzon’s & hemifacial microsomia
BAHA, after age 5 years old
man with bilateral mixed HL from 500-4000 in the high frequencies. What could be the cause?
Collapsing canals
What is the external canal condition caused by radiation to the head and neck?
ORN
OSTEORADIONECROSIS
what are the signs of impacted cerumen?
Mild CHL
tymps <.02 ml
Coughing
Dizziness
All the above
all
What is not the sign of it?
Otalgia
Tymps >.03 ml?
Complaints of fullness
Mild CHL
Dizziness
Tymps >.03 ml?
most common viral infection
accompanies VII N paralysis
earliest symptoms = painful rash in ear canal, concha, or below/behind auricle
rash caused by virus localizing in skin & results in painful vesicular (blister) eruptions
herpes zoster oticus (shingles)/ramsay hunt syndrome
outward scar tissue growth
follows ear trauma, piercings, viral infections (like herpes)
can spread
keloid