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ENT Secrets > Chapter 33 - Hearing Evaluation > Flashcards

Chapter 33 - Hearing Evaluation Flashcards

1
Q

Which test measures ability to understand speech

A

discrimination test

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2
Q

Pure tone average

A

Air conduction at speech freq

500, 1000, 2000

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3
Q

Masking

A

simultaneous presentation of sound to non-test ear

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4
Q

Stenger test

A

r/o malingering when 20dB difference between ears
tone 10dB above threshold given to better ear
Simultaneous tone 10dB below threshold to poorer ear
Patient should respond if HL is genuine
Malingering patients will not respond: + test

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5
Q

What is Hertz?

A

cycles/second

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6
Q

Weber test: two questions

A

Where they hear it?

Is it louder in one ear or another?

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7
Q

Negative Rinne

A

Sound heard louder at mastoid, BC>AC, sign of CHL of at least 25 dB (some say 15-20)

If equal or louder at EAC, its a positive test (NL)

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8
Q

Schwabach’s tuning fork test

A

Place on pt mastoid until can’t hear
then place on the mastoid of someone with NL hearing
If they can hear it, report test as “diminished”, indicating SNHL

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9
Q

Frequency spectrum for normal hearing

A

Human ear: 20-20,000 Hz
Typical adult: 200-10,000 Hz
Speech: 400-5000 Hz
Audiometric test: 250-8000 Hz

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10
Q

Decibel

A

hearing: db HL
environment: db SPL (sound pressure level)
Logarithmic scale
0 dB HL is normal hearing across entire frequency spectrum (HL meaning hearing level)

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11
Q

Normal hearing at 125 Hz vs 1000 Hz vs 6000 Hz

A

125- 45 db SPL
1000- 7 dB SPL
6000- 16 dB SPL

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12
Q

Hearing loss thresholds and severity

A

25-40: Mild
40-60: Moderate
60-80: Severe
>80: Profound

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13
Q

Symbols on audiogram

A

Unmasked AC: X (L), O (R)
Masked AC: square, triangle
Unmasked bone conduction: open to my left/right
Masked bone cond: open to my left/right

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14
Q

What does threshold mean

A

Patient perceives sound stimulus 50% of the time at that dB

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15
Q

Fletcher’s average

A

Use two best of the pure tone average frequencies

For patients with precipitously sloping HL

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16
Q

Normal air-bone gap

A 
approximately equal (<10 dB difference)
SNHL does not have air bone gap >10dB
17
Q

Speech recognition threshold

A

lowest dB at which patient correctly identifies the word in 50% of the presentations

Should be within 7dB of PTA/Fletcher’s average

18
Q

Speech discrimination/recognition test

A

Present words at 40dB above SRT, or at pt most comfortable loudness
Percentage of words correctly identified (out of 25)
Good is 80-100%

Can do in presence of background nosie to estimate functional performance with and w/o HA/CI

19
Q

Immitance test battery

A

tympanometry

acoustic reflex measurements

20
Q

Tympanometry: how it works

A

compliance of TM maximum when pressures equal

Peak pressure = middle ear pressure, nL 0 to -150

21
Q

Tympanogram types

A

A- NL
As- stiffer (low compliance), otosclerosis
Ad- more flaccid (higher compliance), oss discont
B- flat, no pressure peak. Immobile. eff/perf
C- peak less than -150, ETD

22
Q

Differentiate type B effusion vs perf

A

look at ear canal volume
High = perf (included middle ear)
Normal vol in kids is 0.5-1cm^3, in adults up to 3

23
Q

Acoustic Reflex

A

Loud sound –> stapedius (b/l) and tensor tymp –> stiffen ossicles, DEC TM compliance
Stapedius: attach to posterior crus stapes, pulls stapes from oval window
TT: pull malleus in toward middle ear
Decreases loud sounds 20dB over threshold by 15dB
Decreases vocalization sound by 15dB

24
Q

Acoustic reflex neural pathway

A

cochlea –> CN VIII –> cochlear nucleus –> trapezoid body –> Sup Olive Complex –> CN VII nucleus –> stapedius m
Crossover at sup olive to contralateral cochlear nucleus for contralateral pathway and contraction of stapedius

25
Q

How is ABR conducted

A

Baby relaxed
Scalp electrodes for EEG
Clicks/tones through earphones –> evoke electrical potentials that are measured

26
Q

How to interpret ABR waves

A 
Mnemonic E COLI
I- Eighth CN
II- Cochlear nucleus
III- Olivary complex Sup
IV- Lateral lemniscus
V- Inf colliculus

Tumor delays waveform at site of lesion
Auditory neuropathy is absent Wave I

27
Q

Auditory Steady State Response

A

Can be louder than ABR, good for differentiating severe from profound HL
Frequency-specific tonal stimulus

28
Q

What do OAE’s measure?

A

sound produced by cochlea following acoustic stimulation
Do not measure neural function
Transient evoked and Distortion product

29
Q

Ways to tell if someone is feigning HL

A

For unilateral HL, sound should cross over somewhere between 40-70 dB and be detected in poor ear with AC
With BC, sound crosses over to poorer ear as its interaural attenuation is 0 dB
PTA-SRT/SAT should agree

ENT Secrets (79 decks)

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