Chapter 33 - Hearing Evaluation Flashcards
Which test measures ability to understand speech
discrimination test
Pure tone average
Air conduction at speech freq
500, 1000, 2000
Masking
simultaneous presentation of sound to non-test ear
Stenger test
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
What is Hertz?
cycles/second
Weber test: two questions
Where they hear it?
Is it louder in one ear or another?
Negative Rinne
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)
Schwabach’s tuning fork test
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
Frequency spectrum for normal hearing
Human ear: 20-20,000 Hz
Typical adult: 200-10,000 Hz
Speech: 400-5000 Hz
Audiometric test: 250-8000 Hz
Decibel
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)
Normal hearing at 125 Hz vs 1000 Hz vs 6000 Hz
125- 45 db SPL
1000- 7 dB SPL
6000- 16 dB SPL
Hearing loss thresholds and severity
25-40: Mild
40-60: Moderate
60-80: Severe
>80: Profound
Symbols on audiogram
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
What does threshold mean
Patient perceives sound stimulus 50% of the time at that dB
Fletcher’s average
Use two best of the pure tone average frequencies
For patients with precipitously sloping HL