CH. 8 - Immittance Audiometry Flashcards
what is this?
immittance meter
general term encompassing impedance and admittance
Immittance
ease with which energy can flow in a vibratory system
Admittance
extent which system resists flow of energy through it
Impedance
Impedance meant to represent both ___ and ____
admittance; impedance
way of assessing manner in which energy flows through outer and middle ears to cochlea
Immittance audiometry
what triggers the acoustic reflex?
when a sound has sufficient intensity
Most common reason for abnormality of acoustic reflex is ___
middle ear disorder
what are three primary functions of immittance audiometry in relation to evals?
- Useful for detecting middle ear disorders
- Differentiating cochlear and retrocochlear
- Cross-check to pure tone
When using an immittance meter, you’ll use ___ Hz, unless you’re working with infants or newborns. Then you’ll use ___ Hz
226; 1K
What is the standard dB of immittance test?
85 dB
How does air pressure relate to acoustic admittance RE TM?
Best when pressure is equal on both sides
What does a tympanometry test measure?
how acoustic immittance of middle ear changes as air pressure varied in external ear canal
Four values that determine tympanogram type
-Static acoustic admittance
-Tympanometric width
-Equiv ear canal volume
-Tymp peak pressure
what does ECV stand for?
Ear canal volume
what does ear canal volume measure?
Estimate of volume of ear canal from tip of probe to TM
what is a normal ECV value?
0.5-1.5 cc
Graphing of tympanogram is called a ___
tracing
Type A tympanogram peaks at 0 daPa in an ideal case, but can also be considered type A if it peaks from ___ - ___ daPa
-100; 100
what type of tymp is this?
A
what type of tymp is this?
B
what type of tymp is this?
type C
what type of tymp is this?
aS
what type of tymp is this?
aD
a type A tymp indicates
normal middle ear function
a type B tymp indicates one of these two
1) mass added to ossicular chain, often from fluid
2) perforation in tympanic membrane
if someone has PE tubes in their ear, their tymp type should be __, ECV should be
B; large
why does type C happen?
Eustachian tube dysfunction, creates vacuum
in type aS tymp, what does the “s” stand for?
shallow
in type aD tymp, what does “d” stand for?
deep
On a tympanogram, the X value is ___ and the Y value is ___
TPP; SA
what does TPP stand for
tympanic peak pressure
what does SA stand for?
static admittance
what is TTP an estimate for?
air pressure in middle ear
when a sufficient intensity of sound is delivered to the right ear, the acoustic reflex should activate in the ___ ear
both
acoustic reflex tests can be _____ (same side) or ____ (opposite side)
ipsilateral; contralateral
most of the time, abnormal acoustic reflex is because of a problem here
middle ear
acoustic reflexes tested at these frequencies
500, 1K, 2K, 4K
acoustic reflex tests can help screen for __ ___ and __ , which often don’t have acoustic reflexes, even with normal hearing
auditory neuropathy; APD
