Acoustic Immittance Flashcards
Acoustic immittance tests:
middle-ear function
Does acoustic immittance require a response from the patient?
No.
Acoustic immittance measurements help us to differentiate different types of _____________ disorders
Conductive
What can acoustic immittance identify?
A medically significant middle ear disorder that can be present without an air-bone gap evident in the audiogram
(T/F) Acoustic immittance measurements can be obtained during other tests.
FALSE. Acoustic immittance measurements yield information that cannot be obtained any other way.
What information does acoustic immittance tests provide?
Eardrum and middle ear problems
Differentiates type of disorder: conductive vs. cochlear vs. retrocochlear
Conformation of the pure tone audiometric results in terms of the type of less and an estimate of hearing sensitivity
Integrity of the facial nerve on the efferent pathway of the acoustic reflex arc.
What test is performed for acoustic immittance?
Tympanometry
What three acoustic reflexes are tested in acoustic immittance?
Ipsilateral
Contralateral
Reflex Decay
a term that refers collectively to acoustic impedance, acoustic admittance, or both
Acoustic immittance
The opposition to sound flow measured in acoustic ohm (obstruction to the flow - restricting)
Acoustic impedance
The easy with which sound flows measured in acousic mmhos (no opposition to flow - not restricting)
Acoustic admittance
Impedance and admittance are __________ terms.
reciprocal
What is the term for acoustic admittance measures
Ya (Y sub a)
What are the four tubes and what do they do in a tympanogram?
- Probe tip loudspeaker - presents a continuous tone (226 Hz at 85 dB SLP)
- Monitor Microphone - picks up reflected sound in the ear canal
- Pressure pump and manometer - pressure variation
- Ipsilateral reflex loudspeaker
Involves measuring the acoustic admittance of the ear with various amount of air pressure in the ear canal
Tympanometry/Tympanogram
Acoustic admittance is measured and plotted on a graph called a ________________.
tympanogram
What happens during a tympanogram?
A hermetic (airtight) seal is created at the opening of the ear canal by inserting an ‘ear plug’ into the opening of the ear canal
A tone of 226 Hz is generated by the loudspeaker
Air pressure is varied by the air pump
Reflection of sound is picked up by the microphone
The pressure within the ear canal is reduced below atmospheric pressure and a low-frequency tone is presented at 85 dB SPL continually
What are the five calculations that can be made from a tympanogram?
- Peak Ya - measurement plane tympanogram
- Peak Ytm - peak compensated static acoustic admittance (mmhos); compensated tympanogram
- TPP - tympanometric peak pressure (daPa)
- TW - tympanometric width (daPa)
- Vea/Vec/ECV - ear canal volume in cm^3
the total acoustic admittance (mmhos) at the peak
Peak Ya
(T/F) at the extreme high and low pressure levels, the Peak Ya is at zero.
False. It is not at zero because the ear canal itself offers a small degree of acoustic admittance
the contribution of the tympanic membrane alone
Peak Ytm
What is the unit of measurement for acoustic impedance?
acoustic ohm
What is the unit of measurement for acoustic admittance?
acoustic mmhos
In a tympanogram, which tube deals with pressure variation?
Pressure pump and manometer
In a tympanogram, which tube deals with picking up reflected sound in the ear canal?
Monitor microphone
In a tympanogram, which tube presents a continuous tone at 226 Hz, 85 dB SPL?
Probe tip loudspeaker
What is the formula for Ytm?
Ytm = Ya(peak) - Ya(tail)
The pressure at which Ya or Ytm is at its maximum value in daPa
TPP (tympanometric peak pressure)
the width of the tympanogram at 1/2 the high of Ytm (peak to tail)
TW (tympanometric width)
an acoustic estimate of the volume between the probe tip and the tympanic membrane - estimated from Ta at high or low pressure levels
Vea/Vec/ECV - ear canal volume
Large ear canal = _______ volume
High
Small ear canal = _________ volume
Low
What are the normal ear canal measurements for children (3-10)?
Peak Ytm - .25-1.05
TW - 80-159
Vea - .3-.9
What are the normal ear canal measurements for adults (>18)?
Peak Ytm - .30-1.70
TW - 51-114
Vea - .9-2.0
In a stiff ear, there is _________ admittance, ________ impedance.
low admittance
high impedance
If there is negative middle-ear pressure, the result is _________ admittance, ________ impedance.
low admittance
high impedance
If you have otitis media, you have _________ admittance, ________ impedance.
low admittance
high impedance
(it’s filled up with fluid)
If you have pressure equalization (PE) tubes, the result is _________ admittance, ________ impedance.
high admittance
low impedance
If there is a foreign object in the ear, the result is _________ admittance, ________ impedance.
- normal or flat tympanogram
- in some cases, you would not perform the test
If there is perforation of the TM or PE tubes, the ear canal volume will be ___________
abnormally large
If there is a probe tube up against the wall of the ear canal, ear canal volume will be ________
abnormally small
If you have otitis media limits with fluid, ear canal volume will be _________
within normal
What are acoustic reflex measures?
a time-locked (time-locked to the presentation of the sound) contraction of the stapedius muscle in response to an acoustic signal of sufficient intensity level and duration; always at suprathreshold levels
(T/F) The stapedius muscle doesn’t contract to soft sounds.
True
When the stapedius muscle contracts is pulls the stapes _____ and ____ of the oval window and ___ the ossicular chain, which in turn, reduces the acoustic admittance at the TM by a measurable amount (otherwise it would be transmitted to the ear with no change and it would be a very loud sound)
pulls the stapes down and out of the oval window and stiffens the ossicular chain
The acoustic reflex unilateral/bilateral.
bilateral
The _______ is not part of the acoustic reflex arc. It contracts with swallowing, chewing, etc.
Tensor tympani
The tensor tympani is a _______ muscle, with a _______ effect.
Large muscle with a small effect
The stapedius muscle is a _______ muscle, with a _______ effect.
small muscle with a huge effect
What is the normal pathway in which the acoustic reflex arc pathway travels?
Signal enters the (r/l) ear –>
travels through the outer, middle, and inner ear –>
along the VIII nerve, to the brainstem –>
cochlear nucleus in the brainstem –>
Right and left superior olivary complex and right and left facial nerve (VII) nuclei –>
to both facial nerves (VII) –>
contraction of both of the stapedius muscles.
Both stapes bones are pulled outward and downward in a direction away from the inner ear. This increases the impedance/decreases the admittance of the middle ear
When a loud sound enters the normal human ear, the stapedius muscle contracts on ______ sides regardless of which ear is receiving the stimulus.
BOTH
the level at which the first response is noted to the loud stimulus (activator signal); this is always at suprathreshold levels (70 dB to 100 dB HL)
acoustic reflex threshold (ART)
The acoustic reflex threshold tests the integrity of the _______
brainstem
if the stimulus and the measurement is recorded in the same ear
Ipsilateral response
if the stimulus and the measurement is recorded in the opposite ear
Contralateral response
In an acoustic reflex threshold, the ANSI specifies that the test ear (reference ear) is the one _____________.
receiving the stimulus
The acoustic reflex threshold will be affected once the damage to the cochlea has reached a certain degree - up to ___ dB HL
50 dB HL
Clinician Acoustic Reflex measures:
- Presence or absence of the acoustic reflex (ipsilateral or contralateral)
- Acoustic reflex threshold
- Acoustic reflex decay
the level of the activator signal producing the smallest measurable change in acoustic admittance
The acoustic reflex threshold
the amount by which the reflex amplitude (Ya) has decreased after 5 seconds for signals of 500 or 1000 Hz (only reliable at these two frequencies)
Acoustic reflex decay
Acoustic Reflex Decay is tested at the signals of _____ or _____ because ________________
500 or 1000 Hz; because it’s only reliable at these two frequencies
Abnormal reflex decay is a decrease in amplitude of _____ or more in ___ seconds or less.
50% or more in 5 seconds or less
Acoustic immittance should be used as a part of a _________
battery of tests
Acoustic immittance measurements (do/do not) measure hearing sensitivity
Do not
Acoustic immittance measurements can _______ the findings of ‘traditional’ hearing measurements
substantiate
When testing babies, a probe tone of ____ Hz is not recommended. _____ Hz is.
226; 1000
Combined used of contralateral ARTs tells you about some _______________
neural integrity
What are acoustic reflex measures?
a time-locked (time-locked to the presentation of the sound) contraction of the stapedius muscle in response to an acoustic signal of sufficient intensity level and duration; always at suprathreshold levels
(T/F) The stapedius muscle doesn’t contract to soft sounds.
True
When the stapedius muscle contracts is pulls the stapes _____ and ____ of the oval window and ___ the ossicular chain, which in turn, reduces the acoustic admittance at the TM by a measurable amount (otherwise it would be transmitted to the ear with no change and it would be a very loud sound)
pulls the stapes down and out of the oval window and stiffens the ossicular chain
The acoustic reflex unilateral/bilateral.
bilateral
The _______ is not part of the acoustic reflex arc. It contracts with swallowing, chewing, etc.
Tensor tympani
The tensor tympani is a _______ muscle, with a _______ effect.
Large muscle with a small effect
The stapedius muscle is a _______ muscle, with a _______ effect.
small muscle with a huge effect
What is the normal pathway in which the acoustic reflex arc pathway travels?
Signal enters the (r/l) ear –>
travels through the outer, middle, and inner ear –>
along the VIII nerve, to the brainstem –>
cochlear nucleus in the brainstem –>
Right and left superior olivary complex and right and left facial nerve (VII) nuclei –>
to both facial nerves (VII) –>
contraction of both of the stapedius muscles.
Both stapes bones are pulled outward and downward in a direction away from the inner ear. This increases the impedance/decreases the admittance of the middle ear
When a loud sound enters the normal human ear, the stapedius muscle contracts on ______ sides regardless of which ear is receiving the stimulus.
BOTH
the level at which the first response is noted to the loud stimulus (activator signal); this is always at suprathreshold levels (70 dB to 100 dB HL)
acoustic reflex threshold (ART)
The acoustic reflex threshold tests the integrity of the _______
brainstem
if the stimulus and the measurement is recorded in the same ear
Ipsilateral response
if the stimulus and the measurement is recorded in the opposite ear
Contralateral response
In an acoustic reflex threshold, the ANSI specifies that the test ear (reference ear) is the one _____________.
receiving the stimulus
The acoustic reflex threshold will be affected once the damage to the cochlea has reached a certain degree - up to ___ dB HL
50 dB HL
Clinician Acoustic Reflex measures:
- Presence or absence of the acoustic reflex (ipsilateral or contralateral)
- Acoustic reflex threshold
- Acoustic reflex decay
the level of the activator signal producing the smallest measurable change in acoustic admittance
The acoustic reflex threshold
the amount by which the reflex amplitude (Ya) has decreased after 5 seconds for signals of 500 or 1000 Hz (only reliable at these two frequencies)
Acoustic reflex decay
Acoustic Reflex Decay is tested at the signals of _____ or _____ because ________________
500 or 1000 Hz; because it’s only reliable at these two frequencies
Abnormal reflex decay is a decrease in amplitude of _____ or more in ___ seconds or less.
50% or more in 5 seconds or less
Acoustic immittance should be used as a part of a _________
battery of tests
Acoustic immittance measurements (do/do not) measure hearing sensitivity
Do not
Acoustic immittance measurements can _______ the findings of ‘traditional’ hearing measurements
substantiate
When testing babies, a probe tone of ____ Hz is not recommended. _____ Hz is.
226; 1000
Combined used of contralateral ARTs tells you about some _______________
neural integrity
