Immitance OCSE Flashcards
(14 cards)
How would you explain otoscopy and identify contraindications to the tympanometry test?
“Before we begin this test, I am just going to have a look in your ears to make sure everything is looking good. Have you had any type of middle ear surgery in the past 3 months? Or any recent grommet insertion? Great, everything is looking healthy”
Look for discharge, occluding wax, otitis externa
Contraindications: stapedectomy/stapedotomy or other middle ear surgery within the past 3 months, grommet insertion within past 6 weeks
How do you calibrate the tympanometer?
- Check the holes are clear of obstruction
- Perform cavity calibration
What are the acceptable cavity volumes?
0.2 cm3 = 0.1 – 0.3 cm3 (+/- 0.1cc)
0.5 cm3 = 0.4 – 0.6 cm3 (+/- 0.1cc)
2.0 cm3 = 1.9 – 2.1 cm3 (+/- 0.1cc)
5.0 cm3 = 4.75 – 5.25cm3 (+/- 0.25cc)
How would you explain the tympanometry test?
“The next test we are going to do is a test that will measure how well the sound is being transferred through your ear. What I am going to do is place this plug in your ear and play a low humming sound. You will feel a pressure change like you are going up in a plane or car. I don’t need you to do anything for this test, just sit as still as you can and try not to talk or swallow. Are you happy for me to complete this test? Did you have any questions before we start?”
How would you explain the reflex test?
“This next one will measure a reflex in your ear. In your ear there is a small muscle that contracts when I play a loud sound but to do this the sound has to travel through your ear and to your brainstem and back, so this test helps us to see how that pathway is working. This test does require me to play some loud sounds in your ear. Do you experience any tinnitus or discomfort with loud sounds? If it gets uncomfortably loud please let me know or raise your hand and we will stop the test. Again, all you need to do is sit as still as you can and try not to swallow. Are you happy for me to continue with this test?”
What is a process to complete the reflex test?
- Start with contralateral right (sound in right ear, probe in left ear)
- Choose starting level at 70-80 dB
- Make sure contra is selected
- Start/stop
- Stimulus button
- Go through frequencies: 500, 1000, 2000 (change with small triangle buttons at the bottom)
- Obtain a baseline: no reflex
- Obtain a reflex: >0.02ml
- Obtain a repeat: >0.02ml
- Obtain a growth: 5 dB above the reflex threshold
- Repeat for Ipsi
What are the characteristics of a type A tymp?
Peak Admittance
- Between (and including) 0.3 to 1.4
Peak Pressure
- Greater then or equal to -100 daPa
Canal Volume
- 0.6 - 1.5
What are the characteristics of a type Ad tymp?
Peak Admittance
- Greater than 1.4
Peak Pressure
- Greater then or equal to -100 daPa
Canal Volume
- 0.6 - 1.5
Causes: flaccid or hypermobile ear system, ossicular discontinuity
What are the characteristics of a type As tymp?
Peak Admittance
- Less than 0.3
Peak Pressure
- Greater then or equal to -100 daPa
Canal Volume
- 0.6 - 1.5
Causes: stiffness dominated (otoscelerosis, tympanosclerosis)
What are the characteristics of a type C tymp?
Peak Admittance
- Classified as deep or shallow if it falls outside the normal range
Peak Pressure
- <-100 daPa
Canal Volume
- 0.6 - 1.5
Causes: abnormally negative peak pressure, Eustachian tube dysfunction
What are the characteristics of a type B tymp?
Peak Admittance
- No clear peak
Peak Pressure
- n/a
Canal Volume
- n/a
What are the characteristics of a type Blow tymp?
Peak Admittance
- No clear peak
Peak Pressure
- n/a
Canal Volume
- <1.5
Causes: otitis media, occluding cerumen
What are the characteristics of a type Bhigh tymp?
Peak Admittance
- No clear peak
Peak Pressure
- n/a
Canal Volume
- > 1.5
Causes: Perforated ear drum, patent grommet
How much does a deflect need to be to be taken as threshold?
> 0.02ml
Time locked to the stimulus
Repeatable
