Lecture 3 Flashcards
(55 cards)
What number on a tymp shows it is type Ad?
Compliance/static admittance
A ____ volume size is a pretty good indicator of normal volume
2.0
Why is a 3.0 volume and type A tymp normal?
Because the peak shows that the TM is working fine (a hole would show a type b tymp)
What classification of tymps is most commonly used?
Jerger classification system
The normal frequency for a tympanogram is ____Hz and we measure the ____ component
226Hz, Y
Y = ____
Total admittance
But, you can run tymps up to ____Hz on some commercial machines
2000
The higher the frequency, ther harder it is to maintain ____
Constant SPL
MFC measures Y, but can extract ____ and ____ components from that measure
B, G
When do you use MFC tymps?
- unusual Y tymps (the conventional tympanogram)
- neonates
- severe mixed losses when its difficult to mask B/C results
- to estimate ME resonance frequency
- an indicator of cochlear involvement
What are some unusual Y tymps that may result in needing MFC tymps?
- type Ad (hyper-compliant tymps)
- normal tymps with A/B gaps
What do MFC tymps usually distinguish between?
- ossicular discontinuity
- monomeric/atrophic TMs (ME is still working okay, just a flaccid TM)
What are monomeric/atrophic TMs?
- The TMs consist of 3 layers (outer epithelial, medial mucosal, and inner fibrous)
- If you get a lot of ear tubes, the inner layer may not heal (the TM becomes more flaccid), but overall, the TM is not working good
What does this tympanogram indicate?
- regular Y tymp (type b)
- Large volume
- Either a perforation or an open tube
What does this tympanogram indicate?
- type As (flaccid component)
- no perforation, but still abnormal (static admittance is 4.4ml)
What is better for picking up cracks in ossicules? CT or MFC tymps?
Sometimes CT scans wont pick up a crack in the ossicles (abormal HF tymps pick up ossicular discontinuity more than CT)
What does the C mean in MFC tymps?
- multi-component
- various mechano-acoustic elements can be separated out from each other and recorded (susceptance and conductance)
What admittance element is associated with stiffness/springiness?
Compliant susceptance (Bc)
What admittance element is associated with mass?
Mass susceptance (Bm)
What admittance element is associated with friction?
Conductance (G)
Stiffness/springiness, mass, and friction = ____
Total admittance (Ya)
Why are mass and stiffness/springiness both under susceptance (B)?
- Mass and stiffness are both under B because the mass effects are depending on stiffness, and stiffness is dependent on how much mass there it
- When you change the mass, the stiffness effects change
- When you change the stiffness, the mass effects change
- With B, you can see which effect is dominant over the other
Conductance (G), is a function of ____ friction
Inner ear fluid
What is meniere’s disease?
Inner ear fluid and pressure problem (causes LF fluctuating HL, tinnitus, vertigo) – an inner ear fluid disorder
