Wk8-Clinical Aspects- Internal components and speech processors Flashcards Preview

F20-9527-Cochlear Implants > Wk8-Clinical Aspects- Internal components and speech processors > Flashcards

Flashcards in Wk8-Clinical Aspects- Internal components and speech processors Deck (26)
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1
Q

CIs are perhaps the world’s most successful medical prostheses. What determine’s that?

A

< 0.2% of recipients reject it or do not use it

The failure rate needing re-implantation is around 0.5%

2
Q

Describe the “Conceptualization” phase of CI development

A

1800-1949

  • Volta’s “jumper cable” experiment
  • Stevens et al identified 3 possible mechanisms underlying electric stimulation
3
Q

When was the first reported confirmation of the effectiveness of CIs?

A

In 1977, during the “Research and Development” phase (1950-1979)

4
Q

When was the “Commercialization” Phase?

A

1980-2008

5
Q

Not all CI’s use a ground electrode (like monopolar). What are the 2 alternatives?

A

Neighbouring electrode (bipolar) or plate electrode

6
Q

Though they differ in some ways based on manufacturer, what are 4 internal component similarities?

A
  • all have an antenna
  • all have a receiver/stimulator
  • all have electrode arrays
  • all have a magnet
7
Q

What are the most important differences between different manufacturer CI’s?

A
  • placement of reference electrodes
  • pre-curved vs straight arrays
  • removable vs non-removable magnet
  • orientation of electrodes
  • number of electrodes
  • length of electrode array
8
Q

One manufacturer offered 3 array options:

  • a standard array for deep insertion
  • a medium array for ____, ____, _____
  • and a ____ array, which is 2 electrodes for significantly ossified cases
  • a compressed array - shortened for Mondini or malformations
A
  • medium array for fibrosis, re-implantation, or special cases
  • split array
9
Q

How is the split array inserted?

A

The longer array is implanted in the basal portion of the cochlea, and the shorter array is inserted through a second opening into a more apical location for cochleas that are severely ossified

10
Q

CI arrays may vary by length, width, etc. What length might be considered for EAS?

A

24 mm or shorter

11
Q

The Form24 has a tapered silicon portion at the base of the array. What is it’s function?

A

To prevent CS Fluid leakage

12
Q

Why do we need so many lengths and types of electrodes?

A
  • Cochleas come in many lengths
  • most are 31 mm long, but vary from 25 m to 35 mm
  • on a cochlear MRI, the distance b/w the oval window and most lateral point of the cochlea is measured. Size of distance and type of approach can help us estimate correct electrode array.
13
Q

Why don’t we necessarily want as deep of a CI insertion as possible?

A
  • Some research has indicated that deeper insertion (past the “hearing zone” of the spiral ganglion cells) may not improve ability to hear low frequencies, and may lead to worse outcomes
  • deep insertion poses significant risk of cochlear damage
  • > recommended higher density of electrode contacts within the hearing zone = greater flexibility
14
Q

For a standard MRI, 1.5 tesla is enough, and most CI’s can withstand that with the magnet intact (and possibly a bandage to keep it in place). What happens with more detailed MRI’s, which may need 3 tesla?

A

The magnet must be removed during a day surgery the day before (only one manufacturer states a 3 tesla limit with the magnet in place (the Symphony))

15
Q

How can we ensure that the electrode is inserted properly?

A

We can’t do an MRI b/c of the magnets, so we do an x-ray

  • usually done right after surgery
  • can do video x-ray during insertion, but not really needed.
16
Q

Regardless of manufacturer, what should all on-ear processors have?

A
  • at least 1 microphone
  • a battery source
  • an accessory port
  • a cable
  • a coil (that connects to the processor; usually can come apart, but not always)

*When worn on the body, need to come with straps to hold it there

17
Q

What is the problem with body worn processors?

A

The mic location

  • head shadow
  • pinna effect
18
Q

Where is one manufacturer placing it’s microphones?

A

In the ear, at the end of the ear hook

- can take advantage of the pinna effect?

19
Q

What are the 3 types of batteries that CI speech processors can use?

A
  • IMPLANT 675
  • rechargeable
  • AAA (body worn processors)
20
Q

Are CI Speech processors waterproof?

A

Some are, and some need an accessory (watertight plastic)

21
Q

What types of accessories can be found with CI’s?

A
Wireless technology (FM systems, BT, TV streamers, etc) similar to those for hearing aids
*keep in mind, it varies based on manufacturer - some have chosen not to provide these
22
Q

Some CI speech processors use only one 675 battery instead of two, giving it a smaller appearance. What are the pros and cons?

A

Pros: smaller, so better for tiny ears (children)

Cons: shorter life and can’t plug in FM system b/c not enough power

23
Q

What are some of the wearing options regarding the speech processor for kids?

A

Babies: transmitter + body worn speech processor

Children: transmitter + BTE portion + body worn battery pack

  • transmitter + BTE portion + FM boot/receiver
  • small battery pack
24
Q

Besides BT, how can CI’s be connected?

A

Personal audio cable

TV HiFi

25
Q

What do we need to be careful of, regarding troubleshooting devices?

A

They only check the speech processor - we still don’t know how the electrode array is sending the signal/what’s being heard

26
Q

Who were EAS designed for?

A

People with a mild-to-mod SNHL in low frequencies and severe to profound loss in high frequencies