Mike's review Flashcards
(106 cards)
SPOT testing:
- Where are the electrodes placed?
- What are the settings for initial noise measurement?
- What are acceptable noise levels?
- ipsilateral mastoid on the implant side (red)
contralateral mastoid (green)
ground electrode on the forehead (black) - 500,000 samples/second
8 us acquisition rate
50 dB gain - +/- 0.05 V
SPOT testing:
- What are the settings for amplitude and pulse width growth test?
- What are the settings for ramp up?
- 500,000 sample/sec
8 us duration
20 dB gain - 20,000 Samples/sec
5,000 us duration
20 dB gain
- What is the normal charge voltage range in capacitor testing?
- If the charge voltage is out of range, what can we say about the leakage current?
- What leakage values are expected?
- 1.0-3.5 V
- The leakage values may not be valid. They are only valid if the charge voltage is within range.
- 50 uA
What would be good settings for a noise program?
A music program?/
Noise:
- narrow IDR to 45
- decrease low frequency gain/increase high frequency gains
- change filter to standard
- decrease sensitivity to 5 dB
- T-mic only mixing ratio
Music:
- extend low frequency filters
- increase IDR to 80 dB
- flatten gains
- disable AGC
- use Fidelity 120 strategy
- Aux input adjustment as needed
What are the disadvantages for ball electrodes?
What are the advantages to plate/planar electrodes?
Ball electrode:
- electrical current is spread in all directions
- increased chance of FNS
- higher current requirements
Plate electrode:
- all electrodes are directed towards the modiolus
- better capability to direct current
- more surface area which allow more charge without exceeding FDA limits
- spread is minimized with silastic partitions
NRI
- How far away is the recording electrode from the stimulating?
- can you stimulate and record from the same electrode?
- What coupling is used with NRI? Where are the grounds?
SW defaults to 2 apical for recording electrodes.
Example: if stimulating on e6, then recording will be e4.
- No, the stimulus artifact is too large
- Monoploar coupling. The stimulating electrode is grounded in the case. Recording electrode is grounded in the ring band.
What can be done to reduce noise during NRI?
increase number of averages
use a different recording electrode
use a PSP
increase gain (be careful of amplifier saturation) .
- What does electrode conditioning do?
- When does conditioning stop?
- What is the stimulus for conditioning?
- Introduces stimulation to all electrode contacts to stabilize impedances prior to programming.
- stop running when impedance no longer changes by 10% or more.
min: 3x
max: 10x - 256 uA current
40 usec PW
bipolar coupling
- What can influence an ECAP?
- What stimulus waveform is used in NRI testing?
- What is the stimulus rate?
- -number of nerve fibers
- whether nerve are firing synchronously or not
- nerve fiber location with respect to the measuring electrode - -biphasic pulses with a PW of 32 usec. Long enough to produce a highly synchronous response, but shorter than the latency of the response.
- 30 Hz.
What are the advantages of the Hi-Focus electrode?
16 plate electrodes which point to the sprial ganglion
silastic partitions to direct current toward the nerve
slightly pre-curved
not ear specific
1.1 mm spacing between contacts
electrodes are labeled 1-16
- What is the latency of N1 and P2?
2. What is the amplitude response size of the ECAP?
- 0.2 to 0.5 us and just before 1 us
2. 20-1500 uV
What is APW?
automatic pulse width: automatically optimizes PW and rate during device fitting process to maintain the narrowest PW and fastest rate for a given M level.
What are the advantages of the CII/90K ICS over the C1?
83,0000 pulses/sec
16 high precision output circuits
Fidelity 120, HiRes, MPS, CIS strategies
NRI
backwards compatible
- When should a manual PW be used?
2. When increasing to a manual PW, where should you start?
- poor sound quality
- inadequate growth of loudness due to FNS
- reports of sound flutters/choppy sound
- pt wants programs that are louder and louder - start with doubling the PW
What happens if compliance is exceeded?
- adequate loudness growth may not be achieved
- appropriate amplitude information may not be conveyed
- distortion may be introduced into the system
- patients are at an increased risk for somatosensory symptoms (FNS)
When should an electrode be turned off?
- impedance too high (open)
- unresolved FNS or somatic response
- inadequate growth of loudness
- pitch confusion
When was the S-series introduced?
1997
When was the 1.2 souind processor introduced?
1996
When was the 5th generation Harmony HiRes Bionic ear system introduced?
IOW: When was Harmony released?
2006
What year was the 1.2 ICS approved for adults and peds?
Adults: August 1996
Peds: December 1997
When was the 4th generation HiResolution system introduced?
2003
90K ICS
HiRes strategy
Auria sound processor
When was the CII Bionic ear system introduced?
April 2001
When was the C1 electrode postioning system approved by the FDA?
Adults: August 2000
Peds: December 2000
When was the enhanced bipolar electrode used?
1997-2000