Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

HESP712 > Cochlear Implant Programming > Flashcards

Cochlear Implant Programming Flashcards

1
Q

What is the dynamic range of hearing and its relationship to the MAP?

A
  • NH: ~120 dB
  • CI: up to 20 dB
  • Acoustic to electrical transformation is determined by the MAP
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Define MAPs.

A

-Configuration of current units (CUs), processing strategies, stimulation rate, etc.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Define programs.

A
  • Configuration of MAPs
  • Use of different programs
  • May be progressive over first to increase current levels
  • Similar to heading aid programs after first week/month (i.e., noise, school)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What would warrant an interim mapping appointment?

A
  • Changes in auditory discrimination
  • Increased request repetition
  • Addition/omission of syllables
  • Prolongation of vowels
  • Changes in vocal quality
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is most likely to warrant an interim mapping appointment for a child?

A
  • Prolongation of vowels

- Changes in vocal quality

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What do you do to connect the equipment before programming?

A
  • Verify 4 components:
    1. Computerized processing unit (CPU)
    2. Implant
    3. Processor
    4. Patient
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

How do you prepare the equipment for programming?

A
  • Verify connection of components
  • Initialize processor
  • Condition electrode array
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Describe how to initialize the processor.

A
  • For AB only
  • Dictate in the software: which ear, how it’s being used (i.e., AD, AU, bimodal)
  • Only needs to be done initially
  • May need to reset processor (for Cochlear)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Describe how to condition the electrode array.

A
  • For AB only

- Send stimulation to all channels at the same time

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What measurements should be performed during programming?

A
  • Telemetry
  • Neural response assessment
  • T- levels
  • C- or M-levels
  • Speech strategies
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is telemetry?

A
  • Aka impedance
  • Confirms proper communication between the processor and the electrodes
  • Always performed
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is neural response assessment?

A
  • Electrophysiologic response from the nerve in response to electrode stimulation
  • Essentially an eABR
  • Useful for children who cannot give subjective measurements
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are speech encoding strategies?

A
  • Different methods of stimulation that can produce different perceptions from the patient
  • Method by which the implant translates the incoming acoustic signal into patterns of electrical pulses
  • Can be simultaneous and/or sequential
  • Provide spectral and envelope information
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is impedance?

A
  • Measure of the opposition to electrical current flow
  • Impedance = voltage/current
  • Reported in kOhms
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What can cause electrode impedance?

A
  • Fibrous tissue
  • Electrolytes
  • Macrophages
  • Proteins
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are the stimulus parameters of electrode impedance?

A
  • Current
  • Voltage
  • Stimulus width
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What should be checked when measuring impedances?

A
  • Do electrodes have normal impedances?
  • Have the impedances changed?
  • Impedance of deactivated electrodes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What could cause abnormally low impedance?

A

<1 kOhm

  • Short circuit = short electrodes
  • Likely to send stim across all channels (happens in pairs)
  • May be caused by wires touching
  • If the case, deactivate and never turn back on
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What could cause abnormally high impedance?

A

> 30 kOhms

  • Open circuit
  • Likely a single channel
  • May be caused by: air bubble, broken wire, electrodes in contact with air
  • Can recover over time, so want to keep trying them
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

How should high impedances be addressed?

A
  • May decrease with use or by increasing pulse width
  • Initially, open circuits may be due to air bubbles in the cochlea (re-measure after stimulation)
  • Short circuits will never be activated
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is the electrically evoked compound action potential (ECAP)?

A
  • Gross potential that reflects synchronous firing of a large # of electrically stimulated nVIII fibers
  • Want to instruct patient to try to tolerate sounds but let the Au.D. if it’s too uncomfortable (want to look for nVII stim)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is the utility of the ECAP?

A
  • Corresponds to wave I of the acoustic ABR

- Corresponds to upper limit of eDR (M or C)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

How is Auto NRT (Cochlear) measured?

A
  • Select # channels to run (3, 5, 9, or all–usually adults: ~5; kids: ~9)
  • Click measure
  • Watch measurements and patient reaction
  • Prepare to skip channels if patient reports discomfort
  • Software will move on to another channel if stimulation reaches compliance without achieving a response
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

How is Flex NRI (AB) measured?

A
  • Select channels to stimulate (3, 7, 11, 15–avoiding basal channels)
  • Recording channel is 2 apical from stim
  • Select level of ordering (low to high if patient is conscious; high to low if patient is sedated)
  • Set min and max stim levels (-100 to 250 uV)
  • Look for 3 repetitions of response per channel (can change levels while running, skip to next data point, skip to next electrode)
  • Creates EP Growth Function
  • tNRI corresponds to M-levels
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

How is NRI measured for MED-EL?

A

-It can’t be measured manually

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What is the clinical utility of NRT/NRI?

A
  • Relatively stable over time
  • Used with impedances to tell if change in performance if due to device function or neural responsiveness (i.e., integrity of internal device)
  • Establishing a baseline for monitoring (every 6-12 months)
  • Establishing appropriate programming levels
  • Assess pitch perception at activation (i.e., same vs. different, pitch quality)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What is the electrically evoked stapedial reflex threshold (ESRT)?

A
  • Electrical stimulation to implant
  • Measure SRT in non-implanted ear (via immittance bridge)
  • SRT occurs at/near max levels used by speech processor
  • Not recorded in 25-35% CI patients
  • Requires some cooperation on the part of the patient
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

How is the ESRT measured?

A
  • Probe placed in contralateral ear
  • Continuously record acoustic admittance with 226 Hz probe tone
  • Present programming stimulus used for upper limit of DR (M-/C-levels)
  • Change in admittance occurs time-locked with stimulus when presentation level is of the ideal intensity for the upper limit of the DR
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What is stimulation mode?

A
  • Location of the reference electrode to the active electrode
  • Can be monopolar or bipolar
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What is monopolar stimulation mode?

A
  • Ground electrode is outside the cochlea
  • Wider spread for stim (problematic for strange anatomy)
  • Allows for lower thresholds (due to greater separation between ground and active)
  • Better battery life
  • More consistent thresholds for adjacent electrodes (can interpolar, don’t need to measure each)
31
Q

What is bipolar stimulation mode?

A
  • All stimulation occurs within the cochlea

- Better when there are concerns about spread of excitation

32
Q

What stimulation modes are available for the 3 manufacturere?

A
  • Cochlear and AB: either monopolar or bipolar

- MED-EL: monopolar mode only

33
Q

What is the input dynamic range (IDR)?

A
  • CI selects the range of intensities of input to code
  • What we try to mimic in CI output
  • Want a minimum DR of 30 or 60 CUs
  • Number of changes that happen to signals with CIs is significantly higher than with hearing aids (why brain/adaptation is so important)
34
Q

What are threshold levels (T-levels)?

A
  • Ensure that speech sounds are audible
  • Soundfield responses to NBN should be in line with specs ( 20-25 dB for Cochlear, 30-35 dB for MED-EL & AB)
  • If ~10 dB HL, too much stimulation (need to lower T’s to reduce stimulation)
35
Q

What would happen if T’s are too high?

A
  • Patient might be able to hear the processor
  • Turn off mic and see if noise goes away
  • If yes, then lower T’s
  • Want to ask what kinds of sounds are too loud
36
Q

What would happen if T’s are too low?

A
  • Patient can’t detect soft sounds (i.e. LING sounds)

- If yes, then raise T’s

37
Q

How are T-levels established for Cochlear?

A
  • Measured manually
  • Set at or just above threshold
  • Can be obtained via: ascending, bracketing, loudness growth chart
38
Q

How are T-levels established for AB & MED-EL?

A
  • Interpolated based on M-levels

- Highest stim where no sound is perceived

39
Q

What is a t-tail?

A
  • Doesn’t decrease in perceived level by patient but different in programming level
  • Want to set at highest stim level
40
Q

How should T-levels be measured in pediatrics?

A
  • May use with objective offset programming method (want threshold in at least 1 channel to see DR, then can apply DR to rest of MAP)
  • Can measure behaviorally via BOA, VRA, CPA in office or soundbooth (but with stim as stimulus)
41
Q

What are some considerations for setting T-levels in tinnitus patients?

A
  • Presence of tinnitus causes difficulties detecting stimulus during measurement (need to move quickly because there is no ambient noise to mask tinnitus when implant is off)
  • Multiple presentations of stim can help in perception over tinnitus
42
Q

How should T-levels be set in tinnitus patients?

A
  • Set T’s over level of tinnitus and then decrease globally

- Loudness balancing at 50% over T’s

43
Q

What is the significance of T-levels?

A
  • Artificially raised T’s results in better performance (also preferred by participants)
  • Progressively louder T’s, effectively reducing the DR (very little difference in performance)
44
Q

What are comfort levels?

A
  • Upper limit of the DR
  • Cochlear: set below max comfort (due to summation across electrodes)
  • AB: most comfortable level
  • MED-EL: highest stim level at which sound is loud but comfortable
45
Q

How should M-levels be measured for AB?

A
  • Channels are grouped by 4
  • Want a flap MAP across all channels (can flatten by doing single-channel measurements)
  • Measure groups of 4 channels with speech bursts
  • Measure single channels with tone bursts
46
Q

How should M-levels be measured for MED-EL?

A
  • Want a flap MAP across all channels
  • EX: start with all even channels, then odds
  • EX: 6, 12, 4, 16 (alternate so no residual stim)
  • Measure M-levels with tone bursts
47
Q

What are methods of measuring C- and M-levels?

A
  • Ascending technique (w/ multiple presentations at each levels)
  • Loudness growth charts
48
Q

What are some programming methods?

A
  • Behavioral
  • Objective preset
  • Objective with behavioral offset
49
Q

What is objective preset programming?

A

-Take NRIs/NRTs and have programming may you a MAP from it

50
Q

What is objective w/ behavioral offset programming?

A

-Use objective preset for T’s and C’s/M’s and then do behavioral measurements on at least 1 channel

51
Q

What influences current levels?

A
  • Speech processing strategies
  • Bipolar vs. monopolar mode
  • Stimulation rates
  • Proximity of electrode array to modiolus
52
Q

What is the effect of stim rate on current levels?

A
  • As rate increases, level decreases

- But doesn’t preserve battery life

53
Q

What are compliance levels?

A
  • The amount of voltage allowed for each electrode

- Ran first thing on new or transfer patients

54
Q

What does it mean to be “out fo compliance”?

A
  • Maximum voltage available from the implant is not sufficient to generate the desired current level
  • No further perception of loudness growth
  • Increase pulse width or decrease stim rate
  • Will then need to redo entire MAP
55
Q

What are the consequences of being out of compliance?

A
  • Insufficient loudness growth, variable loudness, lack of loudness growth
  • Sound may be distorted
  • Poor battery life
  • Decreased performance in general
56
Q

What is Automatic Pulse Width (APW)?

A
  • AB
  • Optimizes PW and rate during programming
  • Designed to maintain the narrowest PW and fastest rate for a selected HiRes strategy
  • APW calculates and adjusts PW and rate based on compliance and M-level requirements
  • May help to determine which manufacturer to select for a patient
57
Q

What are the two versions of APW?

A
  • APW I: most narrow PW for fastest rates

- APW II: more compliance headroom to allow for fluctuating impedances (default)

58
Q

What patients may benefit from APW?

A
  • Patients whose body chemistry may change

- EX: transfusions, arthritis

59
Q

When should manual PW be used?

A
  • Poor sound quality
  • Cannot obtain adequate loudness due to nVII stim
  • Increase PW (decrease rate)
60
Q

What is radio frequency (RF) transmission?

A
  • CIs have no internal batteries
  • All power comes across the skin from the transmitter coil
  • Burden of power rests upon what power it receives from the SP
  • Many intermittencies and sound quality problems arise from issues that surround transmission of power (disturbances between external and internal devices)
61
Q

What contributes to successful RF transmission?

A
  • Flap thickness/thinness
  • RF power level in software
  • Transmitter cable length
  • Battery option
  • Compliance levels
  • C-levels
  • Rate/maxima
  • Listening environment/input level
62
Q

How does flap thickness impact RF transmission?

A
  • Thick/fat head = hard to transmit signal

- Thin skin = ex/internal device are too close together (touchy transmission)

63
Q

What is power optimization?

A
  • The need for power
  • Voltage and Power dictate the user’s power level
  • Can the battery type provide sufficient voltage to deliver requested amount of current?
  • System calculated how much power is consumed by the “worst-case condition” (i.e., ambient room noise >65 dB)
  • Measurement done for each MAP (but only on main processor)
64
Q

What is indicated by power optimization across the skin?

A
  • Sufficient voltage available to the implant to ensure all electrodes remain in compliance
  • Sufficient power (voltage and current) for the demands of the chosen MAP
65
Q

What is voltage impacted by?

A
  • Skin flap thickness
  • T’s and C’s (current levels)
  • Impedances
66
Q

As required voltage increases, battery life life decreases. How can this be addressed?

A
  • Decrease pulse rate

- Want to use automatic power as much as possible

67
Q

When should compliance and power status be checked?

A
  • New MAP
  • New SP
  • Reported intermittences
  • Poor battery life
  • Change in sound quality
  • Transfer patient
  • > 6 months since last visit
  • Lost/gained weight
  • Significant growth/shortening of hair
68
Q

How should problems with battery life be addressed?

A
  • Decrease rate/maxima if high stim levels or OOC conditions are not an issue
  • Increase PW
  • Move to body worn SP
69
Q

What are some live voice modifications?

A
  • Tilting
  • Increasing/decreasing levels on all channels
  • Gain
  • Frequency adjustments
70
Q

What are some options for noise reductions?

A
  • AGC autosensitivity
  • Adaptive directional range optimization (ADRO–Coclear)
  • BEAM: multi-microphone technology
71
Q

What is ADRO?

A
  • Cochlear

- Adjusts gain at each frequency band to optimize the signal

72
Q

What is loudness balancing?

A
  • Ensure equal loudness on all electrodes
  • Need to make sure the patient understands the tasks (must understand pitch vs. loudness)
  • Incorrect loudness balancing can be detrimental to performance
  • Not always necessary due to use of loudness charts (may be warranted if MAP looks funny/not balanced, or if patient is getting artifact with live voice)
  • Can be done via balancing or sweeping
73
Q

What is pitch ranking?

A
  • If the electrode array is rolled over on itself, pitch does not increase from low to high on sequential electrodes
  • Usually identified in post-op X-ray
  • Balance neighboring electrodes
  • Reorder channels
74
Q

Describe counseling re: patient controls.

A
  • Programs: microphone modes
  • Volumes: modifies C-levels
  • Sensitivity: distance of hearing

HESP712 (10 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions