Programming and Coding

Question 1

Telemetry

Answer 1

Confirms proper communication between the processor and the electrodes
AB and Cochlear:”impedance”
Medel: “telemetry”

Question 2

Neural response assessment

Answer 2

Electrophysiology response from nerve in response to electrode stim

Useful for pediatrics who can’t give subjective measurements

Question 3

T levels

Answer 3

Measures threshold for sound on each electrode (only cochlear devices)

Measures the lowest amount of electricity needed to be perceived as sound

Question 4

C or M levels

Answer 4

Comfort levels measured using a scale

-Upper loudness levels.

Question 5

Speech strategies

Answer 5

Different methods of stimulation that can produce diff perceptions from the patient

• sequential
• simultaneous
• both

Question 6

Connecting equipment

Answer 6

You’ll need:

• computerized processing unit/ interface (cpu/cui); the “pod” that allows the computer to communicate with the processor
• implant
• processor
• the patient

Question 7

Prepare equipment: AB

Answer 7

1. Verify connection of components: coil to cable to processor
2. Initialize processor
   - which ear, modality of use (bilateral, unilateral, bimodal)
   - do this when loading/reassigning a processor
3. Condition electrode array
   Stimulate all channels at the same time
   Gets rid of buildup around array
   Perform this at activation, 1wk follow-up, returning on channel

Question 8

Prepare equipment: Cochlear and medel

Answer 8

1. Verify connection of components: coil to cable to processor
2. Reset processor as needed

Question 9

Impedance

Answer 9

Stimulus parameters: current, voltage, stim. Width

Material of electrode surface: (an inverse relationship) narrower contact, more impedance

Nature of the medium of transmission is specific to each electrode: air vs tissue

Measures the opposition to electrical, current flow
Impedance (kiloOhms)=voltage/current

Voltage= impedance x current
When current is cons at increase in impedance will increase voltage

More resistance to flow = higher impedance

Question 10

Deactivated electrodes

Answer 10

Short electrodes (-<1kOhmn)

• wires touching and likely to send stim across channels
• always in pairs
• turn off and leave off forever

Abnormally high impedance (>30kOhmn)

• broken wire
• air bubble; current can’t travel through air—> remeasure post stimulation
• may decrease with use or by increasing the pulse width

Question 11

NRT

Answer 11

Neural Response Telemetry
-Cochlear specific
-use of the electrically evoked compound action potential
—gross potential that reflects synchronous firing of a large # of electrically stimulate n8 fibers
—-reflective of wave I of acoustic ABR and comfort levels or upper dynamic range

AB: Neural response imaging (NRI)

Question 12

Auto NRT

Answer 12

Cochlear Specific
Steps:
1. Select # of channels to run (3, 5,9) a low, mid and high. Running all will take a long time

2. Click measure
3. Watch measurements and pt reaction
4. Prepare to skip channels if pt. Reports discomfort
5. Software will move on to next channel if stimulation reaches compliance w/o achieving a response

Auditory neuropathy won’t have NRT
No need to measure later because they should be stable

Question 13

Terminology

Answer 13

Programming/mapping: Measuring thresholds, tolerance levels, assessing implant status

MAPs: configurations of current units (CU); processing strategies; stimulation rate

Programs: configurations of MAPs; similar of hearing aid programs;use of different programs

Question 14

Flex NRI

Answer 14

AB specific
NRI= Neural Response Imaging
1. Select channels to stimulate on (avoid most basal @ activation- build up)
2. Recording channel is 2 apical from stim
3. Select level of ordering
–low to high (awake pt.)
–high to low (sedated/surgery in OR)
4. Set min and max stim levels (100-250 uV)
-look for 3 repations of response per channel
5. Crates EP Growth FUnction (best regression line)
6. tNRI corresponds to M levels (not as nicelys to C levels for Cochlear)

NRI/NRT not in MedEl

Question 15

Clinical Utility of NRT/NRI

Answer 15

• Stable over time
• Used w/ impedances to see if change in performance is due to device function or neural responsiveness; Pt not doing well and impedances are weird, recheck this and if abnormal, may indicate a soft failure.
• Measure w/in first few months of stim (baseline)–> annually/bi-annually afterwords
• loosely correlates with Ms/Cs as a guide to max comfort levels
• Can assess pitch at activations “same vs diffierent” or high vs low

Question 16

Terminology per company

Answer 16

Cochlear:
Ts and Cs are required
AB/MedEL: Ts are optiona (will be interpolated from Ms) l and Ms are required

SF thresholds per compant
Cochlear: 20-25 (slight)
AB/M: 30-35 (mild)

Question 17

Challenges of NRT/NRI

Answer 17

Highly influenced by

• neural survival and synchronous activity
• nerve survival re: measuring electrode

To reduce noise

• remove contra CI
• Increase high level and # of averages (AB)
• decrease sample per data point

Question 18

ESRT

Answer 18

-electrically evoked spatial reflex thresholds

-Electrical stimulation to implant
Measure SRT in nonimplanted ear
—immittance bridge or in OR w/ bridge
-ESRT occurs at or near max levels used by processor
-Not recorded in 25-35% of patients **
-Pt.s participate to a degree

Question 19

How to perform ESRT

Answer 19

1. Place probe in contralateral ear
2. continuously record acoustic admittance w/ 226 Hz probe tone within Decay screen
3. Present programming stim used for upper limit of DR (C/M level)
4. Change in admittance occurs time locked with stimulus when presentation level is the ideal intsenity for the upper limit of the DR

Medel is the only one with ESRT screen

Must consider hx. of middle ear disorder

Question 20

Stimulation Mode

Answer 20

location of the reference electrode re: active electrode

Monopolar (ground is outside of the cochlea)
Bipolar (stim occurs w/in cochlea)

Cochlear and AB: either
Medel: monopoglar only

Question 21

DR

Answer 21

For speech (single)- 30 dB
multiple speakers >60 dB

NH: 100 dB
CI: 3-20 dB

distance between Ts and C

Input DR (IDR): CI select the range of intensities o output to code

Question 22

Threshold trouble shooting

Answer 22

T’s are too loud
-person hears motor noise of processor. Turn mics off and no longer hear, turn T’s down

Child w/ 5 dB to NBN: adjust T levels
Bring Ts up for better thresholds and lower Ts for poorer thresholds

Question 23

Threshold

Answer 23

Cochlear Nucleus: ser at a level at or just above threshold
“just barely detecting

Medel CIS: highest stim where no sound is perceived

T tail: audible over a given range–> set at upper limit of their range.

Question 24

T levels in Ped

Answer 24

May use with objective offset programming method

At least one behavioral and at least one electrode measurement
–Behaviorally: VRA (booth, puppets)
CPA

Question 25

Comfort levels/Most comfortable levels

Answer 25

Upper limit of DR Cochlear (Cs): set below max. comfort (right below UCL) due to summation across electrode Medel: highest stim level at which sound is loud, but comfortable AB: most comfortable level-daily listening level. Speech burst are used for setting M-levels (groups of 4 using broadband stim)

Question 26

C/M level measurements

Answer 26

ascending technique -switching from older map: decrease globally by 10 cus and then ascend. -steep loudness growth in some loundness charts are helpful

Question 27

Influences on levels

Answer 27

Speech processing strategy Bipolar vs monopolar stim rate (increase in rate, level decreases) Proximity of electrode array to modiolus (further= more current level, modiolus hugging (lower level)

Question 28

Loudness balancing

Answer 28

Ensure equal loudness on all electrodes - Two methods - -balancing (low to high) - -sweeping (pulse on each channel)

Question 29

Compliance levels

Answer 29

- amount of voltage allowed for each electrode - "out of compliance" = max voltage available from implant is not sufficient to generate the desired current level - going to sound soft. - -cant increase stim units. solution: increase the pulse width.

Question 30

Consequences of being out of compliance

Answer 30

-Insufficent loudness growth, variable loudness, lack and loudness growth distorted sound poor battery life decreased performance

Question 31

Power optimization

Answer 31

- can better type provide enough voltage to deliver the requested amount of current - as required voltage increases, battery life decreases - ->pot. solution: decrease pulse rate - want to use automatic power as much as possible. This is measured when the coil is on the pt.'s head Calculated for each map by determining how much power is needed in the worst case condition to ensure all electrodes are w/in compliance

Question 32

Live voice modifications

Answer 32

``` Tilting Increase/decrease levels on all channels -echoy/boomy= upper limits, bring down C/Ms -low level humming= Ts (bring them down) Gain- too loud, bring down on the processor programming Freq. adjustments -Tinny-HF -Hallow -MF -boomy-LF ```

Question 33

Noise reduction

Answer 33

AGC autosensitivity Adaptive DR Organization (ADRO)- gain adjsutmet at each freq. band BEAM- multi mic -cochlear and AB

Question 34

Patient conrtols

Answer 34

Programs Volume (Cs/Ms) Sensitivity (distance of hearing and perception in noise)

Question 35

Processing strategey

Answer 35

set of rules to convert acoustic input into electrical output ``` sequential or paired Captures following parameters of sound -Time (well) -Intensity -Spectral (poorly) ```

Question 36

Temporal domain

Answer 36

-temporal envelope is important (and is perceived), but so is fine structure.

Question 37

Intensity domanin

Answer 37

- directional mics - mic placement (hear level, head piece, t mic) - automatic gain control (AGC) - input DR **compression** --> takes IDR and puts into electrical DR

Question 38

Spectral domain

Answer 38

NH: 20-20, 000 Hz CI: ~250-8000 (AB and M =60dB at 250) -not much resolution needed for speech as with music. Music of diff, but close freq will be passed through the same filter (perceived as the same sound)

Question 39

Processing strategies

Answer 39

- Continuous interleaved sampling (CIS) -simplest - HiResolution *AB* - Advanced combination encoder (ACE) *Cochlear* - Spectral peak (SPEAK) - Fine structure processing (FSP) *Medel*

Question 40

Continuous interleaved sampling

Answer 40

sequential slowest (1000 stim rate) simpliest - 8 channels bandpass filters AB's version= Multiple pulsatile sampler (MPS) double the stim rate, increases the "temporal" resolution Medel uses CIS+ and HDCIS- wider freq range and use of virtual channels for improved "spectral" resolution.