Adding Multiple Memories

Question 1

What three questions should you answer before creating additional manual programs?

Answer 1

How often are they in challenging environments? (if not often, they don’t need them)
Is it possible to create a program that is noticeably different from the baseline response allowing the patient to hear the difference between programs?
Based on clinical judgment, do you feel your patient can understand (or manage) additional manual programs? (can assess by cognitive questionnaires)

Question 2

What are some factors that make it difficult to achieve a noticeable difference between programs?

Answer 2

Configuration doesn’t require LF gain/output
Feedback limits the ability to add HF gain/output
The receiver size limits output
You can’t increase CR further (especially in the HF)

Question 3

What makes a noticeable different most likely to be achieved?

Answer 3

Threshold loss at 500 Hz is >40 dB
High frequency loss is not too severe (70 dB HL or better)

Question 4

Do individuals with wider dynamic ranges benefit from additional manual programs?

Answer 4

Yes
Have more of an ability to make more changes (more room to work with)

Question 5

Do milder losses with poorer than expected SNR loss require manual programs to control noise in their environment?

Answer 5

Yes

Question 6

How do you conduct a scene analysis?

Answer 6

Identify the frequency range and the intensity of the problematic signal to determine what changes to make

Question 7

What are some possible changes that could be made from a scene analysis?

Answer 7

Raising or lowering TK modifies output for soft input signals
Increasing or decreasing low frequency bands changes perception of volume and sound quality
Increasing or decreasing high frequency bands improves clarity or comfort
Increasing or decreasing intensity of soft input signals improves clarity
Increasing or decreasing intensity of loud input signals improve clarity or increase comfort
Increasing or decreasing MPO manages very loud signals (90+)

Question 8

How would you create a memory to improve intelligibility in a small group?

Answer 8

Need to adjust the LF
Reduce CR below 1.5k Hz to increase linearity (this makes the signal clearer) (lower the soft inputs for LF)
Increase CR above 1.5k Hz to improve comfort (~ 3:1) (lower the loud inputs for HF)

Question 9

How would you create a memory to improve intelligibility in a LF weighted background noise (machinery, crowded places, stable noise)?

Answer 9

Reduce frequency shaping bands below 1.5k Hz to decrease audibility of the low frequency input signals (the lower the freq, the more we are dropping the output)
Increase frequency shaping bands above 1.5k Hz to improve audibility of consonant sounds (the higher the freq, the more you want to increase the output) - high frequency emphasis for clarity
This remedy does not change compression ratio (band change)

Question 10

What can you do if the patient also wants increase comfort? (with speech intelligibility in LF noise)

Answer 10

Raise threshold kneepoint (TK) below 1.5k Hz to 50 dB to attenuate interfering soft LF signals
Increase compression in the LF channel - “one step” by reducing gain for louder input signals (lowers the output of loud LF signals)

Question 11

How would you create a memory to improve intelligibility in a HF weighted background noise? (clattering dishes, vacuum, water running, paper rustling, etc.)

Answer 11

Want to improve tolerance of noise
Increase frequency shaping bands below 1.5k Hz to add richness & audibility to input signals
Decrease frequency shaping bands above 1.5k Hz reduce annoying signals in this frequency range
This remedy does not change compression ratio

Question 12

How would you create a memory to improve intelligibility in a high noise environment? (bar, wedding, etc.)

Answer 12

Raise the threshold kneepoint (TK) above 1.5k Hz to 60 dB because audibility of soft HF input signals does not support intelligibility in this environment
Increase compression ratio above 1.5k Hz “one step” by reducing gain for loud inputs slightly

Question 13

What is the rationale of improving intelligibility in a LF weighted background noise (machinery, crowded places, stable noise)?

Answer 13

Lower LF output decreases upward spread of masking
Increase HF makes consonants louder

Question 14

What is the objective of amplifying music?

Answer 14

Audibility and high fidelity
Want the full musical experience

Question 15

What can limit a patient’s overall satisfaction of music?

Answer 15

A patient’s frequency and temporal resolution issues

Question 16

What are the complexities associated with musical signals?

Answer 16

There is no ‘long-term average” for instrumental music and therefore targets prescriptive fitting formulas are unavailable
Intensity & frequencies variations are significant
Crest factor: Intensity maxima and minima are different than speech (+16 to +18 dB whereas speech is assumed to be +12 dB)
The output waveform of music is “peakier” relative to speech

Question 17

What are the marshall chasin recommendations for musicians?

Answer 17

Select a hearing aid with a microphone that allows a high front-end input range, or…
Remove aids (especially for up to moderate loss)
Lower volume on stereo and increase volume on aid
Place 3 layers of scotch tape over mic to attenuate input by 10-12 dB
Use FM as your input source instead of device microphone

Question 18

How does a hearing aid impact music?

Answer 18

Squishing signal into a smaller range, doesn’t give the peaks and valleys that are important for music (compression; non-linear signals)
Getting the TK as low as possible will help them hear the really soft sounds
MPO TK needs to go up, to expand the dynamic range
Processing delay possible – direct signal will arrive before the amplified signal
One signal is arriving faster than the other with a vent
DNR will attenuate as steady state sound and attenuate it (sustained note)
DFS will potentially create an out-of-phase signal to cancel the sustained note

Question 19

What changes should you make to a dedicated music program/memory?

Answer 19

Disable digital feedback suppression (DFS), digital noise reduction (DNR), adaptive directional microphones, and frequency lowering
Reduce compression ratio in LF by raising gain for loud input signals
Raise MPO (improves brightness, crispness of music; allows room for higher crest factor)