Final Exam Flashcards
Challenges and fitting strategies when A/B gaps are present
- Additional gain is needed to overcome the attenuation caused by the mechanical loss
- ABG attenuate the signal amplitude before it arrives to the cochlea
ABGs with normal BC thresholds
compression is not needed because the dynamic range is normal
* Use of 1:1 linear signal processing (or very low CR) is fine
ABGs with abnormal BC thresholds (mixed loss)
Compression is needed in addition extra gain due to the reduced dynamic range
Explain why it is beneficial to measure the RECD on every adult’s ear canal
- Accurately converts an individuals HL audiometric thresholds to SPL (more personalized)
- Using RECD conversion values calculates ear canal SPL within 1 dB creating customized conversion values to create accurate fitting targets
what accurately converts an individuals HL audiometric thresholds to SPL (more personalized)
RECD
Using RECD conversion values calculates what?
Using RECD conversion values calculates ear canal SPL within 1 dB creating customized conversion values to create accurate fitting targets
Define RECD procedures based on ANSI Standards
- RECD measurement can be made with a custom earmold or EAR insert
- The same coupler for BOTH measurements
- The ANSI standard requires use of the HA-1 coupler
What do the RECD ANSI standards mean by the same coupler for both measurements?
This means you use a foam tip to measure the ear canal resonance AND the HA-1 coupler resonance
OR…
Use a custom earmold to measure the ear canal resonance AND the HA-1 coupler resonance
The ANSI standard requires use of what coupler?
The ANSI standard requires use of the HA-1 coupler
Be prepared to interpret RECD data
Describe the expected impact of slit leaks on RECD values
A negative LF value suggests a slit leak is present
- For correction, check the seal of the foam tip
A good RECD the “difference” should be
RECD: the “difference” should be a positive value
Describe the expected impact of blockage on RECD values
A negative RECD >10 dB in the 4– 6 kHz region suggests your probe tube is blocked
A negative RECD _____ dB in the _____ kHz region suggests your probe tube is blocked
A negative RECD >10 dB in the 4– 6 kHz region suggests your probe tube is blocked
How does the presence of perforation or PE tube impact the measured RECD
Negative LF results are expected when perfs or PE tubes are present
- Below 1.5 kHz, RECD will be up to 8 dB lower than the adult average
* This indicated the ear canal volume is larger than normal
If the RECD is above the dotted line/average this means what?
Samller canal than average
If the RECD is below the dotted line/average this means what?
Larger canal than average
A negative LF value suggests a
A negative LF value suggests a slit leak is present
A negative RECD >10 dB in the 4– 6 kHz region suggests
A negative RECD >10 dB in the 4– 6 kHz region suggests your probe tube is blocked
Below 1.5 kHz, RECD will be up to 8 dB lower than the adult average suggesting
PE tube or Perf
This indicated the ear canal volume is larger than normal
Below ____ Hz, RECD will be up to ____ dB lower than the adult average for PE tubes or perfs
Below 1.5 kHz, RECD will be up to 8 dB lower than the adult average
What is wrong?
Slit leak
A negative LF value suggests a slit leak is present
What is wrong?
Blocked probe tube
>10db in 4-6khz region
Whats wrong?
PE tube or Perf
below 1.5khz RECD will be up to 8db lower than the average
Whats wrong with TOP?
top: Mastoidectomy
open mastoid cavity decreases function in mid to high freq
Whats wrong with bottom
Bottom: Middle ear effusion
MEE increase RECD in mid to high frequencies - increased stifness of TM
Frequency lowering verification and modification
Verify Audibility of High Frequency /s/
- Goal is to add the least amount of FL required to put the upper shoulder of the /s/ response into the MAOF (maximum audible Output frequency range)
- Its recommended you leave FL disabled for the first few weeks for adults
what is the goal of frequency lowering?
Goal is to add the least amount of FL required to put the upper shoulder of the /s/ response into the MAOF (maximum audible Output frequency range)
what is aided functional gain?
The difference between the aided threshold and the unaided thresholds provided by the HA = functional gain
- aided threshold - unaided threshold = function gain
- measured using pure tone signals in the soundfield
how is aided functional gain measured?
measured using pure tone signals in the soundfield
reasons for using aided functional gain?
- REM equipment is not available
- Gooey cerumen clogs probe mic
- Pediatric fittings or uncooperative patients
- CI, BAHA, Lyric fittings
- Some federal government agencies require the test
these are things would list if Real ear wasnt practical
What’s the ideal aided threshold for aided functional gain?
- The ideal aided threshold should at least allow the lowest intensity level of normal speech to be audible
- Expected aided functional gain is often not achieved, especially in high frequencies
aided functional gain pitfalls
- Test-retest reliability is poor.
- Testing only identifies the threshold of audibility
- Limited number of frequencies assessed
- Ensuring WDRC successfully shaped the signal into a reduced dynamic range requires multi-intensity assessments
- Aided thresholds are invalid for near-normal hearing
- Hearing aid features could suppress audibility of tones:
- Loss of high frequency aided functional gain in nonlinear hearing aids is caused by AGC kneepoint
Efficiency of aided functional gain
every time you modify gain you need to perform aided functional gain measures
List alternative “conformity” (verification) protocols
- On- Ear Real Ear Verification
- RECD measurement and test box programming
- Aided Speech intelligibility Measures
- Aided verification of adaptive speech in noise performance
- Aided loudness ratings
- Subjective SF ratings
what conformity verification
* demonstrate improved intelligibiity
* demonstrate the benefits of technology designed to improve understanding in noise
* demonstrate continued limitations of hearing in noise and the benefits of speech reading
Aided Speech intelligibility Measures
Aided Speech intelligibility Measures
- demonstrate improved intelligibiity
- demonstrate the benefits of technology designed to improve understanding in noise
- demonstrate continued limitations of hearing in noise and the benefits of speech reading
what conformity verification
* Ensures SNR loss did not degrade with amp
* Functional verification of improved performance with directional or remote microphones
* use SNR loss results to counsel on aided hearing aid benefit
Aided verification of adaptive speech in noise performance
what conformity verification
* Patient is aided bilaterally and judges how loud the sounds are based on chart while listening to a passage
* 45 dB SPL = they should rate it a 1,2,3
* 65 dB = rate it 3,4
* 85 = be below 7
Aided loudness ratings
Aided verification of adaptive speech in noise performance
- Ensures SNR loss did not degrade with amp
- Functional verification of improved performance with directional or remote microphones
- use SNR loss results to counsel on aided hearing aid benefit
Aided loudness ratings
- Patient is aided bilaterally and judges how loud the sounds are based on chart while listening to a passage
- 45 dB SPL = they should rate it a 1,2,3
- 65 dB = rate it 3,4
- 85 = be below 7
- speech intelligibility judgements
* Patient judges ‘ease of listening’ while listening to passages presented at 50 dB HL - speech quality judgments
* Patient judges sound quality while listening to passages presented at 50 dB HL
Subjective Sound Field ratings
Subjective Sound Field ratings
- subjective speech intelligibility judgements
* Patient judges ‘ease of listening’ while listening to passages presented at 50 dB HL - Subjective speech quality judgments
* Patient judges sound quality while listening to passages presented at 50 dB HL
ANL similar
Describe the 3 considerations made to determine if manual memories are warranted
- How often are they in challenging environments?
- program that is noticeably different from the baseline
- patient can understand (or manage) additional manual programs?
manual program modifications to improve
Speech in a low-freqency weighted background noise
- Change the frequency response without changing compression ratio
- Reduce frequency shaping bands below 1.5k Hz to decrease audibility of the low frequency input signals
- ncrease frequency shaping bands above 1.5k Hz to improve audibility of consonant sounds
- Change the frequency response without changing compression ratio
- Reduce frequency shaping bands below 1.5k Hz to decrease audibility of the low frequency input signals
- ncrease frequency shaping bands above 1.5k Hz to improve audibility of consonant sounds
Speech in a low-frequency weighted background noise
- Raise LF threshold kneepoint (TK) below 1.5k Hz to 50 dB to attenuate interfering soft LF signals
- Increase CR in the LF loud input channel- “one step” (1-2 dB) this lowers the output of loud LF signals
Comfort listening in a low frequency (LF) weighted background noise
think 50 comfortable listening level