Fitting Formulas Flashcards
What falls under prescribing fitting formulas?
- Gain/Output Based
- CT or CR
- MPO
What are the starting points you should consider to find the best fit for your pt?
- Speech Intelligibility
- Sound quality
- Listening comfort
What does Non-Linear fitting formulas consist of?
- Compression
- Multiple Inputs
- Multiple Channels
What is loudness normalization?
Across all frequencies, overall loudness of sounds being normalized. Sounds that are soft or loud would be amplified for a HL person
What is loudness equalization
All frequency bands of speech are amplified to contribute equally to loudness of speech.
What is the goal of DSL v5.0?
Provide maximum audibility while maintaining comfortable loudness across all inputs
List characteristics for DSL v5.0
- Specific to WDRC devices
- Suitable for children
- Threshold based
- Age based
- Convenient
List Age & Etiology characteristics for DSL v5.0
- Adult/Acquired v Pediatric/Congenital
- Children prefer greater gain because they’re learning language
- 7dB for moderate
- 3 dB for severe
List type of HL characteristics for DSL v5.0
- CHL or MHL, give increased gain
- Will be more linear
- Raises predicted limit of comfort by 25% of average ABG
- Dependent on size of ABG
- Maximal CHL –> 9dB for mild losses, up to 5dB for severe losses
What is the goal of NAL-NL2?
Maximize predicted speech intelligibility while making overall loudness sound normal
NAL-NL2 has
- Higher CR
2. Optimize gain at low levels to avoid slightly higher CR
What is the goal with verification?
Maximize speech understanding
What is the goal of loudness normalization?
Relative loudness of different frequency components of complex sounds will be preserved
What is the problem with Loudness Normalization?
Not all speech frequencies carry the same importance
What is the goal of loudness equalization?
- It increases the potential for understanding that once HA is set to user level.
- Audibility would be maximized if all freq bands of speech contributed equally to loudness perception.
For NAL-NL2, what is gender preference for gain?
Male: Prefer more
Female: Prefer less volume ~2dB
For NAL-NL2, what is gain preference for user preference?
New User: Slighty less
Experienced: Slightly more
For NAL-NL2 & DSL v5.0, when would you prescribe less gain?
For binaural fittings, since they’re wearing 2 HAs
For NAL-NL2 what is gain preference for pediatrics?
- Provide greater amount of gain to them than adults
- 5dB @ mid inputs
- More @ low “ “
- Less @ high
On the Verifit, does the following impact REAR targest? Gender Experience CT Compression Channels Compression Speed EM tubing type Vent size
No
a. Non-Linear fitting formulas consist of?
b. List the fitting formula under each that’s important for us.
a. Normalization & Equalization
b. Normalization: DSL v5.0
Equalization: NAL-NL2
What does non-linear fitting formulas focus on?
- Acclimatization
- Preferred Loudness/Gain
- Degree of HL
- CT
What is the goal of non-linear fitting formulas?
Fit the world of sound into the DR of the individual with hearing impairment
What is the goal of linear fitting formulas?
Make speech presented at avg audible level, while keeping loud speech & other noises from becoming uncomfortable.