Fitting Formulas
Name two compression fitting formulas
NAL-NL2
NAL-NL1
DSLv5.0
NAL-NL3
LGOB
IHAFF
FIG6
SCALADAPT
A 1:1 compression ratio suggests what type of fitting?
A linear fit.
What is the primary role of noise reduction?
Improve listening comfort/ease
Name two things you should immediately look at when you connect a hearing aid to software?
•Datalogging
•Gain curves
•Feedback manager
•Compression ratios
VC and program change
What is the half-gain rule?
Gain at each frequency should be equal to exactly half of the amount of hearing loss at that frequency.
What is the compression threshold?
The input level at which compression starts
How much improvement (in dB) is expected when utilizing directional microphones?
1-4 dB
What is an appropriate action to take when a new hearing aid user reports everything is too loud?
- Counsel regarding realistic expectations
- Implement acclimatization
___________ hearing aids utilize a rubber tube which connects the aid to the earmolds
BTEs
An area of the cochlea without IHCs
The inverse of compression is _____
The sensitivity pattern of a microphone is known as a ___________
Polar plot
What are two questions to consider when a patient reports that "speech is not clear" while utilizing their hearing aids?
•Are the hearing aids working well?
•Is frequency lowering activated?
•How are the compression ratios?
•What coupling is the patient using?
•Is feedback manager cutting gain?
•Is output audible? (REM)
The most widely used electronic program that houses all manufacturer software, stores patient information, and allows for connectivity of the hearing aids is called _____________
NOAH
List two difficulties of creating a fitting formula
•Optimal gain is likely input dependent
•Optimal gain can be dependent on loudness perception and frequency resolution which is not easily measured
•Acclimatization
•Preferences vary dependent on if they prefer intelligibility or comfort which may vary dependent on what type of input it is
•Dead regions
•Varying configurations of hearing loss
List two goals of compression
•Decrease dynamic range
•Avoid discomfort, distortion, and damage
•Reduce inter-syllabic and inter-phonemic differences (next slide)
•Increase sound comfort
•Reducing differences in long-term level
•Normalizing loudness
•Maximizing intelligibility
•Reducing noise
List two reasons to utilize frequency lowering?
•Dead regions
•Areas that cannot be amplified
•Feedback potential
If feedback manager is turned on/ has been completed, and a patient reports concerns of feedback, what are some two things you might consider asking the patient or changing?
•When does the feedback occur?
•What is normal and what is not?
•Is there gain for unaidable frequencies?
•What type of coupling does the patient use?
What is the second largest zinc-air battery size?
Size 13
Name one difference between NAL and DSL
NAL: maximize speech intelligibility, equalizing loudness, takes into account gender and experience
DSL: maximize speech audibility, loudness normalization, pediatrics, more low and high frequency gain, takes into account listening in noise and LDLs
In what type of scenario would short attack/release times be ideal?
Impulse noise reduction
Name three types of feedback suppression
•Gain-frequency response control/Notch filtering
•Phase control
•Feedback path cancellation
•Frequency shifting
Per Windle et al. 2023, what are two recommendations for hearing aid fitting and/or programming for a patient with slower processing?
•Compression ratios < 2:1
•Avoid frequency lowering
•Use slow-acting compression (longer attack/release times)
•Use closed fittings/molds to improve directionality
The method of which a RIC receiver is "connected" to the ear canal is known as ___________
Coupling