AC HA Styles & Fitting Apps (2B) Flashcards
Explain the five benefits associated with use of bilateral amplification.
1 Allows audibility of ILD, ITD & HRTF signals
2 Binaural loudness summation
3 Improved localization
4 Binaural squelch (binaural release of masking)
5 Minimizes risk of “unaided ear effect”
6 Suppresses bilateral tinnitus
how each binaural benefit supports improved speech intelligibility in quiet or in noise.
Describe a head shadow’s impact on different frequency ranges. How does head shadow impact signal-to-noise ratio in each ear?
what are the threshold & suprathreshold benefits of binaural loudness summation
@ threshold +3dB
@supra +6-8dB
@ 50dB HL +6dB
@ 90dB HL +9dB
what is binaural loudness summation
when ap in bs increase loudness when 2 ears receive auditory input signals
how does binaural loudness summation support HAF strategies
PT perceives greater loudness w/ bilateral devices
less gain is needed to reach comfortable listening levels
what is binaural squelch
it is the abilty of the as to combine information from both ears centrally and segregate the speech from the noise by the ITD & ILD differences between both ears
what is the benefit of binaural squelch
helps improve intelligibility in noise and focus on 1 signal while ignoring others
offers a SNR improvement of 2-3dB
Describe the research findings related to the “unaided ear effect
~25-33% of individuals with symmetric loss suffered from reduced word recognition scores following 1 year of monaural hearing aid use.
Puretone thresholds did not change but speech intelligibility declined on the unaided ear!
*ONLY HAPPENS WHEN YOU NEED TWO AND ONLY PROCEED WITH ONE
what caused the unaided ear effect over the year?
neural connections of aided ear were stimulated and strengthened and lack of audibility in unaided ear made the system less efficient and increased discrimination problems
explain each binaural process in a simple way that supports a patient’s understanding of the benefit
amp is less loud and more balance
more natural and better tolerated
easier to hear higher pitches
easier to hear speech in noisy environment
easier to better hear speech in the presence of noise
Having both ears makes it easier to locate where sound is coming from
If you take a walk you will be able to know where a car is coming from and if it is far away or nearby or even when it is behind you
Sound amplification is more comfortable and pleasant
With only 1 HA, the amplification must be louder to compensate for your ear without a hearing aid
Sounds sound less natural and are more distorted especially for loud sounds which can be unpleasant
HA are made to work in pairs like speakers making it possible to hear smaller and higher pitched sounds better like women and children’s voices
Better understanding of speech in noisy environments
Whether at a restaurant or family parties hearing with both ears allows your brain to better separate important speech sounds from information of lesser importance
Sound quality is superior
It is more pleasant to appreciate music with both ears
Wearing two HAs prevents sensory deprivation
If one of your ears suffers from a more important loss and is not fitted with a hearing aid, that ears ability to understand speech decreases more than if it was fitted over time
This is why it is important to check your hearing on a regular basis to decrease the impact hl can have on your daily life
counseling points if a PT only wants 1 HA
Explain evidenced based research related to unaided ear effect
It’s possible they’ll have more difficulty adjusting to a bilateral fitting in future
advanced digital signal processing features require two devices “talk” to one another for function optimally
Offer a trial period to try two devices
what is binaural interference, what causes it,
poorer speech recognition with both ears than with the better ear alone,
Progressive age-related atrophy of the corpus callosum reduces speech intelligibility with binaural input
what is the prevalence and population effected by binaural interference
5-10% of older PTs with bilateral amp
Fitting ranges are impacted by
Proximity of microphone to receiver
smaller devices produce less output
Size of receiver
larger receivers produce greater output
Physical properties of sound bore (length, diameter)
Vent size
Microphone location
Proximity to tympanic membrane
Near normal low frequency hearing typically doesn’t require an amplified signal. whyy
because the intensity of a “direct signal” is audible without amplification
