Final Exam - Readings Flashcards
(80 cards)
What are ways in which educating the patient is important?
- provide realistic patient choices
- encourage self-efficacy
- convey sense of unique issues and abilities (one size does not fit all
Prescription procedure
- practical way to select a hearing aid & adjust amplification characteristics for each hearing impaired person
amplification target (prescription target)
required amplification characteristics that can help assume relationship between measured patient characteristics and required amplification characteristics
evaluative approach
- contrast to prescriptive approach
- number of hearing aids or response shapes randomly chosen, each is tested on patient to find the best one
- totally impractical because of the large number of characteristics
Mirroring of the audiogram
the gain needed at each frequency that is equal to the threshold loss at that frequency minus a constant
half-gain rule
- because the original MCL formula didn’t take into account the variation of speech energy across frequency lybarger made a different approach
- averaged across frequencies the amount of gain chosen with approximately half of the threshold loss
- underlies several prescriptive procedures
What are two different auditory things used for the basis of prescription?
MCL
Measuring hearing thresholds
Name reasons why it is hard to determine a relationship between hearing loss and gain.
- depends on type of input signal
- depends on loudness perception and frequency resolution ability
- may depend on nature of the auditory input that a person may be accustomed to
- may not be a single optimum gain frequency curve (because a person may want to have better intelligibility, comfort etc)
REAG
real-ear aided gain
- specifies how much SPL at the eardrum should exceed the SPL in the incoming field
REIG
- real-ear insertion gain
- describes how much more signal should be at the ear drum when the person is aided compared to unaided
REUG
real-ear unaided gain
REAR
real-ear aided response
What are some types of prescriptions for linear amplification?
- POGO
- NAL
- DSL
POGO
- Prescription of gain and output procedure
- straightforward application of the half-gain rule with an additional low cut (low frequency ambient noise)
- insertion gain at each frequency is equal to half the hearing loss at that frequency, plus a constant
- only intended to be used only for hearing losses up to 80 db HL
POGO II
- greater losses, gain increases by 1 dB for every 1 dB increase in hearing loss
- people with severe and profound hearing losses prefer to listen to speech at low sensation level
NAL
- national acoustic laboratories of australia
- maximize speech intelligibility at preferred listening level
- type of gain prescribed by NAL is insertion gain
Why was the NAL formula changed?
- it did not achieve equal loudness, especially for those with a steeply sloping loss
- revised formula became known as NAL-R
NAL-RP
- based on measured speech intelligibility, and subjective preferences for quality and intelligibility in quite and in noise for mild to profound loss
DSL (linear)
- desired sensation level
- wanted to provide audible and comfortable signal in each frequency region
How does DSL differ from POGO and NAL-RP?
- target is in real-ear aided gain instead of real-ear insertion gain
- DSL is convenient for infants and young children
- DSL procedure doesn’t attempt to make speech equally loud but instead comfortably loud
Why is the correct prescription important?
- If you don’t have the ability to change the volume control on your own you can’t compensate for errors made in programing
- they can’t change the frequency response shape, this needs to be done correctly in the programming
What is important to consider when trying to pick between the different prescription methods?
- type and configuration of loss
- hearing aid ability
- age (DSL good for kids and cognitively/dexterity challenged adults)
- technology
Name some difficult issues with prescription.
- dead regions
- prescribing compression thresholds
- need for accuracy and prescription
- preferred loudness
- acclimatization
- adaptation to gain and frequency response
acclimatization
gradual longterm changes in the hearing abilities of patients