Verification and Validation Flashcards
what info do we need to fir a HA?
-hearing test results
- thresholds
- ear specific
- min o f4 thresholds, the more the better
- we want BC
-check if masking is done properly
- reliable and repeatable responses
- if you only had 2/4 thresholds or didn’t have ear specific info, whether you fit the aid now or confirming this info with an extra appointment, its up to you and child specific, ask other people in your department BUT make sure its all safe
whats involved in the selection of HA’s and featured?
-type of HA and ear mould- so they wear it if they are more comfortable and it needs to be soft so they don’t hit their head and hurt it
-retention device (huggies) - help it not fall out
- tamper proof battery doors for safety
- volume control- is the child old enough to manipulate this?
- FM compatibility for school
-omni directional mic until 2 years old so they can pick up sound from all around
- data logging and lights on HA- help parents know when they need to chnage the battery- - paediatric hooks- stop falling off
- tube locks- the child would otherwise just pull it out
what does verification do?
ensures the hearing aid output is optimal
- for paeds most commonly use RECDs
- the child’s thresholds are converted to targets and an aid is programmed to a prescriptive formula (e.g. DSL) and measurements are now taken of their ear (real ear measurements) in order to ascertain the targets are being matched by the hearing aid.
- This is done ear by REAR (Real Ear Aided Response) or RECD (Real Ear Coupler Difference) measurements.
- It is often done in a test box and does not tell us the real world performance of the aid.
what is RECD ?
the difference between the SPL measured in the real ear and the SPL measured in a 2cc coupler
- RECD is used to convert HA performance in the 2cc coupler into the real HA performance
what impact does the size of the ear canal have on the RECD?
the smaller the ear canal, the greater the SPL measured at the ear drum (& the greater the RECD)
whats the advantage of RECD’s?
- one fairly quick measure
- all further programming of the HA can be done in the 2cc coupler allowing the child to leave the room if needed (it takes about 30 seconds)
how often is RECD performed?
- at least every 3 months up to 2 years of age and 6 monthly following this until in situ REMS are completed
- they should be repeated if the child has a new earmould
how is PTA recorded for RECD and why?
PTA needs to be recorded with inserts, not headphones, for correct conversion to dB SPL
- you can do headphones but you need to do the correction factor for conversion from dBHL to dBSPL, the earmold should be able to pass the issue of wax with inserts
how is RECD recorded if the child has a temporary OME?
- use a previously measured RECD or predicted average RECD to set up aids (depending on how long ago RECD was measured)
what do you do if you don’t have enough time for bilateral RECDs?
-if time, measure RECD for both ears, however, it is adequate to measure the RECD for one ear and use bilaterally, (measure on ear with best fitting mould/ least wax/ most normal tymps)
- you can do both at the same time
what if you see the RECD trace and the freq are too low/ negative?
negative values=
- is mould loose?
-missed perforation
- incorrect tubing?
bigger negative values= perforation
even more negative= potential blockage or tube crimping
what if you see the RECD trace and the freq is too positive/ too high
glue?//
- CHECK for middle ear effusion
RECD Process:
1- Do your REM calibration like you would do normally.- for accuracy during testing
2- You have an additional tube not he REM tube, which you would place in the coupler. You then record the coupler response.- gives baseline
3- Attach the insert into the patients ear mould and put the REM tube and the ear mould in the patients ear. You then do a real ear recording.
4- The software will workout the difference and you will get RECD.- this difference shows the patients unique ear canal acoustics
in a case study what are your steps?
- read it
- check audiogram
- is there anything missing? (if masking is missing, the child is 3y, unlikely to get masking) but make not of whats not be done (masking unattempted’)
- type of loss?
- transducer?
- type of mould
- aid?
0presecription manager? - necessary to run feedback manager?- t cuts out access gain so as the mould becomes looser it can help reduce feedback.
- if RECD is done in 1 ear, why? was it noted?
would you always need to programme feedback manager?
not if the HL doesn’t warrant it, so if the HA isn’t giving THAT much gain, you don’t need it
whats the standard follow up after fitting?
4-6 weeks
what follow up and instructions should be given after fitting appt?
-how do use the HA?
- insertion of the mould?
- discussion around HL and usage
- contact details fro the ToD
- Audiology Dept contact details
- follow up appt schedule
1- accurate assessment
2- verification: ensure the HA output i optimal
3- hearing aid features
- 3- info and instructions
whats validation?
ensures the wearer is obtaining benefit from the HA
- is a subjective (or can be objective) ‘real world’ evaluation of the performance of the HA.
- This is very important as even if we have achieved good targets on verification, we need to know if the aid is actually providing optimal speech recognition and/or a listening experience that is helpful and pleasant / comfortable for the child.
is validation objective or subjective?
subjective
why is validation important for paeds?
- even if we have achieved good targets on verification, we need to know if the HA is actually providing optimal speech recognition and/ or a listening experience that is helpful and pleasant for the child
- young children fitted with HA’s are not able to give direct feedback on the performance of the HA
- you cant leave child receiving improper amounts of under or over amplification
