Download MEASURING IN-SITU REAL EAR AIDED RESPONSE (UNITY)

MEASURING IN-SITU REAL EAR AIDED RESPONSE (UNITY).
WARNING: When using the probe microphone equipment be VERY careful with
the microphones as they are easily damaged. Also please do not change
headsets between the different systems as each system has been calibrated for
the particular headset.
AIM:
Familiarisation with real ear probe tube microphone
measurements
OBJECTIVES:
Competency in measuring:
 REAR (REUR, REOR, REIR)
1. Click on NOAH, when it asks for a password select OK.
2. Click on FILE, select NEW CLIENT, enter any Last Name, First Name &
DoB (if typing in manually our computers use American format)
3. Click on OK, then Select ALL CLIENTS and double click on your entered
client.
4. Click on AUDIOMETRY MODULE
5. Enter the following hearing loss:
500 Hz
1000 Hz
2000 Hz
4000 Hz
Right Ear 35
35
40
40
Left Ear
35
40
40
35
(You can copy one ear’s threshold onto the other ear by clicking on EDIT, then
select COPY TO OPPOSITE EAR.)
6. Click on AUDIOGRAM, select SAVE (or click on disk icon) and then click
on lower small ‘X’ to close the window.
Save disk icon
Click on lower
‘x’ to close window
7. Attach Starkey Strata A312 hearing aid to the programming leads and
plug into the hi-pro box.
8. Click on OPEN MODULE SELECTION icon.
9. Click on your STARKEY ICON, then HEARING AID FITTING to launch
the hearing aid software.
10. The software may appear behind your ‘Legacy Host’ screen, if it does
minimise the legacy host screen so you can see the Starkey software
Starkey software
Legacy Host Screen
(minimise & it will drop to the
bottom of your screen & the Starkey
software will become accessible)
11. Click on the appropriate ear (Right or Left) then click on READ.
12. If the hearing aid has been programmed before it will ask you if you want to
use the audiogram from the hearing aid or the current session. Which one do
you think you should use? ______________________________
13. Click on CURRENT SESSION. If the ‘Reading Device’ screen doesn’t
disappear then click on the RED CROSS.
14. Change the prescriptive procedure to DSLi/o and mute the hearing aid.
15. Click PROGRAM
16. Find the NOAH platform again. It may be minimised, and on the tool bar
at the bottom of your screen, if so click on it.
17. Open the OPEN MODULE SELECTION icon again (click on it).
18. Click on ‘MEASUREMENT’ so that you have access to all the
measurement modules. Double click on UNITY PC PROBE to launch the
REM module.
19. In TARGET GAIN box select PROBE and DSL i/o prescription rule
20. Select BTE as the HI Type (this may already be selected) but ignore the
other boxes.
21. Click on the SCREWDRIVER ICON and set up the following
Screwdriver
icon
Fixed CR for non-linear
hearing aid. Phillips
only aid
with curvilinear (variable
CR)
Using predicted
ULLs to
set MPO targets.
Check
DoB
Insert earphone
with
foam tip was used
for
PTA
Select low
CT
for WDRC
aids.
Using predicted
RECDs
to convert PTA in dB
HL
to PTA in dB SPL.
Using child LTASS
rather
than adult LTASS.
Using predicted RECDs to
convert
real ear Hearing aid
response to
coupler response.
Click on OK
when finished
completed.
22. Click on MEASUREMENT RIGHT/LEFT
Measurement L & R
23. Prepare to calibrate the probe tube:

Use a new black tip probe tube, attach it to the probe microphone
attachment then position the end of the probe tube so that it is aligned with
the reference microphone.

Hold the probe tube and reference microphone facing the loudspeaker at
the same distance you will be placing the individual (0.5-1m as
recommended by the manufacturer).
24. Select Task from the menu bar and choose Probe Calibration.
Click
CALIBRATION.
If happy with the calibration response, click OK. As an extra cross check,
change the signal type to pink noise and click on start. Check to see that
you have a flat line. Click stop to cancel the measurement. If you don’t get a
flat line repeat your calibration.
25. Select Aided response. Identify what you’re looking at. If a coupler icon
appears in the top right corner of the display screen double click on it to change it
to a face icon as you will be making IN-SITU measurements.
Aided response
25. Position the subject in the appropriate position (50-100 cm) in front of the
loudspeaker. Examine ear using otoscope and check for discharge or
excessive wax.
26. Carefully position the probe tube (approx 27mm past tragal notch and at
least 5mm past the earmould) Check its position with an otoscope.
27. Carefully insert earmould with hearing aid attached and switched on. Take
care not to move probe tube.
28. Set input level to 65 dB then select Speech noise. Click record. Check
to see if the hearing aid matches targets, if it doesn’t adjust the
electroacoustic parameters of the hearing aid appropriately.
29. Once targets are met at 65dB change the input to 80 dB (warn subject it
may be loud) and click on record. Ideally you would do the same for 50
dB input using same stimulus but the training room will be too noisy to
make this measurement so you don’t need to do it. Once you are happy
with the response of the hearing aid you can save and exit.
MEASURING REUR, REOR & REIR
In your own time you might like to practice measuring more traditional real ear
measurements such as the real ear unaided response (REUR), real ear occluded
response (REOR) & real ear insertion response (REIR). These measurements
are only appropriate for children whose ear canals are the same size as adults
(have the same resonant peak).
1.
Delete all previous curves. To measure Real Ear Insertion Response
(Gain) click on TONE AUDIOGRAM again and select NAL-NL1.
2.
Click on the screwdriver icon; check DOB, change orientation – 0
degrees: compression channels 2. Return to right/left measurement
3.
Remove the hearing aid ensuring the probe tube remains in place. Check
that the input level is set to 65 dB then click on open ear icon. This is your
unaided response (insitu gain of the open ear)
QUESTION:
At what frequencies are there peaks in the REUR?
________________________________________________________________
____________________________________________________________
Do these peaks correspond with an average adult REUR?
______________________________________________________________
4.
If the REUR does deviate from average, re-insert the probe tube checking
it has not been blocked with wax or positioned against the ear canal wall.
Also check for middle ear anomalies.
5.
Carefully place the earmould and hearing aid in the ear taking extra care
to not move the probe tube. Use Vaseline if necessary.
6.
Switch off the hearing aid and click on Occluded response icon. Note
how the insertion of the mould removes the ear’s natural resonance.
QUESTION:
Does the REOR curve exceed the REUR at any frequency?
__________________________________________________________
If yes, why do you think it does and what could you do to modify the REOR
response?
________________________________________________________________
________________________________________________________________
__________________________________________________________
7
Turn on the hearing aid, click insertion gain icon and obtain a REIR (at 65
dB) using speech noise. What the software is actually doing is measuring
the aided response (insitu aided gain), subtracting it from the unaided
response and displaying the resultant real ear insertion response. Does
the REIR of the hearing aid meet targets?
If not, manipulate the electroacoustic parameters on the hearing aid to best meet
targets.