MEASURING IN-SITU REAL EAR AIDED RESPONSE (AURICAL)
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:
Þ 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 HzRight Ear / 35 / 35 / 40 / 40
Left Ear / 35 / 35 / 40 / 40
(You can copy one ear’s threshold onto the other ear by clicking on EDIT, then select COPY TO OTHER EAR.)
6. Click on AUDIOGRAM, select SAVE (or click on disk icon) and then click on lower small ‘X’ to close the window.
7. Attach Starkey Strata 312 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 (see diagram over page)
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 close the message box (click on it’s X).
14. Change the prescriptive procedure to DSLi/o and mute the hearing aid.
15. Find the NOAH platform again. It may be minimised to the bottom of your screen, if so click on it.
16. You want to have access to the OPEN MODULE SELECTION icon again (click on it).
17. Click on ‘MEASUREMENT’ so that you have access to all the measurement modules. Double click on AURICAL REAL EAR M to launch the REM module.
(See additional Aurical notes to learn how to customise shortcut keys back in your own clinics).
18. The ‘DSL set-up targets’ screen defaults on our computers (click on target if it doesn’t, then OK). This is an extremely important screen as DSL uses the information you input to calculate frequency gain targets. Click on the same selections as below (selections in YOUR clinic will vary depending on your set up etc):
Click when all options have been selected.
19. Ensure you are in INSITU SPL mode. If you are NOT click on MODE and make sure ‘Coupler Test’ is NOT selected.
20. You are now going to calibrate the probe tube (must be done every time you change the probe tube). Use a new black tip probe tube, attach it to the probe mic attachment then position the end of the probe tube so that it is aligned with the reference microphone (see manual for picture). Hold the probe tube and reference microphone facing the loudspeaker at the same distance you will be placing the individual (90cm as recommended by the manufacturer).
21. Click on TUBE CAL. It should look similar to the screen below. If calibration is acceptable click OK, if not re-calibrate.
22. As an extra cross check, keep holding the probe tube in the same position as before, click on PURE TONE SWEEP then click on REOR. Check to see you have a flat line.
23. Click on MODE and check that FFT has been selected.
24. Click on VIEW then ENABLE ON TOP MODE. This re-sizes your screen so that you can see both the hearing aid manufacturer and REM screen at the same time. Note when you do this, the GREEN TICK to the top right of the screen shades out. You will have to de-select ENABLE ON TOP mode to get the GREEN TICK back if you want to save your data. GREEN TICK indicates SAVE & EXIT.
(There is a fault in the software because if you go FILE you will see that Save & Exit is ticked and you presume your data would automatically be saved…… it WON’T BE UNLESS YOU CLICK ON THE GREEN TICK.)
25. You want to be able to see both the REM module and Starkey hearing aid software at the same time. See below.
26. Position subject in the appropriate position (90 cm) in front of the loudspeaker. Examine ear using otoscope and check for discharge or excessive wax.
27. Carefully position the probe tube (approx 27mm past tragal notch & at least 5 mm past the earmould). Check the positioning with the otoscope.
28. Carefully insert the earmould with hearing aid attached and switched on (make sure you un-mute the aid in the software). Take care to not move the probe tube.
29. In the Aurical REM module, check that the input level is set to 65 dB then select REIR 1 (stands for Real Ear In-situ Response not to be confused with Real Ear Insertion Response). Check to see if the hearing aid matches targets, if it does not, adjust the electroacoustic parameters of the hearing aid appropriately. Don’t forget if you are exceeding targets in one frequency region you can use the FILTER DESIGN to attenuate specific frequencies.
30. Once targets at 65 dB are met, change the input to 80 dB (only do this if it is OK with your subject as it maybe loud) and click on REIR 2. Adjust the ‘output parameters’ to change the response at 80 dB. In clinic you would also check 50 dB input but the training room will be too noisy to check this. In clinic you would also run a 90 dB pure tone sweep to check the maximum output of the hearing aid. You may choose to do this ‘in-situ’ or you may check this in the coupler (Change mode to Coupler Set-up). Once you are happy with the response of the hearing aid ensure you PROGRAM the changes into the hearing aid. In clinic you should aim to get responses similar to those on the next page.
31. To SAVE the REM response curves click on VIEW and de-select ‘Enable on top mode’. Once you do this the screen will re-store to it’s normal size and the GREEN TICK on the top right of the page will re-appear. Click on this and you will save and exit the measurement module.
32. Return to the Starkey software and click on NOAH drop down menu and
click on 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. To measure Real Ear Insertion Response (Gain) click on TARGET again and select NAL-NL1, click on OK and the setup menu will appear. If this is the first time you have used NAL-NL1 you may need to enter a password b0505.
2. You should be relatively familiar with the different fields as they are similar to DSL set up. Try and decide for yourself what would be appropriate to click on or change. See the back page for the answers assuming you were fitting the same type of hearing aid as before (Starkey).
3. Assuming you have already calibrated the probe tube, insert the probe tube to the appropriate length. Check that the input level is set to 65 dB, that you are on GAIN/SPL mode in VIEW, then click on REUR. 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 vasaline if necessary.
6. Switch off the hearing aid and click on REOR. 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, and click on obtain a REIR (at 65 dB). 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. Check targets at 50, 80 and possibly 90 dB and make the appropriate changes to ensure targets are best meet at all levels.