Frye FONIX FP40D - Manual (Page 113)

Real-Ear Measurements 105
5.7.5 Checking an aid against a prescription
This procedure allows the operator to reenter data from the client’s initial prescription FOG curve,
so that the actual “custom” hearing aid ordered can be compared and adjusted to the original FOG
Curve when it is received and before the client is scheduled for a real ear fitting. It is assumed that
you have followed the instructions found in Section 5.7.2 and 5.7.4 to generate the client’s initial
prescription FOG and SSPL 90 curves, ordered the custom hearing aid, and saved this data in the
client’s file.
When the ordered hearing aid is received, follow these steps to set up the comparison test proce-
dure.
1. Follow the instructions from Section 5.2 to generate a target using the same fitting rule that
you used in the previous prescription.
2. Press F7 to enter the COUPLER Mode. If you used an average RECD and an average REUR to
generate the 2-cc target, skip to step 6.
3. Press F3 to enter the RECD screen and enter in the client’s measured RECD. F1 will return
you to the Target 2-cc screen. If you didn’t perform an RECD measurement on the client, skip
this step.
4. Press DATA to display the numeric curve data.
5. Use the FREQUENCY and AMPLITUDE knobs to modify the 2-cc target until it matches the
target generated during your client’s last visit.
6. Press F6 to select the source level. You should usually use 50 dB or 60 dB since these are the
amplitudes the manufacturer would have used when testing the hearing aid.
7. Place the newly ordered hearing aid in the test box and set it to full-on gain.
8. Press START/STOP to take the coupler measurement.
9. Adjust and modify the hearing aid to match as closely as possible the 2-cc target.
10. Contact the client for a real ear fitting.
Note: This test procedure can be used to compare a stock, programmable, or a client’s old hearing
aid against the prescribed 2-cc target.
*
Pascoe, David P: Clinical measurements of the auditory dynamic range and their relation to formulas for hearing aid gain.
Hearing Aid Fitting, Theoretical and Practical Views. Ed. Janne Hartvig Jensen. 13th Danavox Symposium 1988