Interacoustics Affinity2.0 Quick Manuals page 63

Quick Guide –
Introduction
The Real Ear to Coupler Difference (RECD) is a measurement that accounts for the decibel difference across
frequencies between SPL measured in the coupler and the SPL measure in the real ear, produced by the same
transducer generating the same signal. This ensures that information about the patient's occluded ear canal
characteristics is obtained.
Due to the physically smaller size of the ear canals for infants and children compared to adults, and because it
would be very difficult to do real-ear verification on them, the RECD is an important measurement in the
pediatric hearing aid fitting process. It enables clinicians to verify the frequency/gain characteristics of the child's
hearing aid while it is attached to the 2cc BTE coupler, without the need to have the child's ear physically
present. Since children have physically smaller ears than adults, and smaller ears equals higher SPL, not
taking the RECD into account would likely lead to over-amplification. For more information on RECD and the
recommended guidelines for pediatric hearing aid fittings, please refer to the references at the end of this
document.
Measuring the RECD
There are two ways of measuring the RECD: with the patient's ear mould or with the SPL60 RECD probe tip.
Measuring with ear moulds will be a bit more precise than measuring with the SPL probe, however; in situations
where a quick measurement is needed, using the SPL probe will be much quicker than measuring with the ear
mould. In situations where no measurement can be obtained, it is recommended to use age appropriate,
predicted RECD values. Instructions for all three methods are detailed below.
RECD measurement with earmold
Items required:
 2
The Affinity or Callisto™ with Coupler Base

The REM440 software

An REM headset/reference microphones

A probe tube

An ear mould

An RECD tube found in the SPL60 Probe tip set, which will be connected the ear mould tube via a tube-
nipple

2 cc coupler connected to an adaptor for the BTE
Figure 1: Measuring the RECD with an ear mould with Affinity
Item No. 8105091 – 12/2013
RECD with REM440
2
and Callisto™.
Page 1 of 6