MedRx Step-by-Step RECD Guide
The Real Ear to Coupler Difference (RECD) is used to simulate real ear measurments by coupler measurements and is useful when fitting children or difficult to fit patients.
Terry Ross is Vice President of MedRx, Inc., a leading global manufacturer of PC-based diagnostic and testing instrumentation. He has over 35 years of executive management experience in the hearing care industry. He is responsible for directing the global sales and distribution activities for MedRx.
Other Articles by Terry Ross:
by Terry Ross
Vice President, MedRx, Inc.
Estimates from several independent studies indicate that up to 6 per 1,000 newborns have some level of hearing loss and there is growing evidence that latent losses go undetected in a large percentage of pediatrics patients under the age of 3 years old. Testing for newborns has been established through otoacoustic emissions testing to identify early loss, however, some congenital losses may not become evident until later in childhood. Fitting these children and programming with hearing instruments can be, at best, challenging. The good news is that there are protocols and hardware from MedRx that can address this challenge.
The need to achieve greater fitting accuracy and selecting appropriate amplification has led to the development of RECD (REAL-EAR to Couple Difference) measurements. RECD measurements have gained popularity in many practices, allowing hearing aids to be pre-programmed prior to fitting. Remember, infants and children have much smaller ear canal volumes which introduces sizable variation in the amplification process
The RECD is simply the difference in dB across frequency, between the SPL measured in a 2-cc coupler (available from MedRx) and the SPL measured in the patient’s ear. This difference measure is also used in some amplification fitting protocols (e.g., DSL [i/o], NAL-NL1) to capture the effects of the patient’s occluded ear canal acoustics. Obtaining the patient’s individual measurement is helpful in converting HL to ear canal SPL to accurately select an appropriate hearing instrument. It can also be used in calculating the predicted REAR (Real-Ear Aided Response) which is used when verifying hearing aids in a coupler.