Performing an RECD Measurement

In this short video, Dennis Mistry, BSc (Hons) Audiology, takes you through the steps involved when verifying a hearing aid with a coupler and the Affinity Compact.

You can read the full transcript below.

Introduction

Hello and welcome. This video explains the process required when fitting hearing aids on a coupler using an Affinity Compact.

RECD process

The coupler fitting process involves first of all the selection of your audiometry. Then, choosing the correct target. Third, the measurement of your RECD or selection of an average RECD. Four, how to place the hearing aid in the test box. Five, aided measurements and your target match.

Step 1: Selection of audiometry

In your patient management system, select the patient you wish to fit your hearing aids for and launch your Affinity Suite software. The software will start up in the audiometry screen. Your audiometry is your starting point for your hearing aid fitting, and it should be performed to the best detail to ensure the best fitting and reduce returns of your patient.

You can perform the audiometry from scratch or select the audiometry session that you wish to base your fitting on.

Step 2: Choosing the correct target

On launching the REM module of your software and selecting the test protocol, you will be prompted to select the fitting prescription.

There is a lot of choice surrounding fitting prescriptions, but we recommend choosing NAL or DSL algorithms, as these are both evidence-based targets which give a good starting point to base your fitting around.

Step 3: RECD measurement

Your probe tube calibration process dictates which method of RECD you will perform. Should you wish to use the patient's earmold, then you should select the regular probe method. Should you wish to use the SPL60 probe, then you should use the SPL method.

It's important that you correctly run the tube calibration process as this prepares your system for the further measurements that you'll run at this process. For more information on this, please see this probe tube calibration video.

Run the RECD process and follow the steps on the screen. On running the RECD measurement, the software will guide you first to run the coupler measurement and then the ear measurement according to your chosen method in the calibration setup. Follow the instructions provided in the software.

If you're unable to measure an RECD or wish to use an average RECD value, you can right click on the RECD measurement tab and choose 'show predictive curve'. This matches the patient's criteria that you've chosen in your patient management system and therefore provides the correct age-related curve according to your settings.

Step 4: Placing the hearing aid in the test box

You can now attach your hearing aid to the relevant coupler adapter, placed in the center of the test box with the reference microphone close to the hearing aid microphone without touching. This is your reference point of your test box, and the content should remain in this position for the rest of your measurements.

Different styles of hearing aids can be attached to your coupler using different adapters. The following table summarizes how you should do this.

It's also helpful to use a putty supplied with your system to achieve a good acoustic seal.

Step 5: Aided measurements and target match

You can now close the test box lid, switch on the hearing aid, and begin your fitting. It's advised that you run three different stimuli levels: 65, 50, and 80 dB. This ensures that you're assessing the hearing aid at different levels of intensity.

On running the different stimuli, you should alter the gauge trimmers in your hearing aid software to ensure a good target match. You can use a Delta Values feature in your Affinity Suite to help you with it.

Once the sufficient target match has been achieved at all three levels, it's recommended that you next run a 90 dB pure tone or warble tone. This helps to understand the maximum output of your device so that you can check it doesn't exceed the patient's comfortable loudness levels.

After obtaining all of these measurements, the objective aspect of the fitting has now been completed. You should now place the devices on your patient to counsel them regarding the amplification they're receiving and also to include their preferences within the fitting, which may lead to further fine-tuning.