The purpose of this document is to provide a quick guide for the Binaural REM feature found in the REM440 Real-Ear Measurement module in the Affinity 2.0 and Callisto™ Suites. This Quick Guide will focus on the method and order of performing measurements using this function.
Interacoustics are pleased to announce the availability of a Binaural REM feature in the Affinity 2.0 and Callisto™ Suites. This feature will allow you to perform Real Ear Measures in a much faster procedure and allow you to view the activity in each ear simultaneously.
Enter/Select an audiogram from Noah or from the AUD module. If no audiogram is entered or selected, no targets will be displayed.
To enable Binaural REM measurements in the REM module you will need to Right click on the ear selector icon. This will then show a binaural icon and a popup to alert the user when using this function.
Please note: when running measurements of this type you will only be using one reference microphone to monitor the signal from the speaker. This is the right microphone by default but it can be swapped to the left microphone by using the ‘use opposite reference microphone’ button.
It is also essential that the position of the patient in relation to the REM speaker is maintained at 0° as this will ensure that the same signal intensity is reaching each ear as they are equal distance from the speaker.
Connect probe tubes to the REM reference microphones.
Click on the Tube Calibration button and follow the instructions on the screen, this process ensures that the probe tube is made acoustically invisible – enabling an effective display of the actual gain achieved at the tympanic membrane by the hearing aid.
On running the calibration you will notice that in Binaural mode there is an automated procedure to calibrate both Left and Right REM tubes sequentially, without having to manually start each individually.
Position the patient approximately 0.5 metres from the REM loudspeaker.
Perform otoscopy to ensure the ear canal is clear.
Snap the REM headsets on the REM headband and place on patient’s ear.
Choose a relevant protocol to perform your verification; in this example the default ‘Adult Insertion Gain’ protocol has been used.
Note: For this example, an Insertion Gain method has been used to demonstrate the Binaural REM feature, however the feature is also compatible with protocols which perform this measurement in an Aided Response method.
Once you have chosen your protocol please configure your fitting prescription settings as per your fitting.
Place the REM tubes inside the patient’s ears and aim to use a marker of roughly 27mm on the probe tubes. This helps to get the open end of the tube in an optimum recording position (BSA, 2007).
Begin by running the REUR measurement, this is looking at the natural acoustics of your patients ear canals, it is performed with nothing in the patients ear canals apart from the probe tubes. Your response should peak around 2-3 kHz for a normal adult response (BSA, 2007). The shape of this measurement can also be used as a quality criteria for your probe placement, the measurement should intersect the
Horizontal axis (x-axis) at 6khz and must not be more negative than -5dB (BSA, 2007 & ISO, 2003).
Please place the hearing devices into your patient’s ears along with the probe tubes for the following measurements.
You will notice that there is a target in these measurements; in the next step it is shown how you can amend the output of the patient’s hearing devices to meet these targets.
Note: the default view for the Binaural REM feature is to have the left and right aided measure displayed side-by-side. However this can be swapped to an on-top comparison by pressing the button shown below, there is an example of this view below.
Note: Percentile analysis can also be performed in Binaural REM, you just need to enable this setting within your Aided Response measurements protocol. Once enabled, the test screen will show you the percentile range for your output, as shown below.
Note: Using this feature will remove your previous target allocation (i.e. NAL-NL2, DSLmi/o etc) from the opposite ear side, which you have not provided custom values for, because we cannot allow different prescription methods to be used on different ears independently.
Note: Binaural REM can also be used when fitting Open Fit type hearing aids. All this requires is for the ‘Open Fit Calibration’ to be run following the REUR measurement for the signal(s) you wish to use for the following measurements.
Note: Binaural REM can only be used with stimuli which do not require active referencing during the measurement. Therefore Binaural REM is not suitable for measurement with Warble Tone, Pink Noise, Random Noise, Pure tone and Narrowband Noise.
For a more detailed description of how to use the REM440 module, please refer to the following documents:
BSA (2007). Guidance on the use of Real Ear Measurement to verify the fitting of digital signal processing hearing aids. Reading, British Society of Audiology.
BS ISO 12124 (2001). Acoustics: Procedures for the Measurement of real-ear acoustical characteristics of hearing aids. Geneva, International Standards Organisation.