How to Use AutoFit
www.siemens.com
Marjolijn Kindt
Abstract:
AutoFit™ is an optional feature in Connexx™ 7.1 that automatically
provides the Hearing Care Professional (HCP) with an optimized realear insertion gain (REIG) setting immediately after first fit, without the
need for the HCP to manually match targets. This paper describes
how to perform quick match-to-target fittings using AutoFit.
How-to Use AutoFit
1. Introduction
AutoFit™ is an optional feature in Connexx™ 7.1 that automatically provides the Hearing Care
Professional (HCP) with an optimized real-ear insertion gain (REIG) setting immediately after
first fit, without the need for the HCP to manually match targets. AutoFit significantly reduces
real-ear verification time for traditional prescriptive targets (e.g. NAL-NL2 or DSL5), as well as
offering the ability to verify to Siemens’ proprietary target; micon™ fit, in the real ear.
AutoFit is compatible with all levels of Siemens hearing instruments supported by Connexx
7.1. It is available with compatible real-ear measurement (REM) systems (currently Unity™ 2
and MedRX AVANT REM, and MedRX AVANT REM+) and is performed within Connexx without
the need to initialize independent REM modules. Compared with previous versions, the
Connexx 7.1 AutoFit workflow is simplified, more efficient, and is quicker without compromising accuracy.
When using AutoFit, the patient and hardware set-up is similar to what is used for traditional
real-ear measurements. And like traditional real-ear measurements and match-to-target procedures, the success of AutoFit also depends on the correct placement of the tip of the probemicrophone tube, as well as the patient and speaker arrangement.
2. Procedure
To access AutoFit, connect and read out the hearing instruments. It is vital that the appropriate acoustical parameters are entered prior to commencing AutoFit (Figure 1). This includes
coupling type (Life tip, dome or mold), earhook, tubing, and vent size. At this point, the HCP
can perform an InSituGram™ if no pure-tone audiogram is available (Figure 2). Please note
that AutoFit will take into account many real-ear effects.
Before starting the AutoFit procedure, the desired prescription formula and user experience
level should be selected. There is a choice of NAL-NL1, NAL-NL2, DSL-v5 and micon™ fit (Figure 3).
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How-to Use AutoFit
Figure 1: The First Fit page in Connexx 7 where the appropriate acoustical parameters need to be
entered. Note that these include Coupling Type, Mold Type and Venting in this example (see items
circled in red).
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How-to Use AutoFit
Figure 2: The InSituGram module can be accessed from this page; and also note in the lower right
corner the tab for AutoFit (see items circled in red).
Figure 3: Select the desired fitting formula and experience level. (See items circled in red).
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How-to Use AutoFit
2.1.
Probe-Tube Calibration
To open the AutoFit window, click on “Autofit”. You will find this on the bottom right corner
of the First Fit page. Importantly, this tab only will appear if compatible hardware is installed
on the system and the hearing instruments are connected. The AutoFit procedure requires 3
steps to be fulfilled; these are displayed in 3 tabs across the bottom of the AutoFit screen:
Tube Calibration, REUG and AutoFit.
Figure 4: Probe-Tube calibration window under the AutoFit page (see red arrow at lower right).
Note that there are two “Start” buttons, as some probe systems have separate probe-mic assemblies for the right and left ear. Also shown on this screen shot are the three tabs for “Tube Calibration,” “REUG,” and “Autofit” (see lower horizontal bars).
The first step is a probe-tube calibration, which is necessary before any real-ear measurement
is conducted (see lower left tab on Figure 4). Once this screen has been accessed, click on
“Start” to initiate the measurement. Follow instructions shown on the Connexx screen regarding how to run the calibration. Connexx will automatically check if the calibration is within
the tolerable range. If you will be using a different probe assembly for the right and left ear,
then both will need to be calibrated. Once the probe-tube calibration is finished, a check
mark will appear in the side-identifying box. Importantly, however, if the probe tube is
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How-to Use AutoFit
changed during the testing (e.g., because it becomes plugged), then this calibration procedure will need to be repeated.
Figure 5: Tube calibration window when the calibration has been completed for both ears. Observe that there now is a check for Tube Calibration in the lower left corner.
2.2.
Real-Ear Unaided Gain (REUG)
Because AutoFit is designed for the hearing instrument to match to target in the real-ear, a
Real-ear Unaided Gain (REUG) measurement needs to be first carried out. To conduct the
REUG:
The patient should be seated directly in front of the probe-system loudspeaker, at a
distance of one meter, at a 0 degree horizontal and vertical azimuth.
The probe tube should be placed in the open ear canal so that the tip of the tube is
approximately 5 mm from the tympanic membrane. This can be approximated by using a marker on the tube set at 30mm, and placing this marker at the inter-tragal
notch of the pinna.
The REUG testing is conducted with the ear open (no hearing aid or earmold in place).
Once the patient and the probe tube have been positioned correctly, click on “Start” to initiate
this process. What is shown in Figure 6 is the REUG of a sample patient. Once the measured
REUG is displayed, a check mark appears in the lower left side identifying box (see red circle
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How-to Use AutoFit
on Figure 6). If the REUG measurement does not appear appropriate (e.g., patient moved,
probe tube not deep enough, etc), it is possible to re-measure by repeating the process (make
the appropriate corrections and click on “Start” again).
In bilateral fittings, it is of course necessary to measure the REUG of each ear independently.
Connexx will guide you through the workflow accordingly, which will start with the right ear.
According to your probe-mic assembly, these measurements can be performed with either
one probe tube for both ears or two individual probe tubes.
Figure 6: REUG window under the AutoFit. Shown here is a completed REUG measurement for a
sample patient. Use the “start” buttons to initiate right and left side measurements respectively
and note the check mark in the side identifying box on the bottom of the window once a measurement has been recorded.
2.3.
Real-Ear Insertion Gain (REIG)
Once the REUG measurement has been carried out - with the probe microphone still appropriately placed in the ear - carefully fit the hearing instrument. Clicking on the third tab “AutoFit,” the gain targets for the prescriptive formula selected previously will be displayed for
soft, medium and loud inputs.
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How-to Use AutoFit
Figure 7: AutoFit fit screen displaying the prescriptive targets for REIG; micon fit “Experienced” was
selected for this sample patient.
To begin the procedure, click on “Start AutoFit”. The MedRX or Unity 2 speaker then emits a
broadband LTASS signal at 65dB SPL, which allows the AutoFit algorithm to first determine
the current gain in the wearer’s ear, and then where required, automatically adjust the gain
to match the selected prescriptive target for the 65 dB SPL input level. The other two curves
(for soft and loud inputs) are displayed as a reference. The results of this automatic fit-totarget for this patient are displayed in Figure 8. In this example, we are using a patient who
was being fitted to NAL-NL2. When AutoFit is completed, the HCP is given the option of programming the AutoFit settings into the hearing instruments by leaving the “Keep AutoFit result” tick box checked, or restoring the instruments to the original settings (before performing
AutoFit) by un-checking it.
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How-to Use AutoFit
Figure 8: This is an example of a patient who was being fitted to NAl-NL2 prescriptive targets,
“Experience User.” After AutoFit has completed the match-to-target automatic adjustments, the
HCP has the option to keep or discard the new gain settings via the check box (red oval).
The complete AutoFit procedure is very efficient (about 3-4 minutes of test time) and can save
HCP a considerable amount of time compared to manually matching to target during real-ear
verification (Hinchcliffe, 2012).
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How-to Use AutoFit
3. Device configuration
There are several REM hardware set-up options, some of which depend on the number of
probe modules that are used. Some probe-mic systems offer the option of having two different probe-assemblies, so that a different module can be used for the right and left ear. In
many cases, even when two assemblies are available, the HCP finds it more convenient and
less confusing to use the same probe assembly for both ears. In order to select the desired
option, open the User Preferences tab, select “Devices” and click on REM Device (See Figure
9).
Figure 9: Device configuration. Select "devices" and "REM Device" to access configuration.
Select your preferred REM device and the appropriate probe module setting, corresponding to
your system and preferences, click OK, and these settings will be saved as default.
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How-to Use AutoFit
Figure 10: Select your preferred configuration settings.
4. Summary
AutoFit is an option within Connexx™ 7.1 which automatically adjusts the frequency response
of a hearing instrument to match prescriptive gain targets within 3-4 minutes, thereby significantly reducing the time required in fitting hearing instruments to prescriptive targets. It also
allows the hearing care professional to perform real-ear measurements without initializing the
Real-Ear Measurement software separately. To summarize, this efficient AutoFit procedure
can be easily performed in a few simple steps:
Step 1: Seat patient in front of probe-mic system, approximately one meter from loudspeaker
located at a 0 degree horizontal and vertical azimuth
Step 2: Connect and detect the hearing instrument, select new fitting
Step 3: Enter acoustical parameters, perform InSituGram™ if required and select desired
fitting formula
Step 4: Calibrate probe tube as described
Step 5: Conduct the REUG
Step 6: Place instrument on the ear
Step 7: Perform AutoFit; observe resulting REIG
Step 8: Accept changes and close dialogue
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How-to Use AutoFit
5. References
Hinchcliffe, S. (2012). Can AutoFit REMs improve Workflow? Poster presented at the conference of the British Academy of Audiology (BAA).
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