Verification with Visible Speech Mapping. Interacoustics Equinox 2.0, affinity 2.0
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Affinity 2.0 Additional Information Page 252
2.11 Verification with Visible Speech Mapping
2.11.1 Considerations before you begin
Visible Speech Mapping can be run side by side with the relevant fitting software. After fitting the hearing aid,
Visible Speech Mapping can be used to verify if the client’s speech area is amplified sufficiently using these stimuli: ISTS, Male Speech, or Female Speech.
Visible Speech Mapping can be used as a verification measure and does therefore not necessarily need to be performed together with an Insertion Gain measurement. Visible Speech Mapping provides a precise measure of the SPL at the ear drum matched up to a fitting target selected by the clinician.
The following description provides an introduction to the clinical use of Visible Speech Mapping. The system can be used in all sorts of ways. Clients have very different needs and this section demonstrates the options offered by the system.
2.11.2 Visible Speech Mapping (in ear mode)
1) Open the REM440 module.
2) Select a test protocol that includes Visible Speech Mapping in the List of Protocols .
3) Explain the procedure to the client.
4) Perform otoscopic examination.
5) Mount the probe tube on the in-situ headset and place it on the client who should be seated ½-1 meters from the speaker.
Ensure that the probe tubes are calibrated before placing them in the ear canal (see section 0 about
tube calibration).
6) Carefully insert the hearing aid without moving the probe tube. Ensure that the instruments are switched on.
7) If fitting an open hearing aid solution, perform Calibrate for open fit
8) Click on the Visible Speech Mapping button if it is not already marked automatically.
Note: A right click on Visible Speech Mapping button allows you to enter the Settings menu or
Change colour of the curve..
9) Check that the information about client, fitting prescription and hearing aid to the right are correct by pressing Show fitting prescription and test information .
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10) Ensure that the correct Ear is selected .
If you wish to measure on both ears right click on the ear icon
11) Choose the preferred Stimulus in the corresponding dropdown list
Male Speech, Female, Speech, and ISTS are recommended.
Note the option to use Live Voice .
If you have done Calibrate for open fit only the signals used for this calibration are available in the stimulus selection dropdown
.
12) Select input level using the Input level slider
13) Click START and the Visible Speech Mapping will be performed.
Ensure that the hearing aids are switched on and that the room is quiet while the curve is obtained.
Mode to compare to the hearing aid manufacturer’s software .
2.11.3 Visible Speech Mapping (in coupler mode/test box mode)
1) Open the REM440 module.
2) Select a test protocol that includes Visible Speech Mapping and RECD in the List of Protocols .
3) Explain the procedure to the client/relatives.
4) Perform otoscopic examination.
5) Perform the RECD with the client’s own ear mould or the SPL probe (see section 0). Also note the
option to select a predicted RECD (see section 0).
6) Place the hearing aid in the test box as shown below and ensure that it is switched on.
It is important that the reference microphone is placed in the same acoustical point as the microphone in the hearing aid. The placement may therefore differ a little depending on the hearing aid you are testing.
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7) Click on the Visible Speech Mapping button if it is not already marked automatically.
Note: A right click on Visible Speech Mapping button allows you to enter the Settings menu or
Change colour of the curve.
8) Check that the information about client, fitting prescription and hearing aid to the right are correct by pressing Show fitting prescription and test information .
9) Ensure that the correct Ear is selected
Note that Both ears is not an option for coupler mode
.
10) Choose the preferred Stimulus in the corresponding dropdown list
Male Speech, Female, Speech, and ISTS are recommended.
Note the option to use Live Voice . In this case the test box lid should be left open.
.
11) Select input level using the Input level slider
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12) Click START and the Visible Speech Mapping will be performed.
Ensure that the hearing aids are switched on and that the room is quiet while the curve is obtained. mode to compare to the hearing aid manufacturers’ software .
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2.12 Visual Tools for Counseling and Verification
2.12.1 Percentile Analysis
The Percentile Analysis can be added in the REM440 setup (see section 0.1)
The Percentile Analysis is implemented according to the IEC 60118-15 standard.
By default the 30th, 65 th , and 99th percentile are selected. These percentiles are calculated based on an FFT analysis of 100 measurements.
The 30th percentile (indicated in blue shading) is the sound pressure level below which 30% of the measured levels are found for each frequency. The remaining 70% of the measured sound pressure levels are higher. The 30th percentile thereby represents the lower valleys or the soft components of the speech signal. This helps you ensure that even the soft valleys are above thresholds.
The 99th percentile (indicated in green shading) is the sound pressure level below which 99% of the measured levels are found for each frequency. The 99th percentile may be interpreted as a peak indicator which helps to ensure that no peaks come too close to the MPO and/or UCL’s. In other words the 99 th percentile represents the loud components of the speech signal.
Together the 30th and 99th percentile provides an “area of audibility”. The 65th percentile serves as a borderline between the 30th and 99th percentiles and is visually represented at the point where the blue and green areas meet. The 65 th percentile represents the median whereas the measurement is the average of the FFT analysis of the 100 measurements.
Picture note: On this illustration the percentile analysis reveals important information about the hearing aid fitting. At 3-4 kHz the peaks of the signal (the 99 th percentile) are too close to the UCL. However, we also see that even though we cannot fit above thresholds the client is still getting some speech information in this frequency area since the 99 th percentile is above thresholds. In the low frequency area we can see that even though the curve is above threshold and we match target, the lower valleys (30 th percentile) are not above thresholds and the client is thereby missing information.
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2.12.2 Display Peaks and Valleys
Display peaks and valleys can be added in the REM440 setup (see section 0)
When Display peak s and valleys is ticked you will have the view illustrated below. The peaks and valleys are shaped according to the LTASS and are the same as the 30 th and 99 th percentile in the Percentile Analysis
2.12.3 Show Examples
Tick Show Examples and show the speech area together with sound examples from real life like a dog barking or the wind rustling leaves.
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2.12.4 Speech Intelligibility Index
As a supporting feature the SII (Speech Intelligibility Index) indicates improved audibility expressed in a percent on the aided display.
SII is a method for computing a physical measure of the intelligibility of speech. The method is based on results of the speech perception tests in a given group of talkers and listeners. The SII is calculated from acoustical measurements of speech and noise, taking into account the level of the distortion factor at standard speech level. ( www.sii.to
)
2.12.5 Speech Spectrum
Add a Speech spectrum view by right clicking on the graph. This is useful when explaining the importance of speech audibility and/or language development.
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2.12.6 Dynamic Range View
The hearing thresholds converted to SPL and the UCLs provide a dynamic range view. This provides the option to show that speech sounds are above thresholds and are within the area where the client can hear
(but without being uncomfortably loud).
You can demonstrate the reason why the relatives/loved ones do not need a hearing aid, but the client does by pointing out the Normal Hearing thresholds marked in red.
Perhaps present a loud input or speak loudly to visualise the compression of sounds in the hearing aid and point out that peaks in amplified sound never go beyond the MPO and UCLs.
Dynamic range
Normal hearing thresholds
2.12.7 Aided versus Unaided
If the client/relatives have no experience with hearing aids, it may be a good idea to focus on the difference between the aided and unaided. This helps to demonstrate the hearing aid benefit effect and the importance of wearing instruments. If fitting children this also gives a good basis for discussing language development.
Note that the unaided graph shows the dB SPL at the reference microphone and the aided graph shows the
SPL at the ear drum.
.
2.13
Affinity 2.0 Additional Information Page 260
2.13 Visible Speech Mapping Settings
Visible Speech Mapping with individual settings can be added to a test protocol the same way as other REM
1) Enter the REM440 setup ( Menu/Setup/REM440 setup ) and add Visible Speech Mapping to the test protocol.
2) Ensure that Visible Speech Mapping is marked in the left hand side of the screen. The name of the test will then appear in the Name of selected test section.
Note the option to write a new name for the test in this section (e.g. “Visible Speech Mapping 65 dB”)
3) Stimulus selection
Input Level: Set the input level using the slider.
Preconditioning
: This is relevant when using broadband signals such as ISTS (see section 0 for
details). Select a time using the slider.
Stimulus type: Select a stimulus using the dropdown list. Note that Live Voice is also an option.
However, this is not a calibrated test signal and should therefore only be used for counselling purposes.
Smoothing Index: You have the option to smooth the measured curve using the slider (see
section 0 for details). The higher the index number selected the more smoothing is applied.
Continuous: This check box allows you to make the measurement ongoing rather than a single sweep. This may, however, also be done in the front screen using the continuous button:
When continuous is ticked, the stimulus and recording will continue until you press the STOP button. This can be practical for example when using Live Voice.
Start Frequency and Stop Frequency: Select the preferred frequencies using the sliders. These may for example be set so that they correspond with the hearing aid gain handles (e.g. if the hearing aid goes up to 8000 Hz there is no reason to measure beyond this frequency).
Sweep delays: This is relevant if Continuous measurement is selected for Pure Tone or Warble
Tone. In this case sweep delays (in milliseconds) may be entered between the individual
sweeps (see section 0 for details).
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Measurement time (in seconds): Duration for the measurement can be set using the slider. This is only relevant for broad band signals. A number of seconds can freely be selected between 1 and 1200. By default the measurement time is the same for all signals.
Instructions: This allows for adding picture instructions. If the box is ticked an instruction box explaining how to perform the measurement will appear upon pressing START .
4) Display:
Display Peak s and Valleys : This is relevant when using a broad band signal. When ticking the check box the REM440 will show the measured maximum and minimum area in the speech spectrum over time (5 seconds) on screen. The measurement is independent of the selected measurement time.
1/3 octave and overlapping time window: For speech-like signals, the signal is converted into an
FFT and then sampled. The clock frequency of the Affinity is 44100 Hz and we do 1024 samples per second. This means that the time period for each sample is 23 ms.
Percentiles for full measurement: ac tivate this box if you want to see the intensity components in different shaded percentile sections – these are customisable and will show the output as a shaded range on the graph.
Show dynamic compression ratio: Enabling this feature will display the dynamic compression ratios when the 1/3 octave and overlapping time windows option is enabled .
Set settings to IEC 60118-15 : use this button in order to set the measurement settings according to the IEC 60118-15 standard
this will amend the settings mentioned above to meet this configuration description.
Show target:
This will add the fitting target from the screen or REM440 setup (see section 2.6.4)
by default.
Show SII:
This will add the Speech Intelligibility Index to the graph (see section 0)
Show MPO: This will remove the MPO when using the DSL mi/o fitting prescription in Response view.
Percentile analysis:
Here percentiles can be selected for the percentile analysis (see section 0).
The recommended percentiles are 30 th , 65 th and 99 th . When Display peak s and valleys is ticked it is NOT possible to set percentiles under Percentile analysis.
5) Recording Method:
Resolution (of frequency): Select the preferred resolution in the dropdown. The higher the resolution the slower the measurement.
Keep in mind that 1/3 is what is used in many hearing aid manufacturers software. If the curve is to be compared to this you may consider choosing this resolution. Also note that when using a broad band signal the dropdown list will be greyed out and automatically choose FFT. This makes the distance between frequency bins 43 Hz which ensures precision in the measurement.
6) Colour:
Select a colour for the Right and Left curve.
Press each of the buttons to have the custom colour selection below. Choose the desired colour by clicking on it and press OK .
Note the option to Define Custom Colours and get a more extensive selection. When having found the exact colour, press Add to Custom Colours.
45 For detailed information, please refer to the IEC 60118-15 standard.
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2.14 FAQ
Question:
After I accidently disconnected the USB my system behaves strangely – what could be the cause?
Answer:
If the USB is disconnected during testing the software suite should be restarted. Otherwise the connection may be affected and testing may be compromised.
Question:
There is no target on my screen. What could be the reason?
Answer:
1. Please check that you have typed in or selected an audiogram in the AUD tab. If no audiogram is present the system cannot calculate a target
2. Please check that the transducer you have selected in the Fitting prescription options corresponds to the transducer used for the selected audiogram
3. For NAL-NL1/NAL-NL2 please make sure that all important frequencies are included in the audiogram
(e.g. 500, 1000, 2000, and 4000 Hz). This also corresponds for Bone conduction targets where you need the BC values.
Question:
What is the broad band sound before some measurements and can it be switched off?
Answer:
The broad band noise that you hear before a measurement starts is presented ONLY when using broad band test stimuli or wave files. This type signals must thus be preceded by this preconditioning and calibration and it cannot be switched off. During the calibration/preconditioning the distance between the loudspeaker and the reference microphone on the in situ headset is measured. This ensures a precise measurement. If this calibration does not take place you cannot be sure if the correct input level enters the ear canal and as a result you are at risk of measuring erroneous curve.
Question:
I have seen that when you perform REAR in Affinity 2.0
REM440 using DSL mi/o fitting prescription the
REAR target change with the choice of stimulus selection (much lower target with ISTS compared to
REAR target with warble or pure tone). However, REIG target remains the same whatever stimulus had been chosen. Would you please send me some information/comment about that?
Answer:
The REIG (pure hearing aid gain) is the same regardless of what stimulus you use. This is because the
REIG is a calculation and not a measurement (REAR – REUR = REIG). The result of the calculation will be the same regardless of whether it is REAR (ISTS) – REUR (ISTS) or REAR (Warble) – REUR (Warble).
Even though the REAR (ISTS) and REAR (Warble) are very different, this difference is also reflected in the
REUR (ISTS) and REUR (Warble). Thus, the result is the same.
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Question:
What kind of stimulus does Interacoustics recommend to be used and in different situations?
Answer:
Choosing the correct stimuli for the purpose is extremely important as it is the basis of a good measurement with a valid result. Digital hearing aids automatically adjust the amplification depending on the input. This capacity, however, cannot be reflected in a real-ear measurement unless a realistic and dynamic test stimulus like speech is used (Fabry 2004).
Using Tone Stimuli
For many years pure tones (sinusoids)/warble tones were the primary signals used for real-ear as well as coupler verification. Tone signals are “simple” signals and only one frequency is presented at the time.
Therefore, real-ear measurements performed with tone signals do not reflect advanced signal processing where frequencies interact (Kuk & Ludvigsen 2003).
Using Speech Stimuli/ISTS
Speech is likely to be most important signal to the hearing aid user in his or her daily life. Therefore, if you wish to verify if speech sounds are audible there is no better stimulus than speech. When using a speech signal the hearing aid will also stand its test since speech has the challenge of changing quickly in amplitude, frequency, and phase.
ISTS (International Speech Test Signal) is an internationally recognized test signal. It was created based on the need for a standard test stimulus that included all the relevant properties of speech and allowed for reproducible measurement conditions. It is created from natural recordings of speech which is non-intelligible due to remixing and segmentation. The signal reflects a female speaker for six different mother tongues
(American English, Arabic, Chinese, French, German, and Spanish) reading “The north wind and the sun”.
The ISTS is shaped according to the LTASS (Long Term Average Speech Spectrum) standards (Holube et al. 2007).
Using Composite Signals/ICRA
Artificial signals without significant variation in intensity and frequency can also be used in order to test hearing aids in the frequencies of speech. These are called speech spectrum shaped composite signals and have the same long-term spectral characteristics as speech.
The advantages in such signals are that you are able to test many frequencies in a short time and that interactions among frequencies can be tested.
The ICRA signals (International Collegium of Rehabilitative Audiology) are examples of composite signals.
They are a group of test signals developed by the HACTES group (Hearing Aid Clinical Test Environment
Standardisation) in order to be able to do reliable measurements on non-linear digital hearing aids. They represent a number of speech weighted noise signals composed with spectral and temporal characteristics similar to those that are found in speech signals and babble noise. (www.icra.nu).
What Stimulus to choose?
Which stimulus to select depends on your focus and the individual patient.
If for example seeing a patient who complains about not being able to hear his wife, you may want to try the
ISTS.
If the patient is having trouble when more than one person is speaking, the ICRA 6pbl (or one of the other signals with multiple people speaking) may be selected.
If you wish to look at the effects of a noise reduction, a noise signal such as Pink Noise may be the appropriate choice.
Note that your choice has an impact on your result as illustrated below:
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Warble Tone
Pink Noise
ICRA 6pbl
ISTS
References:
Fabry D. (2004) Real Ear Measurements and Digital Hearing Aids: Realities, Myths, and Measurement
Techniques. Phonak Focus no. 32. ( www.phonak.com
)
Kuk, F & Ludvigsen, C. (2003) Changing with Times: Choice of Stimuli for Hearing Aid Verification. Hearing
Review, August 2003.
Holube, I & EHIMA-ISMADHA working group (2006) Short description of the International Speech Test
Signal (ISTS). Center of Competence HörTech and Institute of Hearing Technology and Audiology,
Oldenburg, Germany http://www.icra.nu/Prod_Noise.html
Affinity 2.0 Additional Information
Question:
When I do the REUR with an ICRA or ISTS I get a pretty flat curve:
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When I do the REUR with a warble tone I get, what I think is a correct curve:
What is the reason for this difference?
Answer:
With response measurements you are measuring the ear canal + the signal you are using. This means that you have two components affecting the result.
When using pure tones the signal has the same energy at each frequency. Then you get an REUR the shape similar to the lower image above. However, your curves above are correct as well. When you are using a broad band signal the energy is not the same at each frequency and this affects the response measure! This can be seen from your own examples above.
The REUG does not take into account the test signal. This is why you don’t see a similar difference for the
REUG
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Question:
When I do the REUG I have to do the REAG and then I don’t see the REIG. That means that I’m not going to use this setup. I can’t choose the REIG without the REUR according to the program.
Answer:
In the Affinity you don’t have to do the REAG/REAR to see the REIG. When you have done the REUR the system automatically knows that you need the REAR to calculate the REIG. When you have measured the
REUR and go to REIG the system will perform the REAR in the background (without showing it on screen), in order to calculate the REIG.
NOTE: The Affinity Suite demands that you do the REUR to calculate the REIG. The REIG can only be selected as part of the protocol if REUR is also a part of it.
Question:
How is the Monitor/External sound features used?
Answer:
Monitor: If you wish to listen to the amplified stimulus through a monitor.
1. Connect a monitor speaker/headset to the monitor output on the hardware.
2. Tick the Monitor check box.
3. Use the slider to turn the sound level up and down.
Note that the sound from the monitor may be very soft (compared to the audiometry monitoring). It is louder for audiometry because the audiometric equipment is producing the signal that is monitored. In REM440 the hearing instrument produces the monitored signal meaning that it cannot be controlled by the equipment.
However, if you have an active speaker it will be louder.
External sound: You can present an external sound through, for example, a CD player if you have a piece of music/speech you wish to use. This may have a strong effect for counseling purposes.
1. Connect the CD player to the CD1 input on the hardware.
2. Press START in the software and then tick the External sound check box. The external sound will then play together with the signal.
3. Use the slider to turn the sound level up and down.
Note that in Visible Speech Mapping you can select Live Voice and then play an external sound. This means that you will have the external sound alone with nothing (except from your own voice/environment) interfering.
Question:
I did the calibration for open fit with the ISTS signal and the measurement. The Affinity only did the calibration sound followed by a really short stimulus presentation. Furthermore the curve looks strange. Is this how it should be?
Answer:
Yes, this is perfectly normal. The system only needs the calibration signal in order to take into account the open fit. It does not matter what is shown on the screen. The measurement is still correct.
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Question:
In Visible Speech Mapping what is the purpose of percentile analysis?
Answer:
The Percentile Analysis implemented according to the IEC 60118-15 standard.
By default the 30th, 65 th , and 99th percentile are selected. These percentiles are calculated based on an FFT analysis of 100 measurements.
The 30th percentile (indicated in blue shading) is the sound pressure level below which 30% of the measured levels are found for each frequency. The remaining 70% of the measured sound pressure levels are higher. The 30th percentile thereby represents the lower valleys or the soft components of the speech signal. This helps you ensure that even the soft valleys are above thresholds.
The 99th percentile (indicated in green shading) is the sound pressure level below which 99% of the measured levels are found for each frequency. The 99th percentile may be interpreted as a peak indicator which helps to ensure that no peaks come too close to MPO and UCL. In other words the 99 th percentile represents the loud components of the speech signal.
Together the 30th and 99th percentile provides an “area of audibility”. The 65th percentile serves as a borderline between the 30th and 99th percentiles and is visually represented at the point where the blue and green areas meet. The 65 th percentile represents the median whereas the measurement is the average of the FFT analysis of the 100 measurements.
Picture note: On this illustration the percentile analysis reveals important information about the hearing aid fitting. At
3-4 kHz the peaks of the signal (the 99 th percentile) are too close to the UCL.
However, we also see that even though we cannot fit above thresholds the patient is still getting some speech information in this frequency area since the 99 th percentile is above thresholds. In the low frequency area we can seen that even though the
99% higher peaks
30% lower valleys
curve is above threshold and we match target, the lower valleys (30 th percentile) are not above thresholds and the patient is thereby missing information.
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2.15 Appendix 1
2.16 The REM440 Test Signal Characteristics
Pure Tone frequency accuracy is ±1%. Crest factor is 3 dB.
Warble Tone frequency accuracy is ±1%, warble frequency 0 100 Hz and intensity 0 10%, sine wave frequency modulation. Crest factor is 3 dB.
Random Noise is a noise with a linear spectrum measured with an FFT or a 3 dB drop per octave measured with a 1/3 octave filter.
Pseudo random noise . Is a semi-broad-band noise produced from random noise weighted with a 2nd order
200 Hz high pass filter and a 1st order 900 Hz low pass filter as described in the ANSI S3.42 -1992 standard.
Crest factor is 10 dB.
Chirp . Is a linear frequency sweep from 100 to 10 kHz in 23 mS = one FFT measuring. The amplitude is constant during the sweep. Crest factor = 3 dB.
Band limited white noise is a random noise signal band limited by 12 kHz 2. order low pass filter. Crest factor is 9 dB.
ISTS is “for analyzing the processing of speech by a hearing aid, a standard test signal is necessary which allows for reproducible measurement conditions and which features all or most relevant properties of natural speech. Those properties are e.g. the modulation spectrum and the fundamental frequency as well as its harmonics. Existing artificial signals fulfill these requirements inadequately and recordings from natural speak ers represent only one language and are therefore not internationally applicable. Therefore, the
European Hearing Instrument Manufacturing Association (EHIMA) has set up the ISMADHA work ing group and has initiated this project resulting in an International Speech Test Signal (ISTS). The ISTS is based on natural recordings but is largely non-intelligible because of segmentation and remixing. The intention is to include this test signal with a new measurement method for a new hearing aid standard” (Holube et al.
2006).
PinkNoise is a noise with a linear spectrum measured with a 1/3 octave filter or a 3 dB rise per octave measured with an FFT.
ICRA Noise:
ICRA: urgnmn
Unmodulated random Gaussian noise - Male weighted - Normal effort - Level Ref. Crest factor = 13 dB.
ICRA: urgnmr
Unmodulated random Gaussian noise - Male weighted - Raised effort - Level Ref+5.7dB. Crest factor
= 14 dB.
ICRA: urgnml
Unmodulated random Gaussian noise - Male weighted - Loud effort - Level Ref+12.1 dB. Crest factor
= 14 dB.
ICRA: 3bsmnfn
3 Band speech modulated noise (3bSMN) - Female weighted - Normal effort - Level Ref. Crest factor
= 27 dB.
ICRA: 3bsmnmn
3 Band speech modulated noise (3bSMN) - Male weighted - Normal effort - Level Ref. Crest factor =
27 dB.
ICRA: 2pb1f1mn
2 persons babble, 1female 3bSMN + 1 male 2bSMN - Idealized - Normal effort - Level Ref + 3dB.
Crest factor = 24 dB.
ICRA: 6pbn
6 persons babble, 1f+1m+2f(-6db)+2m(-6dB), all 3bSMN - Idealized - Normal effort - Level Ref +
4.7dB. Crest factor = 23 dB.
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ICRA: 6pbr
6 persons babble, 1f+1m+2f(-6db)+2m(-6dB), all 3bSMN - Idealized - Raised effort - Level Ref +
10.7dB. Crest factor = 24 dB.
Speech Dialog Crest factor = 24 dB.
Speech Female Crest factor = 20 dB.
Speech Male Crest factor = 25 dB.
Sound File this Crest factor is not known.
Affinity 2.0 Additional Information
2.17 REM PC Shortcuts
Quick Keys
Tab
Shift + Tab
F2
F3
F5
F6
F7
F8
F9
F10
F11
F12
Shift + Mouse scroll or
Shift + Arrow up/down
Mouse Scroll
PgUp/PgDn
Arrow up/down
Control + R
Control + L
Control + B
Next test
Previous test
REM/HIT
Curve smoothing increase/decrease
Offset Y axis
Offset Y axis
Change input level
Right ear
Left ear
Both ears
Start/Stop
Toggle between right and left
Combined or individual curve view
Single or repeated measurement
Manual single frequency
Advanced or simple view
Normal or reversed coordinate system
Jump to current session
Add overlay and jump to current session
Freeze curve
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Affinity 2.0 Additional Information Page 271
2.18 Technical Specifications of the REM440 Software
Medical CE-m ark:
REM440 Software - Technical Specifications
Real Ear Measurement Standards:
The CE-mark indicates that Interacoustics A/S meets the requirements of Annex II of the
Medical Device Directive 93/42/EEC. Approval of the quality system is made by TÜV – identification no. 0123.
IEC 61669, ISO 12124, ANSI S3.46.
Stim uli:
Frequency range:
Warble Tone, Pure Tone, Random noise, Pseudo random noise, Band limited w hite noise,
Chirp, ICRA, Real Speech, any other sound file (automatic calibration available).
100Hz – 10kHz
Frequency accuracy:
Distortion:
Intensity range:
Intensity accuracy:
Measurement Intensity Range:
Frequency Resolution:
Probe m icrophone:
Less than ± 1 %
Less than 2%
40 – 90 dB
Less than ± 1.5 %
Probe microphone 40-145 dB SPL ± 2 dB.
1/3, 1/6, 1/12, 1/24 octave or 1024 point FFT.
Intensity: 40 – 140 dB
Reference microphone:
Intensity Accuracy:
Cross talk
Available tests:
Com patible Software:
Intensity: 40 – 100 dB
Less than ± 1.5 dB
Cross talk in the probe and probe tube w ill alter the obtained results w ith less than 1 dB at all frequencies.
REUR
REIG
REOR
REOG
RECD REUG
REAR Input – Output
REAG
Noah4.0, Noah 3.0, OtoAccess
TM
and XML compatible
Affinity 2.0
Additional Information
3 HIT440
3.1 HIT440 Quick Guide
1) Open Noah and select the patient you want to work with:
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2) Select the Affinity module from the Noah Module menu
3) Select the HIT Icon in the upper right corner of the screen:
IMPORTANT NOTE: The hearing instrument needs to be in FULL ON GAIN MODE/TEST MODE in order to compare the results to the hearing aid manufacturers’ technical data sheets. Each hearing aid manufacturer has a different way of accessing this Test Mode. Please check with the hearing aid manufacturers for instructions on how to program the hearing aid into TEST MODE.
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Additional Information Page 273
4) Position the Hearing Aid in the test box:
BTE: Connect the 2 cc coupler to the BTE adaptor. Place the coupler tube pointing straight forward, and the microphone at the cross.
ITE: Connect the ITE adaptor to the 2 cc coupler and attach the hearing aid using blue putty. Place coupler at the back with hearing aid facing forward with the microphone at the cross. (For multiple microphones, rotate hearing aid to get equal horizontal positioning of the mic inputs).
ITE pick-up coil test: For this particular test only: Position the coupler for maximum sensitivity of the coil.
Open fit/Receiver in the ear: Connect the ITE adaptor to the 2 cc coupler. Remove the tip/dome from the hearing instrument and attach it to the ITE adaptor using blue putty. Place the coupler tube pointing straight forward, and the microphone at the cross.
5) Position the reference microphone next to the hearing aid microphone as shown on the illustrations above.
Affinity 2.0
Additional Information
6) Select the desired test protocol in the List of Protocols
7) Select Test Ear .
8) Select START
9) Please wait for all tests of the selected protocol to be performed:
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Save by clicking “Save” icon
3.2 About HIT440
The HIT440 is a straightforward Hearing Instrument Testing system suited for all types of hearing aids. The system includes ANSI or IEC standards which can be selected from the main screen. This allows for easy technical measures and comparison to the hearing aid manufacturer’s data sheets.
The HIT440 also offers testing of advanced algorithms such as directionality and contains a wide range of test stimuli designed for non-linear hearing aids including the ISTS and ICRAs. These allow you to have an impression of the algorithms functioning together during quick changes in amplitude, frequency and phase.
HIT440 is flexible and permits the creation of an unlimited number of personalized test protocols for different purposes and/or for different professionals working in the same facility. This enables each individual professional to setup the module exactly the way they wish using the specific tests, stimuli and settings they prefer. These personal test protocols can swiftly and easily be chosen at any time accommodating the need for speed in a busy clinic.
Furthermore, the HIT440 allows you to make individual print layouts, keep reports electronically, and compare actual curves to previous sessions. These numerous setup options can be very helpful and time saving in the daily work in the clinic.
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3.3 HIT 440 Tests
Custom selectable tests:
Frequency response
Gain curve
Harmonic distortion
Input/output
Intermodulation distortion
Attack/recovery time
Battery current drain/battery life time
Equivalent input noise
Reference test gain
Directionality
Single frequency
Delay
The IEC standard tests:
OSPL90
Full-on gain
Input/output
Attack/recovery time
Reference test gain
Frequency response
Equivalent input noise
Harmonic distortion
Intermodulation distortion
Battery current drain/battery life time
Coil frequency response
Coil harmonic distortion
Coil full-on gain response
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The ANSI standard tests:
OSPL90
Full-on gain
Reference test gain
Frequency response
Equivalent input noise
Harmonic distortion
Intermodulation distortion
Input/output
Attack/recovery time
Battery current drain/battery life time
Coil frequency response
Coil full-on gain response
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3.4 Launching the HIT 440 Software from Databases
3.4.1 Launching HIT440 from Noah
1) Open Noah and select the patient you want to work with.
2) Select the Affinity module from the Noah Module menu
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The selected suite will now open and automatical ly search for the hardwa re. If i t does no t detect t he har dware a dialog box pops up and asks if you want to run in Simulation mode. To continue with the use of hardware
3) Click the HIT tab in the upper right hand side of the screen to open the HIT440 module (if this is not already active).
3.4.2 Launching HIT440 from OtoAccess™
1. Open OtoAccess™
2. Select the patient you want to work with
3. If the patient is not yet listed:
press the New patient button
fill in at least the mandatory fields, marked with a red asterisk.
save the patient details by pressing Save patient information button.
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4. Double click on Affinity 2 Suite icon in the Select Instrument box
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4) The selected suite will now open and automatically search for the hardware. If it does not detect the hardware a dialog box pops up and asks if you want to run in Simulation mode. To continue with the use of hardware.
Click the HIT tab in the upper right hand side of the screen to open the HIT440 module (if this is not already active)
For further instructions about working with the database, please see the operation manual for OtoAccess™.
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3.5 The HIT440 Screen
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Menu provides access to File, Edit, View, Mode, Setup, and Help.
Print button allows you to will print the test results currently displayed on the screen.
Save & New Session button saves the current session in Noah or
OtoAccess™ and opens a new one.
Save & Exit button saves the current session in Noah or OtoAccess™ and exits the Suite.
Change Ea r button allows you to toggle between right and left ear. Right click on the ear icon to view both ears .
Toggle between single and combined screen button toggles between viewing one or multiple measurements in the same HIT graph.
Toggle between single and continuous measurement button toggles between running a single sweep or having a test signal running continuously until pressing STOP.
Freeze curve allows for taking a snapshot of a HIT curve when testing with broadband signals. In other words the curve freezes at a particular moment while the test continues.
Note that if too many curves are frozen on the screen not all will be saved in Noah due to imposed limitations.
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Select protocol to use from the list allows you to select a test protocol
the current test session (see section 0 for more information about test
protocols).
Temporary Setup button allows for making temporary changes to the selected test protocol. The changes will be valid for the current session only. After making the changes and returning to the main screen, the name of the test protocol will be followed by an asterisk (*).
NOTE : it will only be possible to change protocols that have been created by the user. It is not allowed to modify the protocols that are based on the IEC and ANSI standards. Therefore, Temporary Setup is disabled for ANSI and IEC protocols .
List of historical sessions accesses historical sessions for comparison purposes.
Toggle between Lock and Unlock the Selected Session current or historical session on the screen for comparison to other sessions.
Go to Current Session freezes the
button brings you back to current session.
Report Editor button opens a separate window for adding notes to the
current session (see section 0). Note that after saving the session no
changes can be added to the report once the date has changed.
Single frequency button represents an optional manual test that allows for pre-setting hearing aid gain prior to HIT.
Place the hearing aid in the test box and press the single frequency button. A 1000 Hz tone will then appear allowing you to see the exact input and output of the hearing aid. Press the button again to end the test.
Simple view/Advanced view buttons toggle between an advanced screen view (including the test and fitting prescription information on the right hand side) and a more simple view with a larger graph.
Simple view Advanced view
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Normal and reversed coordinate system buttons enable you to toggle between reversed and normal graph.
This may be helpful for counselling purposes since the reversed curves look more similar to the audiogram and may therefore be easier for the patient to comprehend.
Show curser on graph provides information about each specific measured point in the curve. The curser is “locked” to the curve together with frequency and intensity label placed the curser’s position as illustrated below:
Stimulus selection: With this dropdown list the test stimulus can be chosen. The dropdown is only present for custom made test protocols.
The standards (e.g. ANSI and IEC) have fixed stimuli.
Monitor: If you wish to listen to the amplified stimulus through a monitor.
1. Connect a monitor speaker the monitor output on the hardware.
2. Tick the Monitor check box.
3. Use the slider to turn the sound level up and down.
Note that the sound from the monitor may be very soft (compared to the audiometry monitoring). It is louder for audiometry because the audiometric equipment is producing the signal that is monitored. In
HIT440 the hearing instrument produces the monitored signal meaning
External sound: You can present an external sound through for example a CD player if you have a piece of music/speech you wish to use. This may have a strong effect for counselling purposes. that it cannot be controlled by the equipment. However, if you have an active speaker it will be louder.
1. Connect the CD player to the CD1 input on the hardware.
2. Press START in the software and then tick the External sound check box. The external sound will then play together with the signal.
3. Use the slider to turn the sound level up and down.
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Current Protocol is listed in the lower left hand corner.
The indicates the test is a part of an automatic test flow (Auto Run).
When pressing START all tests with the tick mark will be performed.
If you wish to perform one test only, mark it using the mouse by clicking on it. Then right click at select Run this test .
Upon performing a test the system automatically jumps to the next one in the test flow. indicates that a curve has been measured.
Colour indication shows the colour selected for each curve (in the
Test protocols can be created and adjusted in the HIT440 setup (see
Start/Stop button initiates and ends all tests.
Note that after pressing START the text on the button will change to
STOP .
The Graph shows measured HIT curves. The X axis shows the frequency and the Y axis shows the intensity of the test signal.
Measurement type is printed above the graph together with a right/left indication. In this example the OSPL90 is displayed for the left ear.
Change the input level using the slider on the right hand side.
Scroll graph up/down on the left hand side allows for scrolling the graph up or down ensuring that the curve is always visible in the middle of the screen.
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Measurement details: In this table the curve details can always be viewed. This way the professional always has an overview of what is being measured, for example, information such as Input Level,
Max SPL, Curve Type, Stimulus, and Curve type.
A Curve Comment for each curve can be typed into the comment section on the right hand side.
Select a curve using the curve tag boxes under Curve display options and write a comment in the comment section.
The comment will then appear in the comment section whenever the curve is selected.
Curve Display Options are found in the lower right hand corner.
If you have measured more curves of the same type (e.g.
Frequency response curves), they will be listed by their input level.
Tick the ones that are to be displayed on the graph. Right clicking on this option will allow you to change the curve’s colour or delete the curve.
Affinity 2.0
: The picture indicates whether the hardware is connected.
When opening the Suite the system will automatically search for the hardware. If it does not detect the hardware a dialog box pops up and asks if you want to continue in simulation mode .
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3.6 Hearing Instrument Testing using HIT440
Hearing Instrument Testing (HIT) is performed in order to verify that the hearing aids are technically functioning as they should. It is usually performed after fitting the hearing aid or during a repair appointment.
When performing HIT there are certain things you should keep in mind in order to get the best possible result. Some of these will inevitably also influence the precision of the curve obtained. This section will walk through some important tips and tricks to remember when tasking hearing aids using the HIT440.
The following section will provide you with general knowledge relevant for hearing instrument testing using the HIT440.
Correct placement of a hearing aid in the test box
Positioning the hearing aid correctly in the test chamber is important in order to obtain precise measurements.
3.6.1 Testing Hearing Instruments:
4
2
5
3
6
1) Coupler microphone
2) Ear simulator/711 coupler (optional)
3) 2cc coupler
4) Adaptor for body worn hearing aids
5) Adaptor for BTE hearing aids
6) Adaptor ITE hearing aids
1
1) Connect either the 2cc coupler or the 711 coupler to the coupler microphone and attach the relevant adaptor to the coupler. The parts will click easily together.
Adaptor (BTE) Coupler Microphone
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2) Attach the hearing aid to the adaptor. To attach a BTE use the BTE tubing that is delivered with the system, as shown below.
3) In case of an ITE or open fit hearing aids use blue putty to attach them to the ITE adaptor as shown below:
Note: the microphone should be plugged into the white plug in the Affinity 2.0
test box
3.6.2 Testing bone anchored device using the SKS10 Skull Simulator
With the Interacoustics SKS10 Skull Simulator, it is now possible to perform technical measurements of bone anchored devices. For more information on the setup and test procedures, please refer to the Quick Guide at the end of this document.
The SKS10 is can be used with Affinity Suite version 2.3 or higher.
What is the SKS10?
•
It is a coupler, with a defined mass and an accelerometer, that can measure the force output level of a bone anchored hearing system
•
It emulates the mechanical impedance of the human head
•
It converts the vibrations of the bone anchored device into electrical signals, similar to the way that a standard hearing aid coupler/coupler microphone converts sound waves into electrical signals.
•
It can be connected either to the internal test-box of the Affinity 2.0
or to an external test-box (TBS25) connected to the Affinity 2.0
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How does it work?
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Required items:
•
•
The Affinity hardware
•
The Interacoustics SKS10 Skull Simulator and its power supply
•
The HIT440 Software license
•
The SKS10 Skull Simulator license
•
A bone anchored device
Optional: the TBS25 passive HIT box, connected to the Affinity
3.6.3 Installing the Skull Simulator License in the HIT440 Software:
3.6.3.1 How to receive a new HIT license
1- After purchasing the SKS10 and the license, please send Interacoustics
) the serial number. You can find out by going to the Affinity software and going to Menu/Help/About License “Copy s/n”
2- Paste the serial number in the body of an email and send it to Interacoustics
3- Interacoustics will then email a new HIT license
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3.6.3.2 Activating the new HIT license
1- Go to HIT module/Menu/Help/About
2- Click on License
3- Paste the new license number under HIT (New license)
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The Skull protocol might be hidden in the software. If this is the case; it is necessary to activate it:
1- Go to HIT/Menu/Setup/HIT440 setup
2- Choose “Skull Simulator” under “Selected Protocols”
Under “General Settings”, ensure that “Skull Simulator” is chosen under “Coupler”
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3.6.3.3 Using the Skull Simulator protocol
A default protocol for the Skull Simulator is available from the protocol drop down menu. Since a standard
ANSI or IEC protocol does NOT exist for bone anchored devices, the Skull Simulator default protocol was created as a starting point and to give inspiration to create your own protocol, according to user needs.
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3.6.3.4 Setup of SKS10 in the Affinity test chamber
Since the SKS10 contains an accelerometer, it needs to be powered by an external power source. Please ensure that the SKS10 is connected to the power supply and the power supply is connected to a power source.
1- Connect the skull simulator to the power supply and ensure power supply is connected to a power source
2- Connect the white plug into the white socket inside the Affinity Test Chamber
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3- Snap on the bone anchored device onto the abutment of the skull simulator.
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NOTE: For more information on how to setup the Affinity and test bone anchored devices, please see the
Quick Guide for testing bone anchored devices with the SKS10 , this can be accessed via the link mentioned at the end of this document.
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3.6.4 Running Pre-programmed Test Protocols
1) Place the hearing aid in the test box (as described in section 0)
2) Select the appropriate ear
3) Select a test protocol
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Select START to run the test automatically
The Auto Run function will ensures that all test in the protocol are performed automatically. The tests included automatic test flow will be marked with a .
3.6.5 Automatic Testing (Auto Run)
Auto Run ensures that the tests in the test protocol are run as an automatic test flow meaning that all tests are performed when pressing START. Tests included in the Auto Run is marked with a in the test screen.
Auto Run check marks
ONLY the tests marked with a will be performed when pressing START. To run the remaining tests these need to be activated manually. This is done by clicking on the relevant test, then right clicking and select Run this test .
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Auto Run can be setup in the HIT440 setup ( Menu/setup/HIT440 setup ).
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Next to each test you will find a Play symbol (Auto Run) or a Stop symbol (Manual Run) .
Click on the Play/Stop symbols for each test to toggle between Auto and Manual Run.
See more information about protocol setup in section 0.
3.6.6 Preconditioning and Sweep Delay
3.6.6.1 Preconditioning
Preconditioning is relevant when using broadband signals such as for example ISTS/ICRA. It consists of a wideband signal followed by a pure tone appearing just before the selected stimulus is presented.
The precondition function allows you to set a certain time before the curve is shown on screen. This will allow the hearing aid algorithms to have time to switch on and stabilise in a setting as caused by a non-linear stimulus. This has two effects – first of all you will avoid the hearing aid being in the process of changing characteristics during the test, and secondly, the hearing aid will in this case be brought into the mode corresponding to the stimulus.
3.6.6.2 Sweep Delay
The sweep delay is the time before the next sweep will start when running a continuous measurement using
Pure Tone or Warble Tone. Modern hearing aids often have advanced algorithms that need a certain reaction time. It is therefore helpful to be able to set individual delays.
3.6.7 Smoothing a Curve
Smoothing is a technique where small details in the curve appear to be ironed out. As these details sometimes have a noisy character, smoothing may be preferred. The individual tests can be designed to
have more or less smoothing applied in the HIT440 setup (described for each test in section 0).
Smoothing can also be applied after measuring in two ways:
Shift + up/down arrow keys on the PC keyboard
Shift + the scrolling wheel on the mouse
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Examples:
Smoothing index 0
Smoothing index 5
Smoothing index 10
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Note: Numerically reported MAX OSPL90 Level is determined from a non-smoothed curve, and as such not affected by smoothing level, even though the smoothed waveform may appear to have a reduced peak around the MAX SPL area.
3.6.8 Show Cursor on the Graph
When comparing the graph in the fitting software/specification sheet to the graph in the HIT440 the Show cursor on graph may be useful. Upon selecting the function the cursor will “glue” to the highlighted curve showing the exact measured value at each frequency.
Note: As the cursor tracks the displayed curve, any smoothing applied to the curve will influence the reading.
This may have the effect that a smoothed curve will report one max OSPL90 level with the cursor and a different max OSPL90 level in the numerical data section. Unsmoothing will make the two readings identical.
3.6.8.1 Managing Multiple Curves
If measuring many curves during the same test session there are several ways to provide a more simple view (or a comparison view) showing only the preferred curves in the same graph.
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3.6.8.2 Curve Display Options
In the curve display options box all curves are listed by input level and color.
If many of the same curve type (e.g. Frequency Responses) have been measured tick only the ones that you wish to display on the graph.
Un-ticked curves will be hidden ensuring a less confusing screen view.
3.6.8.3 Combined Screen View
If a combined screen is setup you may want to compare to other curves obtained. Press the corresponding button to toggle between single and combined screen:
In the combined screen setup you can decide exactly which curves are to be compared so that for example
for how to do a combined screen setup).
3.6.8.4 Changing the Curve Color
If having many curves on screen you can change their colors even after they are measured. Right click on the preferred curve and choose Change curve color . The system will then allow for choosing a new color.
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3.6.9 Comparing Curves
The HIT440 also allows for comparing either two historical curves (e.g. two OSPL90 curves) or comparing a historical curve to a currently recorded curve. This is done following the procedure described below:
1) Find the first curve in the Session list . Historical HIT measures are listed by date and time of saving.
2) Press Toggle between lock and unlock the selected session
3) Find the second curve in the Session list. This can be either a curve of the current session or a historical curve.
The two curves are now shown in an overlap view as illustrated below:
Note: To avoid comparing apples to oranges, only curves of the same type can be compared – hence it is not possible to compare results from an ANSI based test protocol with curves acquired with an IEC or
Custom based test protocol. Ideally the same test protocol should be used for this type of comparison.
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3.6.10 Comparing to the manufacturers specification sheets
When comparing a measurement to the hearing aid manufacturer’s specification sheet it is important keep in mind that the same hearing aid settings that were used in the specification measures should also be used for the HIT440 measures!
If the parameters are not accordance with each other the comparison will not be valid.
Most hearing aid manufacturers use known international standards, such as the ANSI or IEC for their specification sheets. The same standard can usually be selected in the HIT440 software.
The hearing aid can typically be programmed with a “technical measurements” setting found in the fitting software (please refer to the manuals of the specific hearing aid brands for details). These ensure correct settings for the ANSI/IEC comparisons.
If you do not use international standards, please be sure to check the following:
Ensure that the stimulus used in HIT440 is the specification sheets
Ensure that the input level used in the HIT440 is the same as in the specification sheets
Ensure that the hearing aid is programmed with the exact same gain settings as used in the specification sheets.
3.6.10.1 Telecoil Testing
For all telecoil measures please ensure that the hearing aid telecoil is activated.
The Affinity 2.0
test boxes include a magnetic field which enables testing of hearing aid telecoils. This is relevant for frequency responses, gain curve, harmonic distortion, battery current drain, OSPL90, and full-on gain.
Procedure:
1)
Place the hearing aid in the test box as described in section 0.
2) Switch to the telecoil program
3)
Perform the telecoil tests as described in section 3.7.1.
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As an add-on the Affinity 2 test boxes also includes a TMFS coil shown below.
TMFS is short for Telephone Magnetic Field Simulator. It is a transducer that produces a magnetic field similar to the signal coming out of traditional telephones. In other words the TMFS coil attempts to simulate a telecoil for the purpose of calibrating hearing aids with inductive coils according to ANSI S3.22:2003
Place the hearing aid on top of the TMFS coil as shown on the illustration below.
It is important to note that telecoils may still be tested without the TMFS coil as the Affinity 2.0
test box has a built in magnetic field which is different from the field created by the TMFS coil. However this will not be in accordance with the ANSI standard.
The magnetic field is generated at the circle indicated on the TMFS coil. The hearing aid telecoil should be located as close as possible.
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