otometrics Madsen Midimate 602 User manual

602 & 622
Diagnostic Audiometers
Quick Guide
Doc no. 7-50-0070/01
Part no. 7-50-00700
0459

FM template version: 01-02-2010
Copyright notice
No part of this Manual or program may be reproduced, stored in a retrieval system, or transmitted, in any form
or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written con-
sent of GN Otometrics A/S.
Copyright© 2011, GN Otometrics A/S
Printed in Denmark by GN Otometrics A/S, Denmark
All information, illustrations, and specifications in this manual are based on the latest product information
available at the time of publication. GN Otometrics A/S reserves the right to make changes at any time with-
out notice.
Version release date
15. September 2011
Technical support
Please contact your supplier.
GN Otometrics A/S
9 Hoerskaetten
DK-2630 Taastrup Denmark
T: [phone], F: [phone]
www.otometrics.com

MIDIMATE 602 & 622 Diagnostic Audiometers
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Contents
1 Introduction ..................................................................................................................... 5
1.1 Standards and safety precautions.......................................................................... 5
1.2 About this manual ................................................................................................... 6
1.2.1 Not covered in this manual ............................................................................. 6
1.2.2 Abbreviations and terms ................................................................................. 6
2 Installing the MIDIMATE 602/622............................................................................... 7
2.1 Rear panel ................................................................................................................. 7
2.1.1 Connecting transducers and other devices ................................................... 7
2.1.2 Connecting the electric power supply ........................................................... 8
3 Setting Up Test Parameters............................................................................................ 9
3.1 Preprogrammed user tests...................................................................................... 9
3.2 Manual setup by menu............................................................................................ 9
4 Pure Tone Testing ......................................................................................................... 11
4.1 Air Conduction thresholds ................................................................................... 11
4.1.1 Preparing for the test...................................................................................... 11
4.1.2 Testing the patient .......................................................................................... 11
4.1.3 Testing patients with large threshold differences...................................... 12
4.1.4 Correcting a threshold invalidated by contralateral bone conduction ... 13
4.1.5 Locking the masking level to the hearing level.......................................... 13
4.1.6 Testing above 110 dB HL............................................................................... 13
4.1.7 Setting a minimum tone presentation time................................................. 13
4.2 Bone Conduction thresholds ................................................................................ 14
4.2.1 Masking with TDH39 headphones .............................................................. 14
4.2.2 When to use a masking insert phone........................................................... 14
4.3 Free-Field thresholds ............................................................................................. 15
5 Testing with Speech ...................................................................................................... 16
5.1 Live speech testing................................................................................................. 16
5.1.1 Setting up the test ........................................................................................... 16
5.1.2 Testing the speech reception threshold ....................................................... 16
5.1.3 Testing speech discrimination ...................................................................... 17
5.2 Testing with recorded speech .............................................................................. 17
5.3 Testing with Free-Field speech ............................................................................ 18
6 Special Tests ................................................................................................................... 20
6.1 The SISI test............................................................................................................. 20
6.2 Fowler’s test ............................................................................................................ 21
6.3 Stenger’s test ........................................................................................................... 22
6.4 The Rainville test.................................................................................................... 22
7 Programming a User Test ............................................................................................ 24
7.1 Accessing user test programming mode ............................................................ 24
7.2 Programming a user test....................................................................................... 24
8 Data Interface.................................................................................................................25
8.1 Entering patient ID ................................................................................................ 25
8.2 Printing audiograms (MIDIMATE 622 only)..................................................... 25
8.2.1 Storing test results .......................................................................................... 25
8.2.2 Printing an audiogram................................................................................... 25
8.2.3 Viewing stored test results ............................................................................ 26
8.2.4 Printing separate Air and Bone Conduction audiograms......................... 26
8.3 Setting up printout................................................................................................. 26

MIDIMATE 602 & 622 Diagnostic Audiometers
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MIDIMATE 602 & 622 Diagnostic Audiometers
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1 Introduction
1.1 Standards and safety precautions
Standards. The MIDIMATE 602/622 complies with the following standards for
audiometers: EN 60645–1, –2; ANSI S3.6.
The MIDIMATE 602/622 and this manual are CE-marked according to the
Medical Devices Directive 93/42/EEC.
The MIDIMATE 602/622 is marked with this symbol to indicate compliance
with Type B requirements of EN 60601–1.
Safety. This operation manual contains information and warnings, which must be
followed to ensure the safe performance of the MIDIMATE 602/622. Local govern-
ment rules and regulations, if applicable, should also be followed at all times. Special
note should be made of the following:
The MIDIMATE 602/622 is marked with this symbol when it is important that
the user refers to associated warnings given in this manual.
Any personal computer connected to the MIDIMATE 602/622 must comply
with the requirements of IEC 950, “Safety of information technology equip-
ment, including electrical business equipment”.
Service and repair. Service and repair of electromedical equipment should be carried
out only by the equipment manufacturer or by authorized representatives. The
manufacturer reserves the right to disclaim all responsibility for the operating safety,
reliability and performance of equipment serviced or repaired by other parties.
Cleaning and disposal. Periodically clean the LCD screen. Use an anti-static non-
solvent solution on a lint-free cloth. Use a soft brush to remove dust. Use a small
amount of mild detergent on a damp cloth to clean the cabinet and front.
Earphones, the eartip of the masking insert phone and the bone vibrator should be
cleaned regularly with a damp cloth.
Do not attempt to clean and re-use the disposable yellow foam insert tips for the op-
tional E–A–RTONE 3A Masking Insert Phone. No special disposal requirements ap-
ply to these insert tips.
When the MIDIMATE 602/622 is taken out of use, it should be disposed of in com-
pliance with local regulations for disposal of electrical equipment.
Caution! Do not use chemical cleaning agents containing ammonia or alcohol as they
will damage the cabinet and display.

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1.2 About this manual
This manual is intended for audiologists, audiological assistants and health care staff
in related professions performing audiological tests on patients.
1.2.1 Not covered in this manual
Some MIDIMATE 602/622 functions are not covered in this manual. This includes
changing a fuse, changing the supply voltage, some power-on options, calibration,
some print setup, printout trouble-shooting, on-line operation to a personal com-
puter (except patient ID), and tables of setup structures and procedures, as well as
test setups and print options.
1.2.2 Abbreviations and terms
Display texts and front panel controls are shown in the Courier font.
The following abbreviations are used in the MIDIMATE 602/622 display:
ABLB = Alternate Binaural Loudness Balance
Bin. S+M = Binaural Stimulus plus Masking
C= Continuous
Ext = External (Tape 1/Tape 2)
F.F = Free-Field
HLL =HearingLevelLock
L =Left
NBN = Narrow Band Noise
P =Pulsing
PTS = Patient Signal
R =Right
SISI (A) = Short Increment Sensitivity Index (Air)
SN = Speech Noise
W = Warble
WN = White Noise
The five numbered keys below the display are referred to as Softkey 1 to 5because,
unlike the other keys, the software determines their functions. The current function of
each Softkey is shown above it in the display (with a few exceptions, such as when
you press Softkey 3 in test mode the Options Menu is displayed. In cases where
the displayed Softkey function shows a choice, the current selection is underlined, as
in On/Off.

MIDIMATE 602 & 622 Diagnostic Audiometers
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2 Installing the MIDIMATE 602/622
2.1 Rear panel
2.1.1 Connecting transducers and other devices
Before you switch on the electric power, connect the following, as required, to the
Rear Panel (or elsewhere, where described):
• Data Interface (MIDIMATE 622 only). 25-pin RS-232C serial connection for op-
tional operation together with one of the following:
1. An external printer via cable part no. 8–71–420;
2. The ZODIAC 901 via cable part no. 8–71–340;
Note!
For communication with ZODIAC 901, the Baud rate must be set to 9600.
3. A personal computer, via cable part no. 8–71–340. Must comply with IEC
950 requirements, “Safety of information technology equipment, including
electrical business equipment”. See “Data Interface Operation Manual” (7–
26–121).
• Pt-Sign. For the Patient Response Handswitch.
• Phone L (Left = blue), R(Right = red).Calibrated for use with the TDH 39 head-
phones supplied as standard with the MIDIMATE 602/622 fitted on an ME 70
noise-excluding Headset or on a TC 89E Headband.
• Bone. For the B–71 Bone Conductor (§4.2).
Warning!
Do not remove or tamper with the bone conductor cable while it is
connected to the MIDIMATE 602/622. Either disconnect the cable from the
Rear Panel or switch off and disconnect the electric power supply first.
• Insert. For the optional Insert Phone for masking (§4.2.2).
• FF, L and R. (Free Field, Left and Right) For optional free-field loudspeakers via
external amplifiers. Max 3 V RMS from 500 Ω.
• Monitor. For optional monitor headset with boom microphone 8–75–340 or op-
tional monitor adaptor 8–71–140 with monitor loudspeaker (such as 8–75–330)
and talkover/live voice microphone (such as 8–72–240).
• TB-Mic. For optional patient talkback microphone.
• Tape 1, Tape 2. For pre-recorded speech from an optional stereo CD player or
tape-recorder. Sensitivity 0.1 V to 3.0 V RMS into 47 kΩ.

MIDIMATE 602 & 622 Diagnostic Audiometers
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2.1.2 Connecting the electric power supply
Before switching on the MIDIMATE 602/622, read the following:
Warning!
Before you connect the power cable, make sure that the voltage from the
electrical outlet matches the voltage shown on the Voltage Selector located beside the
Power switch.
If necessary, use a small screwdriver to unscrew the two screws at the back of the top
panel. Tilt the top panel forwards and remove it. Set the correct voltage and remount
the top panel.
Warning!
Operating at the wrong voltage may blow the fuses.
Warning!
Do not change the voltage selection while the power is connected.
Caution!
Always use an electrical power supply with protective earth, which complies with IEC
requirements, such as (a) the power cable supplied, (b) an electrical power supply
tested to IEC requirements, (c) a power cable fitted with a 3-pin plug, (d) an extension
cable with earth connection, and (e) an extension cable which does not increase the
resistance of the earth connection.
Caution!
As this may generate a click, do not switch on the MIDIMATE 602 while the
headphones are being worn.
Caution!
Do not leave the optional dust cover on the MIDIMATE 602 with the power switched
on.
To switch on press the on/off switch on the right side of the cabinet. The green
Power LED on the front panel lights when the power is on.

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3 Setting Up Test Parameters
Use the MIDIMATE 602/622 to test patients with one of five pre-programmed User
Tests (§3.1), or with a manual setup by menu (§3.2). MIDIMATE 622 may be set up
to store and display for viewing and/or print out thresholds as described in §8.2.
3.1 Preprogrammed user tests
MIDIMATE 602/622 is delivered with Tests 1 to 3pre-programmed with typical
setups for Tone/Air (§4.1), Tone/Bone (§4.2) and Speech testing with recorded
speech (§5.2). To change the setup of these tests and pre-program Tests 4 and 5see
Chapter 7.
To select one of the other User Tests, do as follows:
1. Press Menu until Select User Test is displayed.
2. Press the Softkey corresponding to the required User Test.
3. If required, hold down the selected Softkey to interrupt the automatic setup se-
quence. When the sequence is completed the MIDIMATE 602/622 is ready for
testing.
3.2 Manual setup by menu
To set up the test parameters manually, do as follows. To backstep in this procedure,
press Menu instead of a Softkey.
1. Press Menu to display the Select Function screen. The upper line shows the
current function and the lower line shows the options you can select by pressing
the Softkeys.
2. Press Softkey 1, 2or 3to select the Function (Tone, Speech or Special) with
its corresponding Output screen.
3. Press Softkey 1, 2or 3to select the Output (Air, Bone or F.F.) and display the
Stimulus Side screen.
4. Press Softkey 1,2 or 3 to select the Stimulus Side (Left, Right or L+R) and
display the corresponding Masking screen, or Input screen in the case of
Speech.
5. If you selected Speech in step 0, press Softkey 1 or 2to select the required Input
(Tape (CD) or Micr.) with its corresponding Masking screen.
6. Press Softkey 1,2,3 or 4to select the type of Masking (No Mask, Air, Ipsi or
Bin. S+M) and to see a list of the selections made (including a reference number
for the selected setup).
7. After a few moments the default settings for the selected test are shown. If re-
quired, change any of these settings by toggling the corresponding Softkey.

MIDIMATE 602 & 622 Diagnostic Audiometers
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8. To set the Tone Switch so that it gives a minimum of 1.5 s stimulus when it is
pressed, press Softkey 3 to display the Options Menu and toggle Softkey 1 un-
til 1.5s On is displayed. Wait 5 sec or press Menu to return to test mode.
9. To change the level resolution, press Softkey 3 to display the Options Menu
and toggle Softkey 1 until 1 dB or 5 dB is displayed. Wait 5 sec or press Menu
to return to test mode.

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4 Pure Tone Testing
4.1 Air Conduction thresholds
4.1.1 Preparing for the test
Before you test the Air Conduction thresholds of a patient, make the following
preparations:
1. Connect the patient response handswitch, the headphones, the optional monitor
headset (or the optional monitor adaptor with talkover microphone and monitor
loudspeaker), and the optional patient talkback microphone.
2. Switch on the electric power supply.
3. Select User Test 1 or change the setup as described in Chapter 0, and make sure
that the setup begins with Tone, Air.
4. If you use an optional monitor headset or loudspeaker, it will normally give an
audible response each time the patient activates the patient response handswitch.
To disable or re-enable this function, press Softkey 3 in test mode to display the
Options Menu, and then toggle Softkey 5. The display shows PTS-Off when
you can disable the function by pressing Softkey 5, and vice versa. The display
returns automatically to the current test values after a few moments.
5. Check the monitored level of audible response from the patient response hand-
switch if it is enabled, and, if necessary, use a screwdriver to adjust the Pt. Vol.
level on the rear panel until this level is comfortable.
4.1.2 Testing the patient
To test the patient, do as follows:
1. Place the patient, facing away from the MIDIMATE 602/622, preferably in a
sound-cabin.
2. Instruct the patient in how to use the patient response handswitch. When the pa-
tient presses the handswitch, the Response light on the front panel lights, and
there is a signal in the optional monitor headset or monitor loudspeaker.
3. If required, instruct the patient in how to use the optional talkback microphone.
4. To check the monitored level of the patient’s talkback press the Talkback key in
the right-hand Level section of the front panel, and change it, if required, by
turning any of the rotary wheels while you hold down the key. The Response in-
dicator shows the percentage used.
5. To check the monitored level of the stimulus press the Monitor key in the right-
hand Level section of the front panel, and, if required, change it by turning any of
the rotary wheels while you hold down the key. The Stimulus indicator shows
the percentage used.

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6. Fit the headphones on the patient, with the red phone on the right ear.
7. If required, test the level of the operator’s monitor or talkover microphone on the
patient. If needed, adjust by pressing and holding down the Microphone key in
the left-hand Level section of the front panel, or the Talk Over key and turning
any of the rotary wheels. The Stimulus indicator shows the percentage used.
8. Toggle Shift L/R to select the ear with the better hearing to be tested first. The ear
selected for testing is shown on the display above Softkey 3.
9. Turn the Frequency wheel to set the stimulus frequency shown on the display
above Softkey 1. Testing normally starts at 1000 Hz.
10. Toggle Softkey 2 to Pif pulsed tone is required.
11. To present the stimulus tone to the patient’s test ear, press the Tone Switch,
which is the large key below the Hearing Level wheel. The Stimulus indicator
lights to confirm that the tone is presented and displays the intensity as long as
the Tone Switch is held down.
12. Turn the Hearing Level wheel to change the stimulus intensity until the patient’s
threshold is found for the current frequency (displayed above Softkey 1), and
read its value from the display above Softkey 3.
13. If Store is set up, press Softkey 3 twice to store this value (MIDIMATE 622
only).
14. Repeat the test at the next frequency. Testing is usually done at increasing fre-
quencies until the highest frequency is reached, and then to test at the frequencies
below 1000 Hz in descending order.
15. Repeat the test for the poorer ear.
4.1.3 Testing patients with large threshold differences
If the difference between the thresholds in the two ears is greater than 40 to 60 dB, do
as follows:
1. Press Menu to display the Select Function menu.
2. Press Softkey 2 to select Air, which presents Narrow Band Noise (masking) to
the better (contralateral) ear.
3. Use Softkey 4 to toggle masking On.
4. Turn the Masking Level wheel to set the masking level shown on the display
above Softkey 5.
5. Cooperate with the patient to determine the threshold for Narrow Band Noise for
the contralateral ear.
6. Set Masking to a level 15 dB above this threshold.
7. Continue to apply masking to the better ear. Present a tone to the poorer ear at
the hearing level that was previously determined to be the tone threshold with-
out masking.

MIDIMATE 602 & 622 Diagnostic Audiometers
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If the patient can still hear the tone, this is the valid threshold. If the patient cannot
hear the tone, this is because the threshold determined without masking has been
invalidated by contralateral bone conduction to the better ear. How to obtain the
valid threshold is described in §4.1.4.
4.1.4 Correcting a threshold invalidated by contralateral bone conduction
In cases where the tone threshold determined for the poorer ear has been invalidated
by contralateral bone conduction, do as follows:
1. Press Softkey 3 to display the Options Menu.
2. Toggle Softkey 2, 1 dB/5 dB, to change the level resolution for both hearing
level and masking to 5 dB.
3. Increase the hearing level of the tone in 5 dB steps and present the tone. Do so
until the patient can hear it.
4. Increase the masking level by 5 dB and repeat step 2.
5. Repeat step 3 until an increase in masking level does not change the tone thresh-
old.
The tone threshold determined under these conditions is the correct one.
4.1.5 Locking the masking level to the hearing level
You can lock the masking level to the hearing level so that any change in the hearing
level results in a corresponding change in the masking level. Do as follows:
1. In test mode press Softkey 3 to display the Options Menu.
2. Toggle Softkey 4 to activate hearing level lock. If the display shows HLL-On, the
hearing level lock will be activated when you press Softkey 4.
3. To change the interval between the Masking and Hearing levels, turn the Mask-
ing wheel.
4.1.6 Testing above 110 dB HL
To override the MIDIMATE 602/622 110 dB (approx.) hearing level limit, which is
built in for safety purposes, toggle the Ext. Range HL key so that the Ext. Range HL
lamp lights up. You can then test patients at maximum hearing levels up to 25 dB
greater, depending on the transducer in use.
4.1.7 Setting a minimum tone presentation time
Press Softkey 3 to display the Options Menu, and then Softkey 1, 1.5s On/Off,
to enable or disable an automatic timer which sustains the effect of pressing the Tone
Switch for a minimum of 1.5 s.

MIDIMATE 602 & 622 Diagnostic Audiometers
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4.2 Bone Conduction thresholds
Masking is always necessary when Bone Conduction thresholds are tested because of
the reduced level of contralateral attenuation.
4.2.1 Masking with TDH39 headphones
The procedure for testing the patient’s Bone Conduction thresholds differs from that
for Air Conduction as follows:
1. Connect the B–71 Bone Conductor into the Bone socket on the rear panel.
2. Select User Test2 (as described in Chapter 0) to see the set-up for Bone Con-
duction, unless the default settings have been changed.
3. Make sure that there are no interfering ambient sounds, especially at low fre-
quencies, — if necessary place the patient in a sound cabin.
4. Fit the headphones so that the red (right) phone is applied to the poorer ear for
masking, and the other phone is applied to the patient’s temple region, leaving
the ear to be tested uncovered.
5. Use L/R Shift to select the masking output required
6. Use Softkey 4 to toggle Air Off.
7. Use a tone hearing level about 10 to 20 dB above threshold, and check with the
patient to find the most sensitive part of the mastoid to place the Bone Conduc-
tor. Make sure that there is no contact between the headband, which secures the
Bone Conductor, and the headset or headband supporting the TDH39 head-
phones which could conduct vibrations from one to the other. Leave it in this po-
sition until the test is finished.
8. Determine the threshold without masking.
9. Use Softkey 4 to toggle Air On.
10. Test the threshold again with masking.
11. If the threshold has changed, determine the true threshold by testing in the same
way as in §4.1.4.
12. Switch the Bone Conductor and headphone to the opposite ears. Test the poorer
ear with masking applied to the better ear.
13. If the bone conduction thresholds for the two ears prove to be very different, use
a masking insert phone (optional accessory) instead of the TDH39 headphones.
4.2.2 When to use a masking insert phone
The optional masking insert phone (8–75–250) has a much lower level of bone con-
duction caused by vibration than the TDH39 headphones. Use the masking insert
phone instead of the TDH39 headphones for masking when you test the Bone Con-
duction threshold of patients with much more hearing loss in one ear than in the

MIDIMATE 602 & 622 Diagnostic Audiometers
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other. This is to avoid “false” contralateral masking caused by the high masking level
required in the weaker ear.
The test procedure is similar to that described in §4.2.1.
4.3 Free-Field thresholds
Free-field pure-tone testing, with loudspeakers instead of headphones, is used pri-
marily when the patient for instance is a child who dislikes wearing headphones.
However, the measured thresholds will be influenced by:
• The distance from the loudspeakers to the patient;
• The acoustic absorption of the walls of the test room;
• Ambient noise.
Loudspeakers (such as 8–02–450) and a two-channel power amplifier such as PA 210 (8–02–
240) for free-field testing are optional accessories.
To set up a free-field tone test, do as follows:
1. Connect the amplifier’s left and right inputs to FF, Land Ron the rear panel.
2. Connect the loudspeakers to the amplifier’s outputs.
3. Press Menu to display the Select Function menu.
4. From the Select Function menu press Softkey 1 to select the (Tone) Out-
put ? menu.
5. From the (Tone)Output ? menu press Softkey 3 to select F.F.
6. From the (Tone,F.F) Side ? menu press Softkey 1 to select Left.
7. From the (Tone,F.F,Left) Masking ? menu press Softkey 3 to select FF.
To minimize the influence of standing waves on the measured threshold, the test
tone is frequency modulated to a depth of ±5% by a warble tone. If required, you can
disable this by toggling Softkey 2 so that C/P/W is displayed instead of C/P/W.
To use the narrow band noise provided for masking as an alternative test source in-
stead of tone, do as above but with the following differences:
8. Press Softkey 2 to select Right instead of Left in step 5.
9. Toggle Softkey 4 to display F.F On/Off.
10. Turn the Hearing Level wheel counterclockwise to reduce the tone to minimum.
11. Use the Masking Level wheel to see the threshold (displayed above Softkey 5)
for each center frequency.

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5 Testing with Speech
5.1 Live speech testing
5.1.1 Setting up the test
To set up a test of a patient’s live voice threshold, do as follows:
1. Connect either the monitor headset with boom microphone or a monitor loud-
speaker and talkover/live voice microphone via the monitor adaptor to Monitor
on the rear panel. If you use the monitor loudspeaker and talkover/live voice mi-
crophone, you should speak the words into the microphone with a fixed distance
of about 20 cm between your mouth and the microphone.
2. Place the patient in a sound cabin to make sure that the live voice is heard only
via the MIDIMATE 602/622. If no sound cabin is available fit the patient with an
ME 70 noise-excluding headset to prevent threshold levels which are nearly nor-
mal from being influenced by directly transmitted live voice.
3. Press Menu to display the Select Function menu.
4. Press Softkey 2 to select Speech and display the Output menu.
5. Press Softkey 1 to select Air and display the Stimulus menu.
6. Press Softkey 1 to select Left and display the Input menu.
7. Press Softkey 2 to select Micr. and display the Masking Output/Input
menu.
8. Press Softkey 1 to select No Mask unless there is a risk of a response from the ear
not being tested. This may be the case either because of widely differing thresh-
olds, or because the test is to be made at a level well above threshold. For mask-
ing, press Softkey 2 to use white noise (WN), or Softkey 3 to use speech noise
(SN), which is white noise filtered so that speech frequencies predominate.
9. Press and hold the Microphone pushkey on the Level panel and turn any of the
three rotary wheels while you read aloud from a word list. Use a word list, where
the words have been expressly prepared for threshold measurements in order to
obtain a peak deflection of 0 dB on the Stimulus VU indicator. (0 dB corresponds
to normal threshold.) Make sure that the level, the pace and the distance from the
microphone of the live voice used for setting up is the same as for the actual test.
5.1.2 Testing the speech reception threshold
The patient’s speech reception threshold is defined as the sound pressure level for
which the patient can repeat correctly 50% of the words in a spoken list. Each of the
words used for this test is of two syllables stressed equally (spondees). To test the
patient, do as follows:
1. Instruct the patient carefully in how to repeat each word he hears.

MIDIMATE 602 & 622 Diagnostic Audiometers
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2. If possible, select the better ear to test first by toggling L/R Shift.
3. Read from the list while you turn the Hearing Level wheel to find the lowest
level at which the patient can still repeat each word correctly.
4. Turn the Hearing Level wheel counterclockwise to reduce the L.Micr level
shown above Softkey 3 by 5 dB.
5. Continue the test to determine the percentage of words, which the patient repeats
correctly at this level.
6. Repeat steps 3 and 4 until the percentage of at least 20 words, which the patient
repeats correctly, falls below 50%. Make a note of both the level and the corre-
sponding percentage in each case. Normally the first few words are sufficient to
establish the patient’s score, and the remaining words serve to confirm it.
7. Determine the patient’s hearing loss, by interpolation if necessary, from the level
corresponding to a 50% score.
8. Toggle L/R Shift and repeat steps 2 to 6 for the other ear.
If necessary, repeat the procedure with progressively increasing levels.
5.1.3 Testing speech discrimination
To test a patient’s speech discrimination, do as follows:
1. Prepare for the test as described in §5.1.1. Each of the words used for discrimina-
tion testing must be phonetically balanced. Because of the relatively high levels
used in discrimination testing, masking is usually recommended to prevent an
unwanted response from the ear not being tested.
2. Record the score of correctly repeated words for a test conducted at a level of
40 dB above the patient’s speech threshold. At this level a patient with normal
hearing would score 100%. Patients with hearing loss resulting in reduced dis-
crimination may score as little as 40% to 50%, and for certain kinds of hearing
loss their score may be reduced at increased hearing levels.
3. Repeat the test at other levels to determine if the score varies with level.
4. Toggle L/R Shift and repeat the test on the other ear.
5.2 Testing with recorded speech
The setup for testing the patient using pre-recorded word lists is similar to the pro-
cedure described in §5.1.1, with the following differences:
1. Connect the output of a tape recorder or CD player to Tape 1, and in the case of a
two-channel or stereo signal to Tape 2 as well.
2. Placing the patient in a sound cabin is not necessary, as there is no direct path for
the sound.

MIDIMATE 602 & 622 Diagnostic Audiometers
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3. If you are using recorded speech for testing, a high-quality talk back microphone,
amplifier and headset are required. If they are not used, there may be discrimi-
nation loss because it will be difficult to hear the patient repeat the words. The
microphone should be uni-directional and should be placed close to the patient.
4. The recorded speech material used for the test must have a stated relation with a
recorded calibration signal.
5. Select User Test 3 (§3.1) instead of step 0, unless the default setting has been
changed, or press Softkey 1, Tape (CD), instead of Softkey 2 in step 0.
6. Instead of doing as in step 0, start the tape recorder or CD player. Keep pressing
the Tape 1 pushkey on the Level panel and turn any of the three rotary wheels in
order to obtain a peak deflection of 0 dB on the Stimulus VU indicator.
The procedures for threshold and discrimination testing with recorded speech are
similar to those described in §5.1.2 and §5.1.3.
5.3 Testing with Free-Field speech
For Free-field speech testing use loudspeakers (such as 8–02–450) and a two-channel
power amplifier such as PA 210 (8–02–240) instead of headphones to present the
speech to the patient. The measured thresholds will be influenced by:
• The distance from the loudspeakers to the patient;
• The acoustic absorption of the walls of the test room;
• Ambient noise.
Free-field speech testing is especially useful for fitting hearing aids, particularly those de-
signed to compensate for perceptive-type hearing loss and discrimination loss. With masking
applied, it is also useful for testing children who dislike wearing headphones.
To set up a free-field tone test, do as follows:
1. Press Menu to select the Select Function display.
2. Press Softkey 2 to select Speech.
3. Press Softkey 3 to select F.F.
4. Press Softkey 1 to select Left.
5. Press Softkey 1 to select Tape (CD).
6. Press Softkey 1 to select No Mask. If masking is required, you can select WN
(Softkey 2), SN (Softkey 3) or Ext (Softkey 4).
7. Adjust the level of the stimulus as described in step 0 in §5.2.

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8. If you have selected Ext masking, set the masking reference level. To do so turn
any of the rotary wheels while you hold down the Tape 2 key on the front panel
until a deflection of 0 dB is shown on the Stimulus VU indicator.
9. When you have completed testing of the left ear, toggle L/R Shift to switch the
signals to the left and right loudspeakers before you test the right ear.

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6 Special Tests
To go to the Select special Test menu, press Menu until the Select Func-
tion menu is displayed and then press Softkey 3, Special.
6.1 The SISI test
The SISI test (Short Increment Sensitivity Index) shows whether a patient can detect
small variations in intensity lasting 200 ms. The SISI test is not a recruitment test. A
patient who scores 60% or better for frequencies above 1000 Hz or in some cases
down to 250 Hz may have cochlear problems. Patients with normal hearing, middle
ear diseases or nerve hearing loss will score up to 20% at all frequencies.
To make the SISI test, do as follows:
1. Connect the patient response handswitch, the headphones, the optional monitor
headset (or the optional monitor adaptor with talkover microphone and monitor
loudspeaker), and the optional patient talkback microphone.
2. Switch on the electric power supply.
3. Place the patient, facing away from the MIDIMATE 602/622, in a sound-cabin, if
available.
4. Press Menu once or twice to display the Select Function menu.
5. Press Softkey 3, Special.
6. Select SISI (A) L from the Select special Test menu by pressing Soft-
key 1.
7. Select Left by pressing Softkey 1 or Right by pressing Softkey 2.
8. Instruct the patient to activate the patient response handswitch every time a short
increment in level is heard.
9. To demonstrate the test to the patient, turn the Hearing Level wheel until the
stimulus tone (shown above Softkey 3) is 40 dB or more.
10. If the display does not show 1-5dB, (the 5 dB default increment), toggle Softkey
2until it does.
11. Press the Tone Switch to begin the demonstration.
12. Make sure that the patient has understood the instructions: the Response indi-
cator lights up when the increments in stimulus tone are displayed above Soft-
key 3. The increments are not audible in the monitor headset.
13. Stop the demonstration by turning the Hearing Level or Frequency wheel.
14. Reduce the stimulus tone to 20 dB.