Correcting A Threshold Invalidated By Contralateral Bone Conduction; Locking The Masking Level To The Hearing Level; Testing Above 110 Db Hl; Setting A Minimum Tone Presentation Time - otometrics Madsen Midimate 602 Quick Manual

MIDIMATE 602 & 622 Diagnostic Audiometers
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.
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