otometrics madsen itera ii, Справочное руководство

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1. Press
WARBLE
to activate or deactivate (see Signal column
►
18 );
2. Activate Narrow Band Noise (to activate press MASK ON or MASK LOCK , to deactivate press MASK OFF ). See Masking
► 20 .)
If you use the
MASK LOCK
function to select Narrow Band Noise, you lock together the
L
and
R
levels.
8.6 Hearing Instrument Simulation (HIS)
You can use this function to demonstrate how a hearing instrument will sound.
Follow the steps described in The HIS procedure ► 79 .
A brief description
MADSEN Itera II provides an immediate way of demonstrating how helpful amplification can be. For this purpose, the basic
simulation described below is quite sufficient in most cases.
Make yourself familiar with the process before using it on the patient.
The filter characteristics are applied automatically in HIS, depending on the shape of the audiogram. The following is a
description of the HIS approach:
1. High and low frequency filters are applied to match the slope of the audiogram.
2. The steepness of the audiogram slope in dB/octave is calculated, and the HIS is set to about half this approximated
slope (according to half gain rule) using either 6 dB (less steep slope), 12 dB (medium steep slope) or 18 dB (steep
slope).
3. The frequency where the most amplification is wanted (4 kHz is the highest available) is identified, and the cut-off fre-
quency is set accordingly.
4. A gain is set to approximate half the hearing loss at the frequency selected in step 3 (half gain rule again).
5. Apply the simulation, and ask the patient whether it is comfortable or too loud or soft and adjust the reference level
accordingly.
8.6.1 The HIS procedure
Connect accessories
• Connect the various accessories you will be using for the HIS test.
Audiogram
• Use an audiogram stored in MADSEN Itera II.
or
• Enter an audiogram in MADSEN Itera II.
Prepare the patient
• Prepare the patient for the simulation, for instance by fitting headphones on the patient, and explain the process.
Select test
1. Press
SPECIAL
(twice, if needed) until
HIS
is shown on the display.
2. Press the relevant function key to select HIS .
3. One of the following messages will appear:
Otometrics - MADSEN Itera II 79
8 Special tests