Maico MA 53, Руководство по эксплуатации

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Operating Instructions MA 53
Geba_MA53_e_13a.doc 20 851 430/3 11/11
4.5.1.3 The SISI Test
The SISI ( S hort I ncrement S ensitivity I ndex) is guided by the principle that
patients with cochlear impairment are hypersensitive to small intensity
increments. The continuous test tone is increased by 1 dB for a period of 0.2
seconds every 4.8 seconds. Whenever the patient hears the increment, he/she
presses the patient response switch. The SISI test information and the test
score are shown on the LCD-display

. The test will end automatically after
20 presented increments. The score is expressed as a percentage of ratio of
the increments heard to the delivered increments (all increments heard =
100% - no increments heard = 0%). A high score indicates a cochlear
impairment. A low score is related to normal hearing or conductive or
retrocochlear pathology.
4.5.1.3.1 Preparation of the SISI Test
To start the test select SISI in the
suprathreshold menu (as decribed before
under 4.5) and press the STIM bar

or

↔. The display

changes to the SISI
conditioning screen (as shown in picture
19).
Select the test frequency with the
frequency keys

/

or

/

. For the test you should choose the frequency
where the maximum bone conduction hearing loss is measured as described
in chapter 4.3.
Adjust test level with the level control knob

or

↕. The level should be set
to a value 20 dB above the individual hearing threshold (measured under
chapter 4.1). It must reach at least 60 dB
HL
.
Recognize that in the SISI mode the test signal is presented continuously. You
can interrupt the test by pressing the STIM bar

or

↔ for however long you
hold it down.
The patient must be instructed: "You will now hear a continuous tone. Every
time it becomes louder, immediately push the switch”.
4.5.1.3.2 Training of the Patient
Only with careful training during the following conditioning phase can a valid
test result be achieved.
The training starts with a modulation level of 5 dB. That means a continuous
tone, e.g. 65 dB
HL
, is briefly increased every 4.8 seconds for 0.2 seconds by 5
dB, e.g. to 70 dB
HL
. During the increment time the text “Tone Now” is shown
Picture 19 MA 53 display with
SISI conditioning 5dB