measurements,
x
-axis, pre-stimulation delay, stimulation duration, and
post-stimulation delay.
Threshold Detection
The Threshold Detect Delta Volume and Threshold Detection Time (du-
ration of delta compliance after the onset of a stimulus) are set at the fac-
tory to 20
m
l and 500 msec, respectively. Smaller changes in volume, or
changes occurring after this time, will be registered as N/R (No Reflex).
These measurement parameters may also be altered using the ZODI-
CON™ software.
In Version 3.
x
and later, threshold detection may also be programmed to
only accept negative reflexes, by means of ZODICON™. Two markers
(fixed cursors) may be applied to all reflex threshold records. For a de-
scription of the marker function, see §4.2.5.
4.3.1
THRESHOLD REFLEX
Reflex
Add. Threshold
(Version 4.x)
This test mode permits automatic Threshold Reflex search at six different
levels. Once a reflex has been found, the test stops. It may be continued
manually (i.e., a further test at a higher or lower level may be made), by
pressing the Tone Switch. If Additional Threshold has been selected under
Setup (§5.2.3), one additional measurement will automatically be run (at the
same level, or +5 dB, or +10 dB). Data from all stimulus frequencies (500,
1000, 2000, 4000Hz, White Noise, if Contra has already been selected) is
memorized.
Softkey 1
Press
Threshold
, or
Softkey 1
from the Threshold Menu if Advanced
Mode has been selected, to access the screen shown in Fig.4.20. Note
that, in Easy Mode, pressing Threshold might access one of the other
Threshold measurement modes if the instrument has been programmed
by means of the ZODICON™ software.
Softkey 1
Press
Softkey 1
to set the desired stimulus (500, 1000, 2000, 4000 Hz or
White Noise—note that White Noise is only available if Contra has al-
ready been selected.
Softkey 2
Softkey 2
starts or stops the test. The pushkey on the probe may also be
used to do this.
Operation Manual
47
GN Otometrics
MANUAL MODE
Chap. 4
ZODIAC 901 Middle-Ear Analyzer
THRESHOLD TESTING
4.3
Fig.4.19
Threshold sub-menu displayed
when Threshold is selected in
Advanced Mode
Содержание Madsen ZODIAC 901
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