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3.8 TYMPANOMETRY ONLY MODE
To do only Tympanometry, press the TYMP button. The display will
immediately show the format for the tympanogram along with the sum-
mary information headers: ECV, cm
3
, daPa, and GR. The default scale
for compliance is 1.5 cm
3
. If a compliance peak greater than 1.5 cm
3
is
measured, the TM 262
TM
Auto Tymp
TM
automatically scales the compliance
axis to 3.0 cm
3
so that more of the tympanogram data can be seen.
Determine which ear is to be tested and select the appropriate ear but-
ton, RIGHT or LEFT , so that the test results will be properly
labeled. Examine the ear canal to determine the appropriate size eartip.
Push the eartip as far down on the probe as possible, so that it is flush
against the probe. Position yourself at eye level with the test ear. The
blinking green lamp indicates that the TM 262 is ready to begin the
test. Place the probe against the entrance of the ear canal so that its
opening is completely covered, so that no visible leaks are apparent.
Once the TM 262 determines that a volume between 0.2 cm
3
and 6.0
cm
3
is present, the test sequence begins and the green lamp changes
from a blinking to a steady state. From this point on, hold the probe
securely in this same position without any hand motion. Keep your
eyes on the probe and the individual’s ear.
At the start of the test, the pressure system establishes a pressure of
+200 daPa within the ear canal. When this pressure is achieved, the
TM 262
TM
Auto Tymp
TM
makes a measurement of Ear Canal Volume
(ECV). This information is valuable since it indicates if a good seal has
been established and it helps differentiate between two similar tympan-
ograms (i.e., a fluid-filled middle-ear system and a perforated tympanic
membrane). After the Ear Canal Volume (ECV) is obtained, this compliance
value is subtracted from the remaining compliance measurements so that
a direct reading of the tympanogram compliance peak is possible.
The pressure sweep begins at the starting pressure of +200 daPa and
proceeds in a negative direction at a rate of 600 daPa/second. Mea-
surements of compliance are made continuously as the pressure sweep
continues in a negative direction. The slope of the tympanogram
increases as the measurement approaches the compliance peak. This
signals the TM 262 to slow the rate of pressure sweep to 200 daPa/
second to ensure a more accurate reading of the compliance peak.
After the peak compliance and pressure values are detected and
stored, the tympanogram dips downward toward the baseline and
the pressure sweep rate returns to 600 daPa/second. The tympan-
ometric sweep ends automatically when the compliance value returns
to baseline and the pressure is at least –100 daPa. Only when the
middle-ear pressure is very negative is it necessary for the pressure
sweep to continue all the way down to –400 daPa. This automatic stop
feature eliminates unnecessary pressurization of the ear and shortens
the test time. When the test is completed, the solid green lamp turns
off and the tympanogram results are displayed on the LCD.
TYMP
L
R
