Operating Instructions MI 34 / MI 34 H
GEBAmi34e.11a.docx
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850 232/14 08/11
When the stimulus presentation and measurement are made in the same
ear by means of the probe, this acoustical reflex is referred to as an
ipsilateral acoustic reflex. When the stimulus presentation and
measurement are made in opposite ears, the reflex is referred to as a contra
lateral acoustic reflex.
For best results, this reflex measurement is automatically conducted at the
air pressure value where the compliance peak occurred during the
tympanometric test. Stimulus tones of varying intensities at 500, 1000,
2000 or 4000 Hz are presented as short bursts. If a change in compliance
greater than 0.05 ml is detected, a reflex is considered present. Because this
is an extremely small compliance change, any movement of the probe
during the test may produce an artifact (false response). The level at which
a reflex occurs is recorded as a number, as PASS/FAIL and in graph form.
If the tympanometric results display any abnormal findings, the results of
the acoustic reflex testing may be inconclusive and should be interpreted
with care. If a ”flat” tympanogram is observed, showing a non-mobile
middle ear system, the MI 34 will not perform an acoustic reflex test.
Theoretically, a compliance peak is necessary to observe a reflex at peak
pressure.
