otometrics Madsen AccuScreen PRO, Руководство пользователя

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GN Otometrics A/S 57
AccuScreen PRO User Manual Tests
Too much electrical noise can result if the infant moves or is sucking
during the test. Other electrical appliances and fluorescent lighting
in the vicinity can also cause electrical interference. A good indica-
tion of this is if the ABR bar on the display is near to the
PASS crite-
rion. If this is the case, try to improve test conditions and repeat the
test.
Consequently, before you refer the patient for further follow-up, it is
recommended that you improve test conditions and repeat the test:
• Does the probe fit well in the ear canal?
• Are the electrodes placed correctly and fit properly? Even if
the device accepts the impedance values, it is often worth
while to attempt to reduce impedance values and particularly
the impedance differences. The noise in the electrode cables
depends strongly on the impedance values.
• Is the patient well at rest and is there no muscle tension? Note
that electric muscle artifacts may arise from non-moving but
tensed muscles (isometric contraction). Please check especially
the nape of the neck for this condition.
• Are there any sources of electric noise in the environment?
Especially motor-driven devices such as pumps can cause
high noise which is sometimes accepted by the device but can
be too high, if for instance the response has a low amplitude.
In rare cases it may be worth while to relocate to another room
for testing.
• Is there much acoustic noise in the environment? High noise
might mask the stimulus.