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Hearing Screening Systems (Technical Manual)
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these extraneous masses by the new one and try again. The correctness of the OAE
probe insertion at TEOAE exam can be checked indirectly by the stimulus shape.
The Fig. 14 a) represents the oscillating stimulus shape. It does not match to TEOAE
registration. In the ear of adult it can be conditioned by the bad placement of OAE
probe or the atypical form of the external ear canal. In the last case the stimulus
shape should be accepted, however, try to insert the OAE probe again. The Fig. 14 b)
represents the stimulus shape at the correct placement of OAE probe for the adults.
As for the newborns, the additional fluctuations of stimulus can always be detected.
The Fig. 14 c) shows the admissible level of fluctuations of the newborn.
a)
b)
c)
Fig. 14. The stimulus shape (1).
The Fig. 15 a) demonstrates the effect of the excessive approach of the OAE probe to
the wall of the external ear canal or other barrier. The slow round low-frequency wave
following the initial sharp peaks is characteristic for this condition. In this case the
OAE probe should be reinstalled. The Fig. 15 b) shows the impact of the excessive
noise to the stimulus shape. The cause can be in too free OAE probe installation al-
lowing the penetration of the external noise to the external ear canal or noises emitted
by the patient. The typical sounds emitted by the patient include breathing, swallowing
or tooth-grinding.
a)
b)
Fig. 15. The stimulus shape (2).
5.6. TEOAE Test
After the selection of a patient in the list or entering new data about a patient, choose
the TEOAE technique and an ear for the exam performing (right or left) in the main
menu using the arrow buttons. It is desirable to perform it before the OAE probe inser-
tion to the ear of a newborn not to disturb her/him again. The OAE probe installation
should be performed according to the recommendations given in the section 5.8
“Patient Preparation for OAE Test”.
Press the “Select” button. Just after the test start, the device switches to the OAE
probe fitting control mode. The TEOAE test window appears on the display (Fig. 16).
It is divided into three parts. The stimulus shape is displayed in the top part of the