Maico MB 11 Classic, Руководство по эксплуатации

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Operation Manual MB 11 Classic
8100498-4_OM_MB11_Classic_3.18_EN_16a.docx 52 01/16
users of the advanced feature of Standard ABR and Time Step stimulus
should decide whether they prefer to use Vertex/Ipsilateral mastoid
placement of the electrodes and position the electrodes on the patient in
accordance with that preference.
8.1 Testing with the Time Step Stimulus
8.1.1 The Time Step Stimulus
In the “Standard ABR” test the evoked potential is measured for individual
clicks of a defined sound intensity. Instead of individual clicks, the step
stimulus uses “packets” of 6 clicks following each other very rapidly in which
the intensity increases in 10 dB increments for each click in the packet
(figures 32 and 33). As the entire "click packet" is presented in only 25 ms,
the patient is not aware of the complex composition but it is still processed
with a high level of time precision in the brainstem. If the six sound pressure
levels of the click chain are arranged in such a way that the hearing threshold
lies within this sound pressure range, then a single averaging suffices to
"objectively" determine the hearing threshold, as those clicks below this
level of course do not evoke any potential.
Figure 32
Stimuli Presentation with Standard ABR and Time Step Stimulus ABR