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EVOKED
POTENTIALS (ABR) STACKED
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Bio-Logic
Nav Pro Stacked ABR
A New Tool to Assist in the Assessment of Auditory Nervous
System Abnormalities Standard ABR measures have been used by
clinicians as a tool to assist in the assessment of auditory
nervous system abnormalities for the past 25 years. Stacked
ABR is a modification of standard ABR. It involves collection
of data using click stimuli mixed with high-pass masking
noise, calculation and alignment of derived band waveforms and
calculation of the Stacked ABR.
The stacked auditory brainstem response test procedure
displays activity from virtually all auditory nerve fibers
rather than just a subset.
Generating the Stacked ABR requires the derived–band and
Stacked ABR methods. A click stimulus is used to activate the
whole cochlea and the resulting response is separated into
five frequency bands by using high-pass masking. The ABRs
representing these five frequency bands are called
derived-band ABRs and are used in constructing the Stacked
ABR.
The Stacked ABR is constructed by time shifting the
derived-band waveforms so that the peak latencies of wave V in
each band coincide and then adding together these shifted
derived-band waveforms. The Stacked ABR amplitude reflects the
synchronous activity of essentially all activated neural
elements in the auditory nerve. The elimination of any
significant amount of this neural activity by an abnormality
will result in a reduction in the Stacked ABR amplitude.
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©2002
Inter-Med Technologies |
