CHAPTER EIGHT
ABR test procedure
88
ABR test procedure
The circle indicates the probability that an ABR response is present. The
circle is filled when there is 99% confidence that a response is present.
NLO
is an indication of the amount of data which has been collected with
the noise lower than the noise reject level.
The test will end automatically when either the circle is filled (there is a
ABR response present), when the blue NLO bar is filled (a full set of data
has been recorded but no response has been detected), or when test noise
(ABR noise) has become so low that any valid ABR would already have
been detected and so further testing is redundant.
NSE
is an indication of the amplitude of the current electrical noise level.
The lower this value is, the faster the test will be. The data measured
during this time will be ignored. If there is high noise for a consistent period
then an impedance test is automatically run and the message ‘Checking
Impedance’ will be displayed. If impedance levels have worsened
significantly since the start of the test then the test will be automatically
paused.
Pressing the left and right arrow keys displays the
Data Summary
and
Waveform Display
screens.
8.4.1
Data summary
Fsp
The Fsp is a measure of the likelihood that a response is present (see
Eberling C., Don M. Scand Audiol 1984;13:187-197
).
TC
Template correlation (TC) is a measure of the similarity of the current
waveform to a template constructed from the responses of 30 neonates
aged 0 to 6 weeks.
Time
Shows the duration of the test.