Operator's Manual

Table Of Contents
Home Screen Trend Graphs
100
BIS™ Advance Monitor
Label Function Description
4 Y axis Y axis showing the EEG amplitude
5 EEG trend line/s One EEG trend line is seen if scale is 2µV/mm;
with other scales, one graph will be displayed for
each channel
3.9.4. DSA Display
To display DSA on the home screen, select a display option that includes DSA as
described in 3.12 Home Screen Options on page 121.
The DSA reflects the EEG as a function of frequency (in Hz, on the Y vertical axis), time
(on the X horizontal axis), and power (indicated by color).
Blue shading indicates low EEG power and red shading indicates high EEG power.
The color guide at the top of the DSA graph provides detailed shading information.
Power indicates the strength of a particular frequency in the EEG signal, so, for
example, if the DSA graph shows red shading at a specific frequency, say at the Delta
wave frequency, it would mean that the EEG signal is largely composed of Delta
waves at those points that show red (that is, high power) shading.
The frequency range (bandwidth) indicated by the DSA graph on the Y axis is 0.5 - 30
Hz, with each vertical line corresponding to frequencies for Delta (0.5-4Hz), Theta (4-
8Hz), Alpha (8-13Hz) and Beta (13-30 Hz) waves respectively. For the 4-channel
system, the graph is shown for each brain hemisphere.
The DSA graph also displays the MF and SEF trend lines:
MF is the line under which 50% of the EEG power lies. This information helps identify
the frequency of the EEG signal.
SEF is the line under which 95% of the EEG power lies. This information helps identify
the dominant frequency/s of the EEG signal.
In four-channel monitoring, a DSA graph is displayed for each hemisphere.