Operator's Manual

Table Of Contents
Home Screen Trend Graphs
BIS™ Advance Monitor
ASYM is displayed only for four-channel monitoring.
Two examples are show in Figure 34. ASYM Graph on page 103:
A value of 60 LEFT for ASYM at a certain point in time would mean that the
EEG power in the left hemisphere is 60% higher than it is in the right
hemisphere at that point in time. On the graph, it would be displayed as a
peak at the line representing the level of 60 in the upper part of the graph;
the upper part of the graph is indicated by an L icon, representing the left
side of the brain.
A value of 32 RIGHT for ASYM (at a different point in time) would mean that
the EEG power present in the right hemisphere is 32% higher than it is in
the left hemisphere at that point in time. On the graph, it would be
displayed as a trough at the line representing the level of 32 in the lower
part of the graph; the lower part of the graph is indicated by a R icon,
representing the right side of the brain.
Figure 34. ASYM Graph
Label Function Description
1
Y vertical axis -
percent
The Y vertical axis indicates the power of
the EEG signal, with lines indicating levels
for power in each hemisphere. The ASYM
value can appear either in the upper (left)
part of the graph, indicating that most of
the EEG power resides in the left
hemisphere, or in the lower (right) part of
the graph, indicating that most of the
power resides in the right hemisphere.
2 60 LEFT indicator
Indicates a point at which the EEG power
in the left hemisphere is 60% higher than
the EEG power in the right hemisphere
8
9
7
2
1
3
4
5
6