User's Manual

EEG
24-17
Trend Displays
The EEG module can trend up to seven EEG parameters:
• Two magnitude parameters (MAG 1 and MAG 2)
• Two frequency band ratio parameters (FBR 1 and FBR 2)
• Spectral edge frequency (SEF)
• Peak power frequency (PPF)
• Median power frequency (MPF)
All trends should be selected before processing starts. Select the frequency band
for each trend in the Setup menu. In the figure below, the magnitude of the EEG
(MAG 1) is calculated for the frequency bands delta to beta2 and trended. One
trend parameter can be displayed at a time for each EEG channel when dual
format is off. The trend is drawn as a double wide line. A five point moving
average filter is used to smooth the data on the trend plot.
Figure 24-3: Four-channel EEG trend display
 Event Marker — Used to tag significant clinical events. Can place 52 unique
letters; a-z and A-Z. Used in identifying and recalling stored trend data.
 Artifact Flag — Artifact detection is marked by lighting a pixel on the top line.
On color monitors, artifacts will be marked with a red pixel.
 Horizontal Axis — The horizontal, or X-axis represents time. The time base is
the total time of the displayed trend, and can be set to 5-, 10-, 20- or
40-minutes. The time axis is divided into five equal segments using
intensified dots.
 Trend Line — The trend line represents the trended EEG parameter and
moves from right to left.
 Vertical Axis — The vertical, or Y-axis represents either the magnitude (in
microvolts), frequency (in hertz), or ratio (in percent). When MAG 1, MAG 2,
or EMG are displayed, magnitude is shown (values range from 2µV to
900 µV). When SEF, PPF, or MPF are displayed, frequency is shown (values
are 5 Hz, 10 Hz, 15Hz, 20Hz, 30Hz). When FBR 1 or FBR 2 are displayed,
percent is shown (values range from 10% to 900%).
 Band — The EEG band trended (Delta, Theta, Alpha, Beta1, Beta2, or
combination. Greek letters are displayed to represent each band).
 Trend Value — Shows the type of trend displayed and its numeric value.
MAG 1 indicates a magnitude trend.
 Time Base — Total time of the trend plot; ranges from 5- to 40-minutes.
To display EEG trends:
1 Touch EEG.
2 Touch DISPLAY FORMAT.
3 Select DUAL FORMAT OFF.
4 Touch TREND.
5 Select desired trend.
  

To change the trend time base:
1 Touch EEG.
2 Touch SETUP.
3 Touch TREND.
4 Touch TIMEBASE.
5 Select timebase.