in Stroke Patients
Speaking about neurophysiological monitoring in stroke patients, the general question at hand is: What do we want to see “through the monitor”? There obviously are pros and cons as to whether EEG recording is useful for stroke monitoring.
EEG as neurophysiological signal certainly reflects functional properties of the cortical neurons. But there are a number of problems with EEG recording, particularly in the stroke field:
- The EEG signal is highly complex and parameters relevant for ischemia have not been identified.
- Patients are not necessarily cooperative, leading to artifacts.
- The time window for the recording is short.
- The EEG´s spatial resolution is low.
This leads to the following requirement specifications for a stroke-specific EEG method:
- Identification of simple EEG monitoring parameters.
- Proof of their stability and reproducability.
- Attribution of clinical meaning and scientific usefulness to the parameters.
We have tried to solve the problems associated with these requirements by the following new procedure:
- 2 EEG Channels: Mastoid versus middle-point between vertex and ipsilateral ear: MCA supplied area.
- Automatical artifact suppression: amplitude — gradient — constant signal.
- EEG signal analysis:
- Instantaneous correlation between healthy and ischemic hemisphere with high temporal resolution instead of ensemble of “normal” values.
- Synchrony of peak shaped activity between 7 and 15 Hz.
- Definition of indices ISI, HIL,R
Last modified 05/18/07 11:48 Upward