It is not possible to avoid all artefacts. However with care their incidence can be greatly reduced.
1) Place EEG electrodes at sites which minimise artefacts from muscle and eye movements and which are least likely to be disturbed by nursing procedures.
2) Ensure that electrode impedances are low.
3) Twist or bunch electrode leads together to equalise potentials induced magnetically or electrostatically. These are then attenuated by the isolation amplifier common mode rejection.
4) Anchor electrode leads firmly to the patient's head, independently of the electrode adhesive.
This prevents tugging of the leads causing electrode movement artefacts.
5) Use non-microphonic and antistatic electrode leads.
6) Always connect the reference electrode.
New Cot Artefact: It has been found that, when an overhead warming lamp is on and covered with an ungrounded metal grill, it may be impossible to get a recording from a CFAM3c monitor or an EEG machine. The cure is to connect the grill to electrical ground, provided that this is approved by your safety team.
7) Keep electrode leads away from other cables which may be carrying considerable voltages or currents or high frequency signals. If not possible try to ensure that the electrode leads cross such cables at right angles.
8) Ensure that there are no electric motors or transformers in the vicinity of the patient, the electrode leads and the isolation
9) Do not place the isolation amplifier on top of or under other electronic equipment or on metal surfaces.
10) Check the operation of the system by recording calibration signals both at the beginning and end of recordings.
