After you have confirmed intercom contact with the particiant, you need to check that there are no metallic artefacts that will contaminate the recording.
When you have the channels scrolling idly on the “Real Time Display”, you need to do the following:
Look for abnormal activity on the channels. They should be stable.
If the channels have large perturbations, there is some metallic contaminant that will need to be removed before acquisition. This may involve the participant leaving the Scan Suite to get changed. Check with the participant if they have anything metallic on them. Typical metallic items include hair bands, metallic make-up, necklaces, belts, bras and metallic studs on trousers.
Once the channels are flat, continue with the following 3 checks.
Ask the participant to blink 3 times; you should see 3 small shifts on the traces related to the blinks.
If the channels have large perturbations, it is likely that the participant is wearing make-up with metallic components. This will need to be removed before acquisition. (This may involve the participant having to leave the Scan Suite.)
Ask the participant to look left, look right, and then look around the room - whilst keeping their head still. You should see muscle artefacts similar to those seen with the blinks.
If the channels have large perturbations, it is likely that the participant is wearing make-up with metallic components. This will need to be removed before acquisition. (This may involve the participant having to leave the Scan Suite.)
Ask the participant to take 2 deep breaths that are held for 5s before releasing. There should be little or no shift on the channels.
If the channels have large perturbations, it is likely that the participant is wearing something metallic. Typical metallic items are belts, bras, necklaces and metallic studs on trousers. These will need to be removed before acquisition. (This may involve the participant leaving the Scan Suite to get changed). N.B. If the participant is not already in scrubs, they should get changed into scrubs.
Once you have completed the artefact check, and you are confident that the participant does not have any metallic artefacts, you will be ready to Acquire. If you have done the artefact check using the DQA scan setup, you will need to re-load your scan, (see Chapter 7 Experimental Procedures).