​We move now to the first of several ‘reference’ electrode sites.

​If there is hair over the area discussed here, shave it before proceeding.

​Swab a 3x3cm area on the back of the participant’s left shoulder, near where the shoulder meets the curve of the neck. Many people will know this as the ‘pressure point’ area.​

Any hair over this area should be removed before the skin is prepared.

​Following the swab, abrade for 30 seconds.