Cleveland Family Study

17.8.3.6 To Determine C3

1. Stand in front of the participant.
2. Place the zero line of the tape measure on the site for the Cz electrode placement.
3. While firmly holding the tape measure in place, allow it to drape over the left side of the participant’s head until it reaches the left pre-auricular mark.
4. Compute 20% of the total pre-auricular to pre-auricular measurement (or use your measurement guide).
5. Continue to hold the tape measure in place as you make a mark at the 20% location.
6. Without moving the tape measure, make another line, following the edge of the tape measure, to intersect the 20% mark. After removing the tape measure, extend both lines so they intersect. The point at which the lines intersect is the site for the C3 electrode placement.