If I wanted to do an interaction of Handedness x ROIsInteractionTerm x Age, controlling for eTIV and Sex, would I use the following contrast?

[0.5 0.5 -0.5 -0.5 0 0 0 0
0 0 0 0 0.5 0.5 -0.5 -0.5]

FSGD attached. 

Thank you so much for your time!

All the best,

Fred