Freesurfer,

I want to make sure I am setting up my group analysis correctly.  I have 2 groups, one a control population and the other a patient population , that I am wanting to see where there are differences controlling for age.  I set the group as the fixed factor and I demeaned the ages and used them as the nuisance factor.  Is it necessary to demean the ages before running QDEC?

Thanks,

Crystal