Rito,

> The 205 subjects are split in two treatment arms with 100 subjects in the first one and 105 subjects in the second one.

What is the difference between these two arms?

> Do the baseline cortical thickness correlate with the corresponding cognitive score at baseline ?

This can be addressed through a simple regression model using, for example, 3dttest++.

> I am interested in testing whether the cortical thickness changed significantly across the different timepoints and does that
> relate to the change in the cognitive score. Is there an effect of treatment on this change in cortical thickness across time ?

I assume that both age and cognitive score vary across the three time points. You can use 3dLMEr to address these two questions.

The above approaches are all under the conventional mass univariate framework, so you would have to deal with the multiple testing issue. It is possible to adopt the Bayesian multilevel modeling framework so that the multiplicity issue would be resolved, but the associated program RBA would have to be modified for your situation.

Gang



Edited 1 time(s). Last edit at 07/14/2021 11:08AM by Gang.