Yea, the real hard part is figuring out how to model the twins that are split
between groups. You might be able to create a bunch of groups. If you've
already created a design in FSL that you like, you can extract the design
matrix and use it in mri_glmfit with the --X option. Not sure about correcting
for multiple comparisons though
On 3/8/19 3:13 AM, Julian Macoveanu wrote:
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Thank you for the reply.
The original idea was to have an ANOVA with a group factor “diagnosis” with
three levels. We could use an F-test to check for an effect of diagnosis and
then perform 3 pairwise group tests (LR vs HR, LR vs ILL, HR vs ILL).
Would it help to only implement the two-sample group tests? However, the
critical issue to account for correlated data remains since about 80% of the
subjects have their co-twin in the same group. The idea behind the model that
has a variable with 1s for each twin pair is to model out each pair’s mean. I
implemented the model I described in the FSL GLM and estimated with FEAT for
the functional data of the group. The second option I had was to perform a
permutation based estimation as implemented in PALM and restrict the
permutations to between pairs and single subjects.
Would any of these options work in FS? Maybe clustering the subjects somehow?
Julian
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