Freesurfer Support,

I'd like to create a design matrix for a group analysis outside of the DODS
and DOSS models. I understand that in order to do this the -X flag must be
used. However, I have been unable to find examples of how to do this.

I am hoping to reveal a difference in thickness or gyrification amongst a
clinical population. The data set contains two factors: diagnosis, and
study site and one covariate: age. Diagnosis has two levels: controls, and
patients. Study site has four levels, one level for each location the data
has been collected from.

What I would ideally like to do is:

1) Take into account offset differences amongst diagnosis and study site.

2) Allowing a difference in age slope amongst the diagnosis levels

3) Modeling the age slope as the same for the study site levels

My FSGD file is designed as follows

Class SITE 1-Control
Class SITE 1-PATIENT
Class SITE 2-Control
Class SITE 2-PATIENT
Class SITE 3-Control
Class SITE 3-PATIENT
Class SITE 4-Control
Class SITE 4-PATIENT
Variables age_at_scan

study site levels = 1,2,3 and 4
diagnosis levels = PATIENT and Control
age_at_scan = covariate age

Any advice would be greatly appreciated.

Respectfully,

Tim

-- 
Timothy Hendrickson
Department of Psychiatry
University of Minnesota
Mobile: 507-259-3434 (texts okay)
_______________________________________________
Freesurfer mailing list
Freesurfer@nmr.mgh.harvard.edu
https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer


The information in this e-mail is intended only for the person to whom it is
addressed. If you believe this e-mail was sent to you in error and the e-mail
contains patient information, please contact the Partners Compliance HelpLine at
http://www.partners.org/complianceline . If the e-mail was sent to you in error
but does not contain patient information, please contact the sender and properly
dispose of the e-mail.

Reply via email to