Hi Claus,
the easiest way to do a paired t test is to run mris_preproc with the --paired-diff option. Make sure to specify time point 1 and 2 for each subject sequentially. You can do a stat test on each individual with only 2 time points.
doug
On Fri, 22 Feb 2008, Claus Tempelmann wrote:
Hello everybody,
It's some time ago that I did some group analyses for cortical thickness and after glancing through the new documentation I believe (or hope) that I still know how do do a group comparison (e.g. patients vs controls).
I have, however, never tried analyses of groups at different time points. I assume this a quite obvious problem many people have been working with and I will find more about when I really read the documentation but I hope that somebody could hint me where to look. So, I have patients who have been scanned a couple of years ago and, once again, just recently and I want to do what you would expect:
- Just look for an individual subject whether cortical thinning is
more prominent in some regions compared to others 2. Run paired tests for the cortical thickness where the pairs obviously are the data sets of the same subject at different time points.
Most likely many people have done the very same thing with freesurfer, so anybody willing to discuss the way to do it and potential pitfalls?
Thanks in advance
Claus
Claus Tempelmann email: Claus.Tempelmann@medizin.uni-magdeburg.de Clinic for Neurology II MR department Tel.: +49-(0)391-6117183 OvG University Magdeburg +49-(0)391-6117177 Leipziger Strasse 44 39120 Magdeburg Fax: +49-(0)391-6117178 Germany
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