Hi James
you could use techniques that compare the whole distribution of
thicknesses across subject populations. You could do a t-test or something
non-parametric like a Kolmogorov-Smirnov or use permutation testing. I'll
cc Tom Nichols so he can chime in with something more sophisticated or
specific.
cheers
Bruce
On Wed, 11 Jul 2018, James Gullickson
wrote:
External Email - Use Caution
All,
I am comparing cortical thickness between subjects with and without mild
traumatic brain injury
(mTBI). So far the contrasts in QDEC have not been significant after correcting
for multiple
comparisons. I am not necessarily surprised at this due to the heterogeneous
nature of mTBI in our
sample, i.e. we do not expect any two subjects to have damage in the same area.
I am interested in
ways to compare cortical thickness that are not dependent on a single ROI
having an effect across
subjects. One way I have tried is calculating z-scores for the values in the
aparc.stats file, and
using the number of abnormally low ROIs as a dependant variable to compare
between groups.
Is there a way to look at thickness differences at an even more general level?
E.g. by comparing the
number of vertices with abnormally low thickness? If so how would one go about
that with Freesurfer
data?
This paper takes a similar approach with DTI. I'd like to do something analogous to
their "number of
voxels with low FA" analysis.
https://www.sciencedirect.com/science/article/pii/S1053811911012146
Thanks,
James
_______________________________________________
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.
