In the case that exists an interaction between group and covariate. How a test comparing the mean volume of each group, like SPM does, could be done? I do not want to know if the different groups evolve in a different way with covariates, I only want to compare if groups have different volume in some regions of the brain. Or FreeSurfer does not allow to do a comparison like that? Thank you
Douglas Greve <gr...@nmr.mgh.harvard.edu> escribió: > You should first test whether there is an interaction between group and > covariate. If there is non, then you can keep the same FSGD file but run > it with DOSS (different offset, same slope). The "same slope" means that > the difference will be the same regardless of the value of the > covariate. You will need to make a different contrast. See > https://surfer.nmr.mgh.harvard.edu/fswiki/DodsDoss > > for more info > > > On 4/16/17 7:04 AM, Laura Ferrero Montes wrote: >> >> >> Dear FS team, >> I would like to make an analysis between a Patients Group and a >> Control Group. This study is focused on identifying if there are >> differences in volume between both groups. I want to regress out the >> effects of gender, age and IQ. >> >> My designed matrix has the following structure: >> GroupDescriptorFile1 >> Class PatientMale >> Class PatientFemale >> Class ControlMale >> Class ControlFemale >> Variables Age IQ >> Input subject1 PatientMale 25 110 >> Input subject2 ControlMale 30 90 >> >> I was thinking about a Contrast Matrix like this: >> 0.5 0.5 -0.5 -0.5 0 0 0 0 0 0 >> 0 0 >> However, looking for some information I discovered that it only >> compares volume of two groups at the naissance because it is only >> comparing intercepts. Therefore, how I could make a comparison between >> volumes of two groups in general? >> Thank you, >> Laura >> >> >> >> _______________________________________________ >> Freesurfer mailing list >> Freesurfer@nmr.mgh.harvard.edu >> https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer >> >> > > _______________________________________________ > 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. _______________________________________________ Freesurfer mailing list Freesurfer@nmr.mgh.harvard.edu https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer
