HI,
I solve my problem. The FreeSurfer GLM model is easier to use than SPSS GLM. I had force SPSS to look at my model by selecting group differences between group1 and group2 and look at interactions between the three groups. I then got similar results as in FreeSurfer glm for the group differences
Best regards
Knut J
On 07/31/2012 09:37 AM, Knut J Bjuland wrote:
Hi, I have calculated the group differences for volume using both FreeSurfer GLM and SPSS GLM. I have used gender and group as fixed factor and intercranial volume and age at MRI scan as covariate.
GroupDescriptorFile 1 Title group_difference_between_group1_and_group2_gender_age DeMeanFlag 1 Class Group2Male Class Group2Female Class Group1Male Class Group1Female Variables ICU Age
I used this as fsgd heading, and I used this contrast vector 0.5 0.5 -0.5 -0.5 0 0 0 0 0 0 0 0 to be able to control for gender difference and difference due to age and ICU. I get difference results between SPSS and Freesurfer. I think this is strange since I used the same data both in FreeSurfer GLM and SPSS glm. Is there anything I have done wrong? I have used both univariate and multivariate in SPSS glm.
Best regards Knut J _______________________________________________ Freesurfer mailing list Freesurfer@nmr.mgh.harvard.edu https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer
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