[Freesurfer] Fwd: Case-controls study !

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Hi FS experts,

I was wondering if someone could help me get the following issue resolved.

Thanks.

---------- Forwarded message --------- From: Martin Juneja mj70481@gmail.com Date: Fri, Dec 8, 2023 at 11:03 AM Subject: Case-controls study ! To: Freesurfer support list freesurfer@nmr.mgh.harvard.edu

Hello FreeSurfer experts,

In my case-control study, I have a dataset of 5 healthy controls (HCs) and one patient (PAT). I was wondering if there is any way to perform GLM for PAT > HCs on brain morphometry data.

When I tried to follow instructions from here: https://secure-web.cisco.com/1aK-KNfU8HH_e-fpaIAGAkK_0d2hcDIl4JpjyDUomASQEQQ..., the mri_glm fit command gives me the following error:

Class Size and Means of each Continuous Variable

1 HC 5 24.2000 0.6000

2 Tumor 1 50.0000 1.0000

ERROR: Class Tumor has 1 members. With 2 variables and using DODS, you need at least 3 members

It seems at-least three subjects are required in the Tumor category - because I have age and sex covariates in my fsgd file.

I was wondering if there is any way to still perform the above GLM analysis or any other alternatives available to compare HCs vs one PAT.

Thanks!