Hi Martin, Thanks for clarifying. As a follow-up, is it ok to use age or mean centered at each scan as the timing variable with the two-stage model?
Regards, Bronwyn Overs Research Assistant Neuroscience Research Australia Margarete Ainsworth Building Barker Street Randwick Sydney NSW 2031 Australia M 0411 308 769 T +61 2 9399 1883 neura.edu.au Twitter | Facebook | Subscribe From: "Martin Reuter" <mreu...@nmr.mgh.harvard.edu> To: "Freesurfer support list" <freesurfer@nmr.mgh.harvard.edu> Sent: Thursday, September 24, 2015 2:51:05 AM Subject: Re: [Freesurfer] Longitudinal Two Stage Model using mri_glmfit Hi Bronwyn, what Doug indicates here is that he thinks it is possible to do an ANOVA style analysis from a single FSGD and command (something like this: https://surfer.nmr.mgh.harvard.edu/fswiki/RepeatedMeasuresAnova ) But this would not be good in situations where you have different many time points per subjects or differently spaced time points. In fact the best way to analyze longitudinal data is to use our Linear Mixed Effects Matlab toolbox. If you have the same number of time points for all subjects and they are spaced approx. the same, the 2-stage model is usually good enough. See here: https://surfer.nmr.mgh.harvard.edu/fswiki/LongitudinalStatistics for an overview. Best, Martin On 09/22/2015 08:53 PM, Bronwyn Overs wrote: Hi Douglas, Sorry I don't know what you mean by the different mri_glmfit levels? Also how do you use two fsgd files simultaneously (I assume one file for time 1 and the other for time 2)? Kind regards, Bronwyn Overs Research Assistant Neuroscience Research Australia Margarete Ainsworth Building Barker Street Randwick Sydney NSW 2031 Australia M 0411 308 769 T +61 2 9399 1883 neura.edu.au On 23/09/2015 12:16 am, Douglas Greve wrote: BQ_BEGIN If you intend to compute a slope for each subject (first level mri_glmfit), then input the slopes to the 2nd level to test for effects of interest. Is this what you mean? It is probably possible to do this with a single FSGD file and single command line, but it is much easier to set up and understand if you use two. doug On 9/22/15 3:13 AM, Bronwyn Overs wrote: BQ_BEGIN Dear freesurfer mailing list, Is it possible to run a longitudinal two stage model from the command line using mri_glmift, instead of using the qdec gui? If so, what --y would you pass to use the preprocessed spc values? -- Kind regards, Bronwyn Overs Research Assistant Neuroscience Research Australia Margarete Ainsworth Building Barker Street Randwick Sydney NSW 2031 Australia M 0411 308 769 T +61 2 9399 1883 neura.edu.au _______________________________________________ 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. BQ_END _______________________________________________ Freesurfer mailing list Freesurfer@nmr.mgh.harvard.edu https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer BQ_END -- Martin Reuter, PhD Assistant Professor of Radiology, Harvard Medical School Assistant Professor of Neurology, Harvard Medical School A.A.Martinos Center for Biomedical Imaging Massachusetts General Hospital Research Affiliate, CSAIL, MIT Phone: +1-617-724-5652 Web : http://reuter.mit.edu _______________________________________________ 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.
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