Hi Martin, Thank you for this detailed answer.
Are replacing time by score or include score as time-varying covariate leading to the same result because of looking at the same effect ? My willing would be to find patterns of atrophy rate/progression correlated with cognitive score. In context of AD which method would be the best for you ? Best, Matthieu Le 16 mai 2017 11:17 AM, "Martin Reuter" <mreu...@nmr.mgh.harvard.edu> a écrit : Hi Matthieu, one option is to replace time with score in the model. That should be straight forward. The other option is to include score as a time-varying covariate. If your score is not varying much across time and you are more interested if the average score (or baseline score) affects atrophy rates, you can also include is as a standard (fixed across time) co-variate (such as baseline age) with a time (and a group etc) interaction. Sorry, but I cannot do your design. Ultimately the model is the research question that you are asking and it is important that this is done correctly. Maybe there is a local biostats person that you can talk to? Best, Martin On 05/15/2017 08:20 PM, Matthieu Vanhoutte wrote: Hi Martin, Thank you. How should this variable be coded ? Should it be as age covariate where age at baseline is used along all time points of each subject ? Could you provide me an example of design matrix, I don't manage to see what does it look like to. Best regards, Matthieu Le 14 mai 2017 8:08 PM, "Martin Reuter" <mreu...@nmr.mgh.harvard.edu> a écrit : Hi Matthieu, yes, that is possible. Instead of group, you use a variable for your score (and interaction etc). Sometimes it may also makes sense to use score instead of time. Best, Martin > On 12 May 2017, at 10:51, Matthieu Vanhoutte <matthieuvanhou...@gmail.com> wrote: > > Dear Freesurfer's experts, > > I have searched through the mailing list but haven't found any answer to my question. > > Is it possible with LME model to make correlations between for example cortical thickness surface data and cognition scores along time ? As it is possible to test for interaction of group X time, is this also in the same way feasible to test for coognition score X time on cortical thickness ? > > Many thanks for your advice ! > > Best regards, > Matthieu > _______________________________________________ > 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 listfreesur...@nmr.mgh.harvard.eduhttps://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 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.
