Re: [Freesurfer] Longitudinal stream : LME and limits of model

Hi Matthieu, no, sorry. Maybe you can find a local biostatistician who knows. A slope estimate with less time points is more uncertain than one with more time points (obviously). Also a slope estimate with time points on a line is more certain than one with time points values all over the

Re: [Freesurfer] Longitudinal stream : LME and limits of model

External Email - Use Caution Hi Martin, I come back on my previous question concerning survival bias in LME. Do you have an advice ? Best, Matthieu > Le 19 oct. 2018 à 16:30, Matthieu Vanhoutte a > écrit : > > Hi Martin, > > Do you mean that high attrition (less time

Re: [Freesurfer] Longitudinal stream : LME and limits of model

External Email - Use Caution Hi Martin, Do you mean that high attrition (less time points with time) would induce more variance on the slope estimates but this effect would be compensated by LME modeling ? Would there be proportion of early drop outs to respect in order to

Re: [Freesurfer] Longitudinal stream : LME and limits of model

Hi Matthieu, in LME it is OK if subjects have differently many time points in general. You need to ask a statistician about your specific setup, but I think it might be OK (basically less time points, means more variance on the slope estimates, but that should be considered in LME). But I am not

Re: [Freesurfer] Longitudinal stream : LME and limits of model

External Email - Use Caution Hi Martin, Thanks for your answer. I actually compare neurospychological scores at baseline between drop-out subjects and subjects with full time-points. If I ever find that drop-out subjects are more severely affected than the subjects with full

Re: [Freesurfer] Longitudinal stream : LME and limits of model

Hi Matthieu, 1) survival analysis is typically used if you want to detect if the time to an event is longer in one group vs the other (e.g. one group gets placebo the other drug and we want to know if recurrence is later in the drug group). Not sure this is what you need. The nice thing is, it

Re: [Freesurfer] Longitudinal stream : LME and limits of model

External Email - Use Caution Hi Martin, It's been a long time since this discussion but I return on this from now... The problem is that I followed longitudinal images of two groups where I had mainly missing time points at the end. Than you suggested: *If you have mainly missing

Re: [Freesurfer] Longitudinal stream : LME and limits of model

Hi Matthieu, 1. yes, LME needs to be done first so that values can be sampled from the fitted model for the SA. 2. yes, I was talking about gradient non-linearities etc that could be in the image from the acquisition. We currently don’t use non-linear registration across time points (only

Re: [Freesurfer] Longitudinal stream : LME and limits of model

Dear FS's experts, Could you answer me about questions from below inline precedent mail ? Best regards, Matthieu 2016-11-22 21:31 GMT+01:00 Matthieu Vanhoutte : > Hi Martin, > > Please see inline below: > > Le 22 nov. 2016 à 17:04, Martin Reuter

Re: [Freesurfer] Longitudinal stream : LME and limits of model

Hi Martin, Please see inline below: > Le 22 nov. 2016 à 17:04, Martin Reuter a écrit : > > Hi Matthieu, > (also inline) > >> On Nov 21, 2016, at 10:28 PM, Matthieu Vanhoutte >> > wrote: >> >> Hi

Re: [Freesurfer] Longitudinal stream : LME and limits of model

Hi Matthieu, (also inline) > On Nov 21, 2016, at 10:28 PM, Matthieu Vanhoutte > wrote: > > Hi Martin, > > Thanks for replying. Please see inline below: > >> Le 21 nov. 2016 à 20:26, Martin Reuter >

Re: [Freesurfer] Longitudinal stream : LME and limits of model

Hi Martin, Thanks for replying. Please see inline below: > Le 21 nov. 2016 à 20:26, Martin Reuter a écrit : > > Hi Matthieu, > > a few quick answers. Maybe Jorge knows more. > Generally number of subjects / time points etc. cannot be specified > generally. All

Re: [Freesurfer] Longitudinal stream : LME and limits of model

Hi Matthieu, a few quick answers. Maybe Jorge knows more. Generally number of subjects / time points etc. cannot be specified generally. All depends on how noisy your data is and how large the effect is that you expect to detect. You can do a power analysis in order to figure out how many

[Freesurfer] Longitudinal stream : LME and limits of model

Dear Freesurfer’s experts, I would have some questions regarding the LME model to be used in longitudinal stream: 1) Which are the ratio limits or % of missing timepoints accepted ? (according time, I have less and less subjects time points) 2) Is it possible to include patients that would