Differences

This shows you the differences between two versions of the page.

--- fmriquality [2010/06/17 19:09] – integrated the information in the QA page jochen
+++ fmriquality [2010/10/26 19:23] – jochen
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 ===== Motivation =====
-There are several things that can go wrong during the acquisition phase (scanning) of a subject, some of which severely impact the usability of a subject's dataset. While any given project (study) is still in the stage of data collection (subjects are still being scanned), there is always the chance to decide that a particular subject might introduce too much noise into the eventually performed group statistic and should be discarded (and in this case replaced by another subject).
+As said on the [[Processing stream - quality assessment|quality assessment]] page, this function is used to determine whether or not a given dataset (run) is suitable for subsequent data analysis.
-Relevant for that decision could be one of the following issues:
-  * the subject had to exit the scanner before the experiment was completed -> usually such a dataset needs to be discarded
-  * the subject couldn't restrain from moving their head during the experiment -> depending on how difficult it is to find a replacement subject, it is advised to discard such a dataset
-  * the scanner produced disproportionally strong noise in the data -> if possible, such a dataset should also be discarded
-Of course there are still many other possible reasons to discard any given subject (e.g. a score on a questionnaire/behavioral measure indicates that the subject does not fall into the distribution of the examined population of subjects), but especially the second and third issue mentioned above can be detected even before entering a subject's dataset into any given group analysis.
-This function, ''fmriquality'' allows to assess some of the more general quality measures in a unified way.
 ===== Requirements =====