[Eeglablist] MPT study on ERP for three groups and three conditions

[Mohammed Jarjees]

Dear EEGLab team



I am doing MPT study on ERP. I have 3 groups and 3 conditions. Groups are healthy people and two groups of patients and conditions are different types of movements. I have equal number of participant n each group. So I use MPT to find differences between healthy people and patients and need to be sure that what I see is a consequence of pathology rather than unbalanced dipoles per group.



>From MPT theory I know that if we have one group and several conditions, it is not necessary to have every single subject in each domain. One might argue that the same should imply if we have different number of groups. I am however not sure if I can have a domain I which I have twice as many healthy people (and their dipoles) than patients. (MPT ignored dipoles of half of patient group). I tried changing correlation from 0.6 to 0.8 but this did not affect the number of dipoles.



What is the exact criteria for grouping dipoles (base on ERP)?

Paper of Bigdely-Shamlo et al. 2014 Neuroimage, explains that the method is based on significant location selection.

I just wonder if that can be a strong argument to explain why MPT removed data of half patient group and whether a comparison between patients and healthy is still valid?



Best Regards



Mohammed

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