I'm sure a more senior person on the mailing list could give you a better answer. My impression is that 5-7 patients would be enough for a case study, i.e. "What does Network X look like in patients with Disease Y?" Such a low number of patients would probably be pushing it for a systematic analysis, especially if you don't have control subjects! But again, if the conditition you are studying has a dramatic effect on connectivity (i.e. very large effect size) then it might be enough. On Wednesday, August 15, 2012 10:17:46 you wrote: > Dear Benjamin, > > Thank you for this response. > > I must deal with some rare clinical cases (5 to 7 patients, for instance): is it > possible to use MELODIC group-analysis for this very small population? or is it > statistically irrelevant? > > Thank you. > Best, > Christophe > > > > Selon Benjamin Kay <[log in to unmask]>: > > > Christophe, > > > > That will depend entirely on your hypothesis and expected effect size. The > > final stage of analysis with MELODIC ICA + dual regression typically involves > > some sort of GLM (often a t-test) to compare connectivity between two or more > > experimental groups. The standard techniques for estimating effect size (e.g. > > Cohen's d) and power apply. Since your experimental protocol will influence > > the standard error, and thus the effect size, of your data, the best way to > > figure out how many subjects you need is to collect pilot data and estimate > > your effect size and power from that. As a very rough ballpark figure, I have > > seen ICA based publications with fewer than 20 total subjects. > > > > Hope this sets you on the right track, > > Benjamin > > > > On Wednesday, August 15, 2012 09:10:07 you wrote: > > > Dear experts, > > > > > > I would like to know the lower population size required to compute MELODIC > > ICA > > > group-analysis. > > > > > > Thank you. > > > Best, > > > Christophe > > > > > >