Yes as said in the research paper, stuttering can cause something called "small t" traumas through bullying, lower self esteem etc and EMDR helps with trauma including "small t" traumas that accumulate over time. And personally i found the same thing happened with me, emdr helped me become more confident and not worry as much about IF i do stutter which caused the tension to go down which in turn made myself stuttering less often and less severe There are only a few studies linking PTSD and stuttering together as far as i saw only around 4 but i do think they will be linked a lot more in the future especially as you said C-ptsd as it is from multiple traumas not just one