OK, but please be cautious with what you're making of this *correlation*. Two conditions show decreased activation of Broca's, but that doesn't mean that one led to the other. There is also evidence of increased bloodflow to other areas linked to stopping motor actions, so we may be witnessing a bloodflow tug of war that has nothing to do with trauma at all (https://www.sciencedaily.com/releases/2017/12/171212125426.htm). I'm not sure you're using the words "procedural memory" correctly here, which I say only because I think there are many people who will take your point very literally. Trauma does not cause stuttering. There is no evidence for that, with the possible exception of neurogenic stuttering due to a stroke. (If there is GOOD evidence, e.g., not the 'monster study', I'm happy to take on new information.)