Sorry I missed your comment until now, it's from papers I've read over time. There was a good post on this subreddit related to this topic, check it out: [https://www.reddit.com/r/Stutter/comments/pl522u/neuropathology_why_stutterers_brains_produce/](https://www.reddit.com/r/Stutter/comments/pl522u/neuropathology_why_stutterers_brains_produce/)