From the paper: "Remarkably, children who recover from stuttering exhibit an increased gray matter growth rate in the dorsal premotor cortex, a region in close proximity to the dorsal..." This would further cement the first paper I cited that has clinical evidence that singing increases grey matter around speech centers in the brain. In my opinion, from my research citation and yours, this may be a strong candidate in a "cure" or mitigation of stuttering to very mild levels. I'll be singing a lot more, will see what changes in the years to come.