Totally Fluent. I love this topic. I wonder why we don´t discuss this more enough. Is it the breaking point with the debate if in deed stuttering is due neurological anomaly or not. From your survey you can tell that 90% of people (including no-stutter and less) while alone have some degree of improvement regarding their fluency. These are considerable numbers. Ultimately, it is not being alone that make´s you fluent but the thought that no one can hear you. It is very diferent. You can be alone but thinking on the presence of someone and stutter anyway (10%). **¿Have you seen the movie "I am Legend" by Will Smith? I would bet my life that if a PWS would be on that situation, completely alone for 5,10 years, his brain will absolutely know that no one is around. Stutter gone.** It make´s total sense. Imagine someone with a rapped associate trauma. He need´s to just remember or think the about the situation and probably his/her body will explode on emotions and reactions (like basal ganglia dysfunction as you said). It is the though not the situation. And we stutter on the presence of other people that for sure.