All of the recent research I've read is neurologically-based, and that is the prevailing theory and thought in the speech-language pathology field. Most ideas of stuttering being caused by a psychological disturbance are completely rejected. There is no doubt that psychological reactions can exacerbate stuttering, but they are NOT the cause. Even if someone lost their memory, the neurological difference is still present. Their reaction or lack or reaction to stuttering may decrease the frequency or severity of stuttering, but it is still present.