I would hate to disagree with Norman Doidge. He is a brilliant guy and definitely on the right track. Was Doidge specifically discussing stuttering or was he speaking in general? People have all sorts of neurological problems (Parkinsons, Alzheimers, ADHD, strokes, etc) and you just can't rewire your brain to make them go away. Impossible. Much better to seek some sort of accomodation be it medications, counseling, a prosthesis or whatever helps the person who stutters. As to your speech getting worse after watching a severe stutterer there can be many reasons for this. Again the opposite would be watching a severe stutterer who is now fluent. If that will make you fluent, that is great. However most of us would need much more to become fluent