Beyond Biofeedback by Elmer Green. It is an excerpt from his book. It is pretty amazing and shows with practice, it is possible to do anything even complete control of your bodily functions.
[url=http://www.swamij.com/pdf/swami-rama-beyond-biofeedback.pdf]http://www.swamij.com/pdf/swami-rama-beyond-biofeedback.pdf[/url]
This shows Swami Rama being tested for his Yogic abilities of control of his body as well as Mantra to make a needle move.