This story reminds me of early phonetic research on speech production from the 1920s. In order to study the position of the tongue during the production of speech a lead chain was put on the tongue streching from the tip to the back. Subjects in the experiments were then x-rayed sagittally while producing, for example, different vowels. Such x-ray pictures are available on the net (e.g.: http://commons.wikimedia.org/wiki/File:Cardinal_vowels-Jones_x-ray.jpg) and to my knowledge a well known phonetician and UCL person, Daniel Jones, who was in fact the first professor of the discipline in the UK, was involved in their production. I know more myth about this than anything else but according to this myth subjects suffered strong side effects from the lead chain and the x-raying.

You can find more information under the above link where the attached image of the sagittal x-ray pictures of the vocal tract is taken from.