I think doctors use mostly either the sterilized needles, as mentioned in the article, or they use this thing that looks like a ballpoint pen, but clicks out a filament like a piece of fishing line, to do very much the same thing. I know that's what they use for diabetic patients, to test the sensitivity in their feet. But I also had a doctor who used a tuning fork to test my feet. He would strike it and as it vibrated, he would test my feet. He said that was common for neurologists to use to check for impairment, too.