History of a TENS Unit?

Electrical stimulation for pain control was used in ancient Rome, 63 A.D. It was reported by Scribonius Largus that pain was relieved by standing on an electrical fish at the seashore.[3] In the 16th through the 18th century various electrostatic devices were used for headache and other pains. Benjamin Franklin was a proponent of this method for pain relief. In the nineteenth century a device called the electreat, along with numerous other devices were used for pain control and cancer cures. Only the electreat survived into the twentieth century, but was not portable, and had limited control of the stimulus.