Electrotherapy is a process by which electrical energy is used to treat a disease or illness. The use of electricity to treat pain is an age-old method, said to have existed for more than a hundred years.

Yes, apparently there have been studies that have established the fact that chronic wounds can be treated by electrotherapy devices. Treating wounds with this method is said to help in the speeding up of wound healing.

A TENS unit is used to provide relief from pain. It works through an application of electrical current through the skin by using two or more electrodes. It is supposed to be a safe and non-invasive method of reducing pain.

A TENS (or Transcutaneous Electrical Nerve Stimulators) unit is an electrotherapy device which applies electrical stimulation to nerves and muscles via adhesive pads placed on the skin. It is powered by a battery.