The term “Electrotherapy” in this context is used in the widest sense. Some modalities (Ultrasound and Laser for example) do not strictly fall into an ‘electrotherapy’ grouping (in that they do not deliver an electric current), which is why some authorities prefer the term ‘Electro Physical Agents’ (EPA’s) which would encompass a wider range. One way that you could divide up the various modalities is into a fairly simple (‘electrical stimulation modalities’, ‘thermal agents’ and ‘non-thermal agents’. All electrotherapy modalities (with the exception of biofeedback) however involve the introduction of some physical energy into a biologic system. This energy brings about one or more physiological changes, which are used for therapeutic benefit. Clinically, it is probably more useful to work the model in reverse - determine first the nature of the problem to be addressed. Then establish the physiological changes that need to take place in order to achieve these effects.
The main types of electrotherapy are: Ultrasound, Interferential Therapy, Transcutaneous Electrical Nerve Stimulation (TENS), Pulsed Shortwave Therapy, Laser Therapy, Combination Therapy and Biofeedback. Other electrotherapy modalities are Microcurrent Therapy, Magnetic Therapy, Iontophoresis, Russian Stimulation, Shockwave Therapies and Diadynamic Therapy.