Rehabilitation therapy in veterinary medicine often includes the use of electrotherapy devices, which Sheila Schils, PhD, MS, described at the 2009 American Association of Equine Practitioners convention, held Dec. 5-9 in Las Vegas, Nev.

Electrotherapy technology, available since the 1960s, is useful to manage pain, improve range of motion, decrease edema (fluid swelling), improve motor control and strength, reverse muscle wasting, deliver blood flow, and serve as a vehicle for iontophoresis (the use of electrostimulation to drive a drug through intact skin).

Schils, currently a principal of EquiNew LLC, an equine therapy company, explained that a veterinary electrical stimulation modality must be correctly designed to produce the desired results, because animals will not necessarily accept a system that may be well-tolerated by humans. She reviewed and compared the major categories of devices available to help equine veterinarians better understand the attributes of each system.

The first device Schils described uses transcutaneous electrical nerve stimulation (TENS) for producing sensory stimulation to "gate" the pain signal, while stimulating release of endogenous endorphins. A TENS device is often used for electroacupuncture, its action visible as continuous muscle twitches.

Next she described interferential electrotherapy as an alternative to TENS for suppressing pain. This device combines two higher frequency wave forms to create an interference pattern for sensory stimulation, but without visible twitching.

Schils then mentioned the high-voltage, pulsed-current stimulators that produce unidirectional continuous mov