Analgesic Muscle Stimulator

Electric muscle stimulators, or EMS, can be useful tools for rehabilitation therapists and other medical practitioners. Thought to reduce pain and encourage circulation, these devices pass an electrical current through the body, potentially exciting nerves and muscle cells. These machines are cost-effective, and may be a viable alternative or adjunct therapy to prescription medications. If you have chronic or acute muscle or nerve pain, talk to your doctor or therapist about EMS treatments.

Physiology

Muscle stimulation is influenced by electricity, mostly through nerve impulses and substances called electrolytes that conduct electrical currents. According to the Nicholas Institute of Sports Medicine, nerve impulses pass down nerve fibers where they trigger acetylcholine release, which in turn binds to muscle membranes. Acetylcholine triggers an action potential in the muscle, or the means to conduct an electrical current. Calcium, an electrolyte, then begins the process for muscle contraction. The theory of electrical stimulation for therapeutic purposes has been widely studied because muscle movement is largely electrical.

History

Although electric stimulation seems like a technological advancement, it has actually been in use for thousands of years. Electric eels were used by Egyptians to treat a variety of ailments, and according to an article published in 1975 in "Medical Instrumentation," torpedo fish were used in the first century A.D. to treat gout. Throughout the ensuing centuries, the fascination with electrical currents continued. With the advent of wires and batteries, devices were more easily accessible to doctors interested in pain management. An article published in 2008 in the "Annals de Readaptation et de Medicine Physique" states that after the 1960s, progress in both electronics and data processing, as well as the miniaturization of devices, helped pave the way to the electrostimulation techniques used today for rehabilitation.

Types

There are a variety of muscle stimulators in use as of 2010. Transcutaneous electrical nerve stimulation, or TENS, units, interferential units and galvanic units are used by physicians and therapists to attenuate different pain disorders. Each type utilizes electrodes, or conductors, that pass a low-grade electrical current into targeted muscles. TENS units use alternating current in a variety of frequencies, amperage and voltage to primarily target nerve-related pain conditions. Interferential units work by passing two or more alternating currents through four or more electrodes attached to your muscles. The galvanic units utilize a direct current, and are used for acute injuries.

Benefits

Because EMS units apply an electrical current directly to muscles, they are often used in therapeutic settings to stimulate involuntary muscle contractions in conditions where voluntary contraction is not possible. Living-with-back-pain.org states that providing stimulation to unused muscles can potentialy prompt increases in circulation, which brings oxygen and other needed nutrients to muscles. Without use or stimulation, muscle tissue can breakdown. Rehabilitation and sports medicine centers often utilize EMS for injuries, purportedly to speed recovery.

Research

The "Clinical Journal of Pain" published a study in 2008 that investigated the analgesic, or pain relieving, effects of TENS stimulation on post-laparoscopic ligation patients. The study found that both high and low frequency TENS currents signficantly decreased post-operative pain. The researchers concluded that, in combination with pain medications, TENS can be an effective means to alleviate pain after surgery. In critically ill patients, multiple organ failure, sepsis and immobilization can lead to losses in muscle mass. According to a study published in 2009 in "Critical Care," EMS treatments helped to preserve some muscle mass, preventing atrophy, in patients with critical illnesses.