The stimulation of muscles through electrical energy either directly to the muscles or to nerve fibers controlling such muscles has been found to be extremely desirable in a number of applications. Transcutaneous Electrical Nerve Stimulators (TENS) have been used to relax muscles and to diagnose and correct orthopedic problems. Further, electrical stimulation has been used to diagnose muscle responses in relaxation or contracture and to reduce swelling and discoloration through muscle contraction. Electrical stimulation has also been used to treat Myo-facial Pain Disfunction Syndrome (MPD) and Temporomandibular Joint Syndrome (TMJ). Selected muscle stimulation in the facial areas has been used to cause the closure of the mandible to determine the vertical position of occlusion and/or to take dental impressions. These and other applications presently used or to be used in the future are readily applicable to the electrical muscle stimulator.
Many prior muscle stimulators have required three or more electrodes with one electrode functioning as a dispersal electrode to achieve a balanced response of two or more muscles or groups of muscles, such as disclosed in U.S. Pat. No. 4,084,595; 3,983,881; 4,174,706 and and 3,797,500. Other systems have provided separation between fore and aft pulses in a dual electrode system and provide pulse separators for adjusting the time interval between pulses of opposite polarity in pairs of pulses, such as disclosed in U.S. Pat. No. 3,946,745.