Effects of a 2-, 3- and 4-electrode stimulator design on current dispersion on the surface and into the limb during electrical stimulation in controls and patients with wounds.

Electrical stimulation is a widely used modality in the field of physical therapy and exercise physiology. The most common method for the application of electrical stimulation is a two-electrode system where one electrode is the source and the other is a reference. However, recent studies report that a more effective delivery system can be achieved if more than two electrodes are used. In the present investigation, the circuitry to deliver electrical stimulation through a 2-, 3- or 4-electrode delivery system was designed. The system was evaluated by its ability to deliver current on the surface of the skin as well as deep into the quadriceps muscle in six control subjects and in and around wounds in six other subjects. The results of the experiments showed that much better depth of penetration was achieved in a 4-electrode system (one electrode was on the opposite side of the limb and three electrodes were on top of the limb) than in either a 2- or a 3-electrode delivery system. In non-wounded skin, given the same current from the stimulator, the current in the quadriceps muscle was found to be double with a 4-electrode versus a 2-electrode system. In wounds, this same finding was seen. Here, blood flow, an indicator of the effectiveness of electrical stimulation in wounds, was three times higher if a multi-channel stimulator was used versus a 2-channel stimulator. Thus a multi-channel electrical stimulation system is more effective than a 2-electrode system.