Electro-analgesia.

Between May 1975 and March 1976, 19 patients with pain or hypersensitivity, or both, in the distribution of a peripheral nerve were treated with electro-analgesia in the physiotherapy department of Sydney Hospital. The rationale for this treatment is the work of Melzack and Wall (1965). The current selected was that used by Meyer and Field (1972), a unidirectional square wave current with pulse length of 0.1 millisecond at a frequency of 100 Hertz. The machine used was a GRASS S48 stimulator, which is a highly accurate instrument. The electrodes were twin silver plates, 15 mm x 7 mm approximately, covered with lint mounted with a space of 2.5 cm on a piece of perspex (Fig. 1) or silver wire covered with lint for use on fingers.