It is an interrupted direct current also called long duration current having more than 1 ms up to 300 ms or 600 ms. But the commonly used duration is 100 ms duration requires a frequency of 30 pulses/ min. If the duration increases the frequency must be reduced. The interval between the impulses should never be of shorter duration than the impulses themselves.
Pulse duration ≤ Interval duration
t 1 ≤ t 2

Physiological effects:

                               Types of Denervated muscle fibers

Neurotmesis (complete denervation)
Axonotmesis (partial denervation)
Neurapraxia (compression of nerve)

The intensity and duration of impulses in galvanic current is adequate so that it can cause a sluggish worm like contraction. When current is applied it produces sensory stimulation resulting in the feeling stabbing or burning sensation. It increases blood circulation causing erythema (redness) of the skin. Stimulation of motor nerve with such current produces contraction of the muscle supplied by that nerve.

Therapeutic effect and use:

There has been confusion over the therapeutic use of electrical stimulation for denervated muscles for the last many years. The purpose of such current is to maintain the muscles in as healthy state as possible to prevent the complication by electrically artificial contraction. Skeletal muscles have greater power of regeneration. When the muscles are denervated the following changes will occur.
  • Loss of voluntary contraction and reflex activities
  • Atrophy: Resulting in fibrosis
  • Fibrillization: Spontaneous contraction
There are considerable literatures concerning the effects of electrics stimulation. In 1987 Spieloloz concluded that it will retard the muscle atrophy and degeneration but can not prevent it completely. In 1983 Devis provide evidences that all the denervated muscle fibers must be activated to produce isometric contractions. And isometric contractions are more effective than isotonic contractions and the regular contraction should commence (start or begin or cause to start) as soon as possible.
In short value of electrical stimulation for denervated muscle is not proven and its application to gain muscle power what may be small benefits are obtain but not justified. If some of the motor units (motor end plate + motor nerve + muscle fibers) are intact galvanic current is the choice of treatment.
Interrupted direct current is still recommended for the treatment of Axonotmesis and Neurotmesis nerve repair is to be taken.

Contra – indications:

  • Cardiac pacemakers and Arrhythmias
  • Hemorrhagic condition
  • Thrombosis and thrombophlebitis (inflammation of wall of vein)
  • Early tendon transfer and repair
  • Pregnancy: On pelvic, low back and abdomen
  • Unconscious patient
  • Recent radiotherapy
  • Carotid sinus
  • Child with mental disturbance
  • Malignancy
  • Infected wound and skin lesion