Sinusoidal current is evenly alternating sine wave currents having a frequency of 50hZ. It gives 100 pulses or phases in one second of 10 ms each, 50 in on direction and 50 in the other. It can be generated by reducing the voltage in 60 or 80 volts with the step down transformer.
Effects Of Sinusoidal Current:
The main action of the sinusoidal current is to to produce the muscle contraction. If it is applied continuously, tetanic contraction will occur and there is stimulation of both sensory and motor nerves which will produce tingling and needle like sensation. This is the prime reason for which the surging of current has been carried out. Once the current is surged it will produce rhythmic muscle contractions.
the pain relief occurs when sensory nerves are stimulated , by pain gait mechanism. Also when there is contraction of the muscles, this contraction has a massage like effect which not only improves the circulation of the blood butt also help in the reduction of edema by improving the lymphatic drainage.
Application Of The Sinusoidal Current:
- Explain the procedure to the patient, check all the areas to be treated either their sensations are intact or not and remove all metals.
- Soak the electrodes in the warm water, place the electrodes pads upon the motor points which have to be stimulated.
- Pads must be held firmly by means of straps.
- Do not apply over the bony prominences.
- Current should be increased slowly and according to the comfort of the patient. if any side effects are reported, stop the treatment immediately.
- Stop the current slowly by slowly stopping the machine.
Indications Of Sinusoidal Current:
- Moderate surging has an effect to cause contraction and relaxation of the muscles.
- Pain control
- Reduction of edema
- Rapid surging is beneficial in lower motor neuron lesion
- If sustained sinusoidal current is used, it will cause fatigue of reflex and muscle relaxation is obtained, so helpfull in muscle spasms and pain associated with it.
Contraindications Of Sinusoidal Current.
- A pacemaker is inserted
- Recent or nonunion fracture
- Recent scar after injury
- Over abrasion
- Hemmorhagic site’
- Near an abcess
- Any condition where muscle contraction causes a delay in the healing process.