Interferential Therapy (IFT), Physiological effects, Indications and Contraindications.

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Interferential therapy( IFT) also knows as Transcutaneous electrical stimulation application of two alternating medium frequency which is used to produce Low frequency effect on tissues and in deep structure. It was first developed by Dr.Hans Namec in 1950s in Vienna and this therapeutic device became popular in United Kingdom. It is a non-invasive, effective alternative treatment to treat chronic and post-traumatic pain.

It is mostly used to stimulate tissues that lies in deep structure within the body. In medium frequency the resistance of skin is too low which allows conduction of current easily at very depth of tissues so low frequency effect can be generate at any deep tissues without interference of skin resistance by using Medium frequency current. Interferential therapy is used in most of the countries by physiotherapists for therapeutic management of patients who suffers from low back pain.

Two medium frequency current is used simultaneously to the body through the skin these current applied in a way that they surely cross each other in the tissues and cause interference and the interference of these two medium frequency generate low frequency effect which is known as “Beat Frequency“.

Each beat frequency seems to cause excitation of peripheral nerves and give signal of a monophasic or biphasic pulse. The beat frequency is equal to a number of times each second of the current amplitude increase. The resultant low frequency current is equal to the difference of the two medium frequency current, For example:- Medium frequency current A is 4000Hz and Medium frequency current B is 4050Hz so the resultant low frequency effect will be 50Hz which is also said to be a Beat frequency.

Physiological Effect:-

The optimal frequency for most voluntary muscles is to be 40Hz-80Hz , so visceral muscles which is supplied by autonomic nervous system is generally stimulated at 10Hz-50Hz. The increased local blood circulation helps in healing and reduction of edema. It also help in relief of pain and spasm and removes damaged tissues and bring nutrients which is necessary for healing at the site if injury. The patient also feel prickling and tingling sensation due to the stimulation of sensory nerve when Interferential current is applied to their body.

• Relief in pain- Interferential current is used for the reduction of pain and prevent in joint pain. The frequency between 80Hz to 100Hz of analgesic effects helps in relief of pain and muscle spasm. Interferential therapy is more effective in chronic conditions which is musculoskeletal pain and spasm.
• Stress Incontinence- The stress incontinence is a situation where a person is not able to maintain normal passive continence of bladder when subjected to stress such as coughing and sneezing. So, Interferential therapy is very useful for the stimulation of Urinary Bladder.
• Reduction of Swelling- Interferential therapy is very effective to promote the reabsorption of edema in the tissues.

Indications:-

• Reduction of Edema.
• Relief in pain.
• Stress incontinence.
• Relief in muscle spasm.
• Stimulation of innervated muscles.

Contraindication:–

• Patients with pace makers.
• Malignancy.
• Thrombosis.
• Severe renal and cardiac failure.
• Fever.
• Anemia.
• During menstruation.
• Dermatological conditions.
• Patient with pacemakers.
• Large open wounds.
• Deep vein thrombosis.
• Arterial disease.
• Pregnancy.

Application Procedure

• Equipment Preparation- Prepare the device for the treatment, if the device is working properly select the parameter according to the condition of the patient.
• Preparation of the Patient- Screen the patient for contraindication to the Interferential current.

• Electrode Placement- Interferential therapy is either bipolar or quadripolar electrodes. The bipolar is pre- modulated current where as Quadripolar produces amplitude modulated current in the tissues. The quadripolar method ,the four electrode are used in criss-cross manner around the treatment area.
• Intensity- The intensity is increased slowly till the patient feels tingling or needle sensation at the contact area of the electrodes and also in the deep-situated area. The intensity should be increased within the patient’s comfort level.
• Duration- The treatment timing should be approx. 10-20 minutes depends upon the condition of the patient. The intensity is turned to 0 after completion of the treatment session. The electrodes are removed and skin is cleaned at the end of the treatment.

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