IntroductionChapter 1

Electrotherapy is an ever-advancing field. The use of electricity for therapeutic purposes has grown up in recent years and now includes a wide variety of apparatus and equipments. A large number of therapeutic modalities for treating several disorders are now in use.

Electrotherapy is the treatment of various ailments by electro physical modalities which include low frequency, medium frequency, high frequency currents, Actinotherapy and Heliotherapy.

The Greek word “Actis” means “a ray” and the treatment by rays is called as “Actinotherapy” (using lamp as the source of light).

Helio means sun and therapy means treatment. The use of natural sunlight for therapeutic purposes is better known as Heliotherapy.

Faradic current: Faradic type current is short duration interrupted direct current with pulse duration of 30.1-1ms and frequencies between 50 and 100 Hz, used for the stimulation of innervated muscles.

Galvanic current: It is interrupted by unidirectional DC having long duration pulses that means more than 3 milli second. Frequency of this current is 30 cycles per second.

Transcutaneous electric nerve stimulation (TENS): Transcutaneous electrical nerve stimulation is the application of low frequency currents in the form of pulsed rectangular currents through surface electrodes on the patient's skin to reduce pain. The effect and use of TENS depends upon gait control theory and pain modulation.

Inter-ferential therapy (IFT): It is the application of two medium frequency currents (like 4000 Hz and 3900 Hz) to produce a low frequency effect.

Russian currents Russian currents are evenly alternating currents with a frequency of 2500 Hz (between 2000-10,000 Hz). These are applied with a series of separate bursts, i.e., polyphasic AC waveforms.

Short wave diathermy: It is the treatment by heating of tissues and is application of electromagnetic short waves. The name itself indicates treatment with waves of short-wave length. Short wave diathermy is used in 4medical field having frequency 27.12 MHz and wavelength of 11.06 metres. The less common frequencies and wavelengths used are 40.68 MHz and 7.5 m and 13.56 MHz and 22 m.

Microwave diathermy: Microwave diathermy is having wavelength between infrared and short waves. It has frequency of 2450 MHz and wavelength of 69 cm, which is used in physiotherapy. The other frequencies and wavelengths used therapeutically are 915 MHz or 433.92 MHz and 32.79 cm or 69 cm respectively.

Ultrasound is the method in which treatment is done by inaudible sound waves of very high frequency, i.e. 0.8 to 3.0 MHz and the wavelength 0.2 nm.

Infrared rays are electromagnetic waves with wave lengths of 750 nm to 4,00,000 nm. Any hot body emits infrared rays. For example the sun, gas fires, coal fires, electric fires, hot water, etc.

UV Radiation is electromagnetic waves which is invisible to human eye with wave length between 10 nm and 400 nm, ultraviolet lies between visible light and X-rays in the electromagnetic spectrum.5

LASER is light amplification of stimulated emission of radiations. Laser rays are electromagnetic radiations. These are single colored (mono-single, chromatic-colored).

Paraffin wax bath therapy is an application of molten paraffin wax on the body parts. The temperature of the paraffin wax is maintained at 40 to 44°C, whereas its melting point is 51 to 55°C.

Hot packs are the packs which are immersed in an apparatus called Hydrocollator. They provide superficial moist heat to the part where applied. They contain the substance which absorbs heat like silica or gel. They are stored in a thermostatically controlled water bath inside the equipment. The temperature inside the hydrocollator ranges between 65 and 80°C. The aim of the hydrocollator pack is to rise the body temperature at 40 to 45°C.

Electric heating pads are used to provide raised temperature of 40 to 45°C to the body parts. It contains an electric heating element inside it and is regulated by a resistor or rheostat. They provide superficial heat to the part where applied. The transmission of heat is by 6means of conduction. The main advantage of using electric heating pads is that they can be used at home by the patients themselves and are cheaper and flexible.

Hydrotherapy refers to the therapeutic use of water as contrast bath, whirlpool bath and pool therapy and ice bath.

The principle of contrast bath therapy is to combine the effects of both hot as well as cold bath together. The part is immersed alternatively in hot and in cold water tanks. The temperature of hot water ranges from 36 to 45°C and the cold water from 15 to 20°C. The application of cold and hot bath results in alternate periods of vasoconstriction, and vasodilation. This reduces nerve conductivity as well as muscle spasm and spasticity.

The application of ice produces vasoconstriction which reduces nerve conductivity resulting in relief of pain, swelling and spasm.7

The use of whirlpool bath has becoming an increasingly valuable means of physiotherapeutic treatment. The principle of whirlpool bath therapy is to combine the effects of temperature with the mechanical effects of the water. Warm whirlpool contains water at temperature ranges between 36 and 45°C and a jet of water or air stream is allowed to produce turbulence in the water.

The use of water for therapeutic purposes is taking place since ancient times. It is used for muscle strengthening, mobility of joints, co-ordination and balancing. Movements downward in the pool are resisted by buoyancy. Fluid of different densities may be used to increase the effect of buoyancy.