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Original Editor - Abdallah Ahmed MohamedTop Contributors -
Introduction[edit | edit source]
Faradic current is a short duration interrupted direct current with a pulse duration ranging from 0.1 to 1 ms with a frequency of 50 to 100 Hz. Faradic current is surged to produce tetanic contraction and relaxation of the muscle. Treatment with faradic current also known as faradism.
Difference Between Faradic and Galvanic Current[edit | edit source]
Faradic Current[edit | edit source]
Faradic is an interrupted direct current that has a frequency of 50:100Hz with a pulse duration from 0.1-1MS. This frequency and duration cause contraction and relaxation in innervated (nerves intact) muscles. It does not work on muscles that are denervated muscle; to cause the same effect a short pulse duration would be required. When applying faradic stimulation, the stimulation of the sensory nerve can result in the patient experiencing a pricking sensation due to the short duration of the pulse. The stimulated nerve causes a reaction in the motor fibres which makes the muscle contract. The different types of waveforms are:
- Trapezoidal surging - the impulse increases gradually followed by a gradual decrease. This is used in mild to moderate injuries.[Ref]
- Triangular surging - forms trapezoidal surging. Used for what [Ref]
- Sawtooth surging - the impulse increases gradually then suddenly falls. This is used in severe injuries.
Galvanic Current[edit | edit source]
is interrupted direct current has frequency 30 Hz with pulse duration 1Ms and more. This type of current used for muscle not have the nerve because of injury of the nerve. When applying galvanic, the denervated muscle responds to this stimulus because of the long pulse duration. The denervated muscle does not respond to faradic because pulse duration is short. The patient with faradic feel of burning sensation
Types of galvanic waveform
Rectangular surging: the current turn on and off intensity abruptly.
Trapezoidal surging: it slow rise and slow fall.
Triangular surging: it raises slowly, plateau’s and then falls slowly.
Sawtooth surging: the gradual rise of current and abruptly falls.
Physiological Effect[edit | edit source]
- The physiological effect of faradic and galvanic are almost the same except faradic for innervated muscle and galvanic for denervated muscle.
- Both current increase blood flow to the area treated that make the area slight redness due to vasodilatation. Also, both current make contraction the muscle similar to voluntary muscle contraction. To prevent fatigue the faradic allow the muscle to relax after contraction.
- The faradic and galvanic current increase metabolism and remove waste products and bring more blood supply and nutrients to muscle thus increase demand of oxygen and nutrients to the muscle.
- Electrical stimulation will re-educate muscle action.
- The electrical stimulation can help to minimize the extent of muscle atrophy.
Indication[edit | edit source]
- facilitation of muscle contraction when inhibited by Pain.
- Muscle re-education: muscle contraction is needed to restore the sense of movement.In cases of flat foot or in muscle transplantation. the brain appreciates movement not muscle actions so current should be applied to restore normal movement.
- training of new muscle action.
- Improved venous and lymphatic drainage as oedema and gravitational ulcer by pumping action of muscle contraction and relaxation.
- Prevention and loosening of adhesion.
- Painful knee syndrome.
Contraindication[edit | edit source]
- certain dermatological condition as psoriasis,tinea and eczema.
- Loss of sensation
- Cardiac pacemakers
Practical Guidelines[edit | edit source]
- The patient is positioned so that the part to be treated is comfortably supported with the muscles to be stimulated in a shortened position although this may be modified with movement produced e.g slight knee flexion allowing quadriceps stimulation to cause extension.
- The skin surface must be examined for any cuts or abrasions, treatment area should be washed to remove sebum and epithelial cells using hot water to lower resistance.
- Size of active electrode is chosen to considering size of treatment area.
- The electrode should be smaller than the pad to prevent the edge of the electrode being bent down on the skin.
- the pads should be soaked in warm tap water, saline or sodium bicarbonate solution before applied to the skin.
- Fixation is achieved with a rubber strap or by body weight.
- explain to the patient sensation.
- when muscle is to be stimulated the active electrode is placed over motor point and small current is applied. The current may need to be increased and then decreased as the motor point found and good contraction obtain with less current.
- when muscle group is to be stimulated the active electrode placed at end of muscle group so current spread through the whole group.
Resources[edit | edit source]
References[edit | edit source]
- Purva Nanivadekar and Shivali Kar, “Microcontroller based Rehabilitation Stimulator”, International Journal of Computer Applications 2013
- Mangala B. Satardekar and Deepak V. Bhoir “ANALYSIS AND ENHANCEMENT IN THE PERFORMANCE OF ELECTRICAL MUSCLE STIMULATOR.”