The effect of IFT depends upon
· Intensity of current
· Electrode placement
· Localization of the lesion
100-150Hz constant or 90-100Hz rhythmic
These frequencies are useful for pain relief, IFT acts on large myelinated fibers in the dorsal horn, blocking off small pain fibers. The higher frequencies have a triggering effect on the endogenous opiates in the mid-brain which inhibit pain.
0-10Hz rhythmic or 10- 50Hz rhthymic
These frequencies are useful for muscle stimulation. They produce stimulation of deep, normally innervated muscle tissue with little sensory stimulation. As the frequency increases the contraction changes from a twitch to a tetanic contraction.
The range of frequencies produces vasodilatation. This is stimulation and relaxation of vessel walls, giving a sinusoidal effect.
Intensity of current
The current is increased until the patient feels tingling. As accommodation occurs the intensity is increased to the point of muscle stimulation. The duration of treatment varies between 10 - 20 minutes.
The patient is positioned comfortably and the skin is prepared for the treatment. It is cleaned and in case of any skin lesion the area is insulated with petroleum jelly. Vacuum electrodes or pad electrodes are positioned such that the site for the treatment is accurately located and the two pairs of electrodes are positioned so that the crossing point of the two currents is over or within the lesion.