1 2 . e l e c t r O t H e r a P y t H e O ry
104
EN
WIRELESS PROFESSIONAL
12.2.2.5 compensation for the rectangular pulse
Every time stimulation needs to be produced, a rectangular pulse current is sent out, which has the same
duration as the chronaxy of the nerve structure that needs to be stimulated. Repetition of stimulation is
obtained by repeating the electrical impulse.
Whether this is with analgesic or motor stimulation electrotherapy, the stimulations correspond to a series
of stimulations set by streams of pulses.
Repeating the pulses if they are not compensated for will result in polarisation, because the electrical
mean is not zero (Fig. 7).
Electrical
Mean
≠ 0
Non-compensated series of pulses.
The electrical mean is not zero, which causes polarisation.
Fig. 7
Fig. 8
The polarised current equates to a continuous current with a value equal to the mean intensity. Applying
this kind of polarised current to the skin has the same disadvantages as a galvanic current, i.e. risk of skin
burns in all cases, and sometimes ionisation if there is metal osteosynthetic material.
To resolve the issue of polarisation, the positive wave must be compensated for by a negative wave with
the same quantity of electrical charge, i.e. the same area on the graph (Fig. 8). The electrical mean is
therefore zero, the current is completely compensated for and the risks of polarisation are eliminated.
Compensated rectangular pulse;
S1 = S2, therefore the electrical
mean is zero.
Electrical mean = 0