Low and medium Frequency Electrotherapy - Implox

3 FROM THEORY TO PRACTICE
3.1 Introduction
Enraf-Nonius electrotherapy equipment offers a range of current types capable of selectively stimulating the nervous
system with the aim of reducing pain, restoring the autonomic balance or stimulating the musculature. This chapter
describes the diadynamic current types, the 2-5 current and alternating currents (interferential and TENS currents).
These various forms of low-and medium-frequency electrotherapy are dealt with in one chapter because, insofar as
the aim is pain reduction or restoration of the autonomic balance, there are many similarities in the range of
indications, the method of application and the electrophysiological effects.
3.2 Diadynamic current types
3.2.1 Description of current types
Bernard uses the term ‘diadynamic current’ to refer to a monophase (MF – Monophasé Fixe) or double-phase (DF –
Diphasé Fixe) rectified alternating current, with a frequency which is derived directly from the mains supply, resulting
in sinusoidal pulses with a duration of 10 ms. This phase time of 10 ms will mainly depolarize thick fibres. Stimulation
of thin fibres as well can only be obtained at higher current amplitudes (Fig. 5).
The diadynamic current types have won a significant position in the history of (European) physiotherapy. They are
somewhat unfairly dismissed as outdated when compared with interferential currents or TENS. In fact, however, the
diadynamic currents have quite specific effects when used for pain reduction or improvement of tissue metabolism.
Enraf-Nonius (low-frequency) electrotherapy equipment is based on the four classic diadynamic current types:
• MF (Monophasé Fixe), frequency 50 Hz
• DF (Diphasé Fixe), frequency 100 Hz
• CP (Courtes Périodes), rapid alternation between one second of MF current and one second of DF current
• LP (Longues Périodes), slow alternation between six seconds of MF current and a six-second DF phase. In the
DF phase the intervals between the MF pulses are filled with additional pulses which gradually increase in
amplitude to that of the MF pulses, resulting in a DF current, after which the amplitude of the additional pulses
decreases again to zero and the MF current continues for a further six seconds. The whole duration of the DF
phase, including increase and decrease (ramp up and ramp down), is six seconds.
DF double-phase rectified alternating current.
MF monophase rectified alternating current.
LP Slow alternation between DF and MF.
CP rapid alternation between DF and MF.
Fig 7.
Current types.
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