Three Major Types of Current Used in Electrical Stimulation (estim)

Approximately 6 minutes

There are three basic waveforms used in commercial therapeutic electrical stimulation units: direct current, alternating current, and pulsed current.

Direct Current (DC) - Galvanic

• Continuous unidirectional flow of charged particles with a duration of at least 1 second.
• One electrode is always the anode (+) and one is always the cathode (-) for the entire event.
• There is a build-up of charge since it is moving in one direction causing a strong chemical effect on the tissue under the electrode
• Most commonly used for wound care and with iontophoresis
• Iontophoresis and microcurrent are clinical examples of direct current interventions
• Note : Monophasic also refers to direct current, but it is interrupted and not continuous (i.e., pulsed), so the chemical effect is minimal

Alternating Current (AC) - Biphasic

• Uninterrupted, bidirectional flow of ions; direction changes at least once per second.
• Frequency - the rate at which the current switches direction
• Electrodes continuously alternate their polarity each cycle, therefore no build-up of charge under the electrodes
• Types of modulated AC current used on biological tissue
• Burst-modulated - known as "Russian" current
• Amplitude-modulated - known as interferential current

Pulsed Current (pulsed - AC and DC)

• Flow of charged particles stops periodically for less than 1 second before the next event
• Pulses can occur individually or in a series
• Monophasic pulses do not alternate; pulsed monophasic (travels in one direction) current allows for a charge to accumulate in biological tissue

 

 

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