What are Faradic Principles?

The Winks Greene Transeva is based on Faradic principles, therefore an explanation is necessary. Founded by Michael Faraday, faradism is based on the application of percutaneous stimulation through interrupted direct current (DC) (Scott, 2002). Since the DC is interrupted it acts like an alternating current (AC) (Low & Reed, 2000). The properties of faradic pulses are:

·         Pulse duration of 0.1-1.0 ms

·         Frequency between 30 and 100 Hz

·         Can be uniphasic or biphasic (Low & Reed, 2000)

·         Usually asymmetrical in nature (Figure 3)

o   Positive portion has a short duration and a high amplitude

o   Negative portion has a long duration and low amplitude (Knight & Draper, 2008)

Figure 3: An example of a faradic waveform

Even though the Winks Greene Transeva is based on faradic principles, the information regarding the specifics of the machine is minimal (Products, 2002). On the maufacturer’s website it states that the Winks Greene Transeva has:

·         Pulse duration of 0.5-1.5 seconds

·         Intensity of 10 to 390 Volts (Products, 2002)

With the transeva able to reach 390 Volts and a skin resistance of as low as 1000 Ohms if the skin is moist or broken; according to Ohms law (V=IR), the current applied to the skin is 390 mA (U.S. Department of Health and Human Services, 1998). With the use of our calculations, there is potential to exceed the sensory current for humans (5mA) and may cause tissue damage and ventricular fibrillation (fibrillation threshold 300-500 mA) (Ferris, 2005). This suggests that the transeva may have safety concerns.

With a pulse duration more than 1000 times the duration of conventional faradism. Is the Winks Greene Transeva truly based on faradic principles?

No other specifications regarding the transeva have been acknowledged on the manufacturer’s website (Products, 2002). Without further information, the way in which the Winks Greene Transeva works is unable to be determined. Furthermore, there is no evidence showing Winks Greene Transeva has safety issues, despite having no information to prove otherwise. 

Today, faradism is not a major component of therapeutic electrical stimulation in clinical practice. There are other types of electrical stimulation, transcutaneous electrical nerve stimulation (TENS), which have been proven to be safe and TGA approved (Jones & Johnson, 2009).

References

Jones, I & Johnson, M. (2009). Transcutaneous Electrical Nerve Stimulation. Continuing

Education in Anaesthesia, Critical Care & Plan, 9(4), 130-135. doi:
10.1093/biaceaccp/mkp021

Ferris, C. (2005). Safety. In J. Whitaker (2nd ed.), The Electronics Handbook (pp. 2317

2342). Boca Raton, USA: CRC Press.

Knight, K. L., & Draper, D. O. (2008). Therapeutic Modalities: The Art & Science. Baltimore,
USA: Lippincott Williams & Wilkins.

Low, J., & Reed, A. (2000). Electrotherapy Explained: Principles & Practice (3rd ed.).

Oxford, UK: Butterworth Heinemann.

Scott, O. (2002). Sensory and Motor Nerve Activation. In S. Kitchen, Electrotherapy:

Evidence-Based Practice (pp. 57-73). Edinburgh, UK: Churchill Livingstone.

U.S. Department of Health and Human Services. (1998). Worker Deaths By Electrocution

(NIOSH Publication No. 98-131). Atlanta, USA: Casini, V.

Winks Greene Transeva: Products. (2002). Retrieved March 26, 2012, from

http://www.winksgreenetranseva.com/Products/products.html