Vice President of Sales and Marketing, BioMedical Life Systems, Inc.
What are the parts of the T.E.N.S. unit waveform and what do they mean to me? It's not a stupid question, and you won't find the answer in most of the product instruction manuals. However, I am here to tell you that if you are a clinician reading this and you don't know what the "P.R." setting on the T.E.N.S. unit means to your patient, you're not alone!
Let's start with the basics.
What makes a "T.E.N.S. unit” a T.E.N.S. unit is the asymmetrical biphasic square waveform that is being output from the unit via the electrodes that are attached to the skin.
There are three parts to a T.E.N.S. unit waveform.
1. Pulse Rate
Pulse Rate is also known as any and all of the following: Hertz (Hz), Frequency, P.R. or Pulses Per Second (pps).
To simplify this, I like to think of it as "Pulses Per Second." The Frequency of the T.E.N.S. waveform can range from approximately 1-250Hz depending upon the model. Pulse Rate is important because different frequency settings target different nerve groups and the setting will determine if the "Gate Theory" or "Endorphin Theory" of T.E.N.S. will be used.
2. Pulse Width
Pulse Width is also known as any and all of the following: Microseconds (uS). PW, and Pulse Duration.
To simplify this, the pulse width is how wide each pulse is. It's measured in extremely small intervals called microseconds. The Pulse Width on T.E.N.S. devices usually range from 1-250uS. Generally speaking, the higher the pulse width, the more "aggressive" the stimulation feels, and eventually, if the pulse width is set high enough, it will usually elicit a muscle contraction, which is typically not the desired result with a T.E.N.S. However, if the pulse width is too low, the patient may not perceive the stimulation.
Amplitude is also known as any and all of the following: Intensity or Milliamps (mA).
To simplify this, the amplitude is what you feel when you "turn the unit up". It's what causes the "buzzing" sensation of the T.E.N.S. to go higher or lower. Portable T.E.N.S. can range from approximately 0-100 mA. This is often set to patient comfort levels.