Transcutaneous Electrical Nerve Stimulation (TENS)

Machine Settings

1. Frequency/Pulse Rate: The number of electrical pulses delivered per second (measured in Hertz/Hz)

• Determines how often the nerve fibers are stimulated

• Usually set between 2-10 Hz for opioid mechanism

• Usually set between 80-130 Hz for gate mechanism of pain reduction

• One setting for pain reduction is not inherently "better" than the other - may require several trials with a patient and gathering their feedback to find what setting works best for managing their symptoms 

• Some machines offer a "burst setting" where both frequencies can be delivered at the same time, although some patients may find this uncomfortable but it is worth trying as it can be more effective

2. Pulse duration: How long each single pulse from the frequency/pulse rate lasts (measured in microseconds/μs)

• General rule is to use 200 microseconds

  • Is effective and usually more comfortable for patients

3. Intensity (amplitude): The strength of the electrical currents being delivered into the treatment area (which combine to form the therapeutic current - measured in milliamps/mA)

• Controls how much of the current goes into the body 

• Is the only setting adjusted based on patient feedback

• Should be slowly increased until the patient feels a strong but comfortable tingling sensation

• Think of this as the volume in music

4. Current pattern/mode of delivery: How the electrical pulses are patterned or varied

• It influences how the nerves respond to stimulation and helps prevent nerve adaptation (accommodation)

• Most common type of pattern is "traditional" setting

• Other types are burst, brief intense, and acupuncture settings

• Traditional: Helps with pain relief in the moment (while TENS is on) and shortly afterward

  •  Uses a high frequency (80-130 Hz), high pulse width (200 microseconds), and having the intensity at a strong but comfortable feeling 

  • Duration typically 30 minutes

• Acupuncture: Helps with longer carry-over with pain relief once disconnected from TENS through utilizing the opioid mechanism

  •  Uses a lower frequency (2-10 Hz), longer pulses (200-250 microseconds), and having the intensity at a strong and slightly uncomfortable feeling

  • Duration typically 30 minutes

• Brief intense: Helps with rapid pain relief 

  • Uses a high frequency (80-130 Hz), high pulse width (200 microseconds), and having the intensity at the most a patient can tolerate

  • Duration typically 15-30 minutes

• Burst: Helps with pain relief through causing gate mechanism and opioid mechanisms simultaneously

  • Is essentially the traditional setting but the flow is interrupted so the frequency is sent out in bursts (usually 2-3 bursts per second), which creates an additional lower frequency inducing the opioid mechanism

  • Duration typically 30 minutes

5. Duration: The amount of time the TENS machine is on

• Treatment time in a clinic is usually at the end of a session for 10-15 minutes

• Because using TENS for long periods in the clinic isn’t always practical, it’s helpful to advocate for a home unit that insurance might cover

• It is recommended patients use their TENS unit at home for longer durations - 30 minutes at a time and can be used multiple times a day

Quiz Questions

1. How does TENS differ from IFC in terms of current delivery?

A. TENS uses high-frequency intersecting currents

B. TENS uses two medium-frequency currents that cross in the tissue

C. TENS uses a single low-frequency current

D. TENS uses ultrasound waves to stimulate tissues

2. Why might TENS feel more uncomfortable than IFC for some patients?

A. It uses suction electrodes

B. Low-frequency currents are more difficult to travel through the skin

C. It uses higher voltage settings

D. It penetrates the bone directly

3. Which of the following frequencies would best stimulate the opioid mechanism of pain relief?

A. 80–130 Hz

B. 50–70 Hz

C. 2–10 Hz

D. 140–180 Hz

4. Which TENS mode is designed to provide longer carry-over pain relief once the unit is removed?

A. Traditional

B. Acupuncture

C. Brief intense

D. Burst

5. What is the recommended pulse duration for most TENS settings?

A. 100 microseconds

B. 500 microseconds

C. 200 microseconds

D. 50 microseconds

6. Which TENS mode delivers both gate control and opioid mechanisms by interrupting flow in bursts?

A. Acupuncture

B. Burst

C. Brief intense

D. Traditional