Electrical Stimulation and TENS

What are some contraindications for NMES and TENS?

Pacemaker or implanted defibrillator, unstable arrhythmia, over a thrombosis, pregnancy (over trunk), over recent tendon repair or tear

What are some precautions for NMES and TENS?

Cardiac disease, impaired sensation, malignancy, or open wounds

What is a direct current (DC)?

A continuous stream of charged particles in one direction

When would you use direct current?

Used with Iontophoresis and stimulating contractions in denervated muscles

What is alternating current (AC)?

Continuous flow of charged particles in two directions (flowing back and forth)

When should you use alternating current?

For pain management and muscle contraction

What is a pulsed current?

Interrupted flow of charged particles, pulses with periods of no current flow

When should you use pulsed currents?

Pain control, tissue healing, or muscle contraction

What is monophasic pulsed current and when should you use it?

A pulsed current that flows in one direction only

For tissue healing and edema management

What is biphasic pulsed current and when should you use it?

Pulses that go back and forth, can be symmetrical or asymmetrical

For muscle contractions and modulates pain

Most commonly used setting

What is an interferential current?

Uses 4 electrodes to produce two slightly different AC frequencies that meet in the middle and target that middle spot (like an X)

More comfortable and targets deeper tissue

What frequency should an interferential current be set to?

1,000-10,000 Hz

What is a premodulated current?

Sequentially increases and decreases the current amplitude with a single circuit, not as deep as IFC, good for pain management, edema, and slow muscle contractions

2 electrodes total

What frequency should a premodulated current be set to?

1,000-10,000 Hz

What is a Russian protocol current?

Used for muscle re-education, 10 ms-long bursts with 50 bursts per second

What frequency does a Russian protocol current have to be used at?

2,500 Hz

What is a phase?

The period when a current flows in one direction

What is phase duration?

How long a phase lasts (time the phase occurs for) in microseconds

What is a pulse?

The period when electrical current flows in any direction (biphasic)

What is a pulse duration?

How long a pulse lasts from start of first phase to end of the last phase

What is frequency?

The number of cycles or pulses that occur in one second, measured in Hz or pulses per second (pps)

What is amplitude?

the magnitude or strength of the current flow (measured in amps or volts)

What is the interpulse interval?

The time no pulse or phase is occurring

How does TENS modulate pain?

Activates non-nociceptor A-beta fibers to stop the transmission of pain signals (tricks the brain)

Can also release the body’s opioid (endorphins) that are the body’s natural Tylenol

How long can low-rate TENS help release endorphins in the body for?

4-5 hours post treatment

When do you use neuromuscular electrical stimulation (NMES)?

Use in innervated muscles, with AC or PC current (Russian or pulsed biphasic)

When do you use electrical muscle stimulation (EMS)?

Use on denervated muscles with DC current

What type of muscle fiber is activated with physiologically initiated contraction?

Slow twitch type 1 fibers first, then type 2 fibers

What type of muscle fiber is activated with electrically stimulated contraction?

Fast twitch type 2 first, then type 1 fibers

When should you use a biphasic frequency of < 30 pps?

To stimulate motor nerves and for smaller muscles

When should you use a biphasic frequency of 35-50 pps? *Recommended frequency

Twitches are closer together and form a smoother contraction for larger muscles

When should you use a biphasic frequency of 50-80 pps?

For stronger contractions and can increase muscle strengthening and increase fatigue

What is galvanotaxis?

Movement of cells in response to the electrical fields. Use a negative electrode to promote healing of inflamed or infected wounds (cathode). Use positive electrode to promote healing of wounds w/o inflammation (anode)