Electrical Stimulation

All Kinds of Choices

Stimulating Units

• Fall into one of two categories:

• Low Volt (Less than 100V)– TENS (9V battery)

• High Volt (Greater than 100V)– Pretty much everything else

Carrier Frequencies

• Low-frequency currents– 1000 pps or less (Monophasic, Biphasic)

• Medium-frequency currents– 1000 pps – 100,000 pps (IFC, Russian)

• High-frequency currents– 100,000 pps and higher (Diathermies)

Waveforms

• Monophasic

• Biphasic

• Interferential

• Pre-modulated Interferential

• Russian

• TENS

• Microcurrent

Monophasic

•Unidirectional flow of electrons

•Negative / Positive polarity

•“Twin Peaked Monophasic”

Peak Current

Pulse Duration

75 µs

Biphasic

•Positive and Negative Phases

•Symmetrical / Asymmetrical

Interferential Current

•Two channels at separate frequencies•Less skin resistance•Quadripolar Electrode Configuration

5,000 Hz

5,100 Hz

Interferential

Channel 1

Channel 2

Beat Frequency: 100 Hz

Interference Current

Ch 1

Ch 2

Ch 2

Ch 1

Pre-modulated IFC

•Bipolar electrode configuration

•“Mixing” of currents occurs inside the machine

•Less penetration than IFC

Russian

•Classical Russian Stim involves 2500 Hz carrier frequency w/ beat frequency from 1 – 100 Hz•Thought to allow more current to reach motor nerve at lower intensities•Results have never been duplicated

TENS

•“Transcutaneous Electrical Nerve Stimulation”•Primarily used for pain reduction

–Gate Control

–Endogenous-opiate release

Microcurrent

•Subsensory or very low sensory level•Very small current amperage / Very high pulse duration•Very theoretical / not much supporting research•Attempts to re-establish body’s natural electrical balance by allowing ATP supply to increase metabolic energy for healing to occur

Levels of Electrical Stimulation

• Subsensory• Sensory

– Pain Relief – Edema Control

• Motor– Pain Relief– Edema Control– Muscle Re-education

• Noxious

Subsensory

• Microcurrent

• Unable to stimulate nerve or muscle

• Variety of recommended parameters

• Generally consists of 2 – 10 minute Tx’s

Parameters

• 1st Treatment– Frequency: 30 Hz

– Intensity: 600 µA

• 2nd Treatment– Frequency: .3 Hz

– Intensity : 60 µA

• Lynn Wallace

• Pain Mode– Frequency: 30 Hz

– Intensity: 80-100 µA

• Healing Mode– Frequency: .3 Hz

– Intensity: 20-40 µA

Sensory Level Pain Relief

• Stimulation at or above sensory threshold but below motor level

• Stimulation of Aβ fibers – Gate Control Theory

• Frequency: 50 – 150 Hz• Phase Duration: Less than 100 µs

• Intensity: Comfortably strong

Sensory Level Edema Control

• Done immediately following injury to limit formation of edema

• Not widely researched but a few theories– Decreased capillary pressure and permeability

which keeps plasma and proteins from entering extracellular tissues

– Vascular spasm preventing leaking from vessels

• Waveform: Monophasic

• Frequency: 120 pps

• Phase Duration: As high as possible

• Intensity: Comfortably strong

• Monopolar electrode configuration– Negative electrodes over injured area

Motor Level Pain Control

• Best used with subacute / chronic pain

• Endogenous opiate release– Longer duration of pain relief

• Also good for trigger points

• Frequency: Low; 2-4 pps

• Phase Duration: Wide; 200-300 µs

• Intensity: Strong, twitch contractions

Motor Level Edema Control

• Muscular contractions encourage venous and lymphatic “milking” fluids from the area

• Electrodes arranged to follow primary vein exiting swollen area

• May be continuous or on / off time

• Continuous

• Frequency: 1 – 2pps(or as low as possible)

• Phase Duration:– 200 – 400 µs

• Intensity:– Strong, twitch contractions

• On / Off time

• Frequency: 25 – 50pps

• Phase Duration:– 200 – 400 µs

• Intensity:– Strong, tonic contractinons

• Duty Cycle: 50%– 5 on / 5 off

– 10 on / 10 off

Muscle Re-education

• Neuromuscular Electrical Stimulation (NMES)• Muscle re-education, reduction of spasticity, delay

of atrophy, muscle strengthening• Stronger type of current, not as comfortable as

other forms of ES• Not as effective as voluntary contractions

• Frequency: 25 – 50 pps

• Phase Duration: 200 – 400 µs

• Intensity: Strong tonic contractions

NMES Principles

• Duty Cycle– 1:5 (10 on / 50 off) Strength– 1:2 (10 on / 20 off) Endurance– 1:1 (10 on / 10 off) Fatigue

• Ramp Times– Fast ramp on: .5 – 1 sec Power– Long ramp on: 1 – 2 sec Strength– Long ramp off: 3 – 5 sec Eccentrics

Noxious Stimuli

• Causing pain to relieve pain

• Stimulation of Aδ and C fibers

• Electrode placement is variable

• Generally used as a last resort

• Longer lasting pain relief

• Frequency: 1-5 pps or 80-100 pps

• Phase Duration: 1 ms or higher

• Intensity: Noxious (painful)

Conclusion

Lots of machines, lots of choices.

Everybody is different, so don’t be afraid to try different things if things aren’t going as planned.