1st Electromagnetic Spectrum, Physiotherapy Modalities, and Electrical Principles

What is frequency?

Number of cycles or pulses per second

What unit measures frequency?

Hertz (Hz)

What is wavelength?

One complete cycle of current

What is the relationship between frequency and wavelength?

Inverse relationship

As wavelength decreases what happens to frequency?

Frequency increases

As wavelength increases what happens to frequency?

Frequency decreases

What is physiotherapy?

Use of physical agents for therapeutic purposes

Examples of physiotherapy agents?

Temperature, electricity, light, sound, vibration, forces, water

What is low frequency range?

0-1,000 Hz

What is middle frequency range?

1000-100000 Hz

What is high frequency range?

100,000 Hz - 1x10₁₀ Hz

What is ultra high frequency?

Greater than 1x10₁₀ Hz +

What modalities are low frequency?

LVDC, HVDC, FWC, SWC, SQWC, TENS, MENS

What modalities are middle frequency?

IFC and Russian Current

What modalities are high frequency?

Ultrasound, SWD, MWD

What modalities are ultra high frequency?

IR and UV

Low frequency treatment depth?

Less than 1 inch

Middle frequency treatment depth?

About 1 inch

High frequency treatment depth?

About 2 inches

Ultra high frequency treatment depth?

Less than 1 inch

What is charge?

Strength

What is current?

Rate of flow

What is voltage?

Driving force

What is resistance?

Opposition to current flow

State Ohm's Law.

Current = Voltage / Resistance

Increasing voltage does what to current?

Increases current

Increasing resistance does what to current?

Decreases current

Current follows what path?

Path of least resistance

What is capacitance?

Ability to store charge and oppose changes in current flow

What two conditions are required for current flow?

Energy source and conducting pathway

A Like charges do what?

Repel

Opposite charges do what?

Attract

What is the anode?

Positive electrode

What is the cathode?

Negative electrode

What is an anion?

Negative ion

What is a cation?

Positive ion

At rest the inside of a nerve is what charge?

Positive

At rest the outside of a nerve is what charge?

Negative

What forms under the cathode?

Sodium hydroxide

Cathode effect on tissue?

Alkaline, tissue softening

What forms under the anode?

Hydrochloric acid

Anode effect on tissue?

Acidic, tissue hardening

High water content tissues have what impedance?

Low impedance

High water tissues are what?

Good conductors

Examples of good conductors?

Muscle, nerve, deeper skin layers

Examples of poor conductors?

Bone, fat, tendon, fascia

Edema causes what change in impedance?

Increases impedance

Scarring causes what change in impedance?

Increases impedance

Open wounds cause what change in impedance?

Decrease impedance

How can impedance be reduced?

Clean skin, clip hair, warm treatment area

Why is fat a problem with electrical stimulation?

It increases impedance

What does HVDC stand for?

High Voltage Direct Current

What is another name for HVDC?

High Voltage Pulsed Current

HVDC is continuous or pulsed?

Pulsed

HVDC waveform?

Twin peaked monophasic

HVDC current flow direction?

One direction

HVDC is more comfortable than LVDC because?

Short pulse duration

HVDC pulse duration?

About 100 microseconds

HVDC main uses?

Pain, edema, wound healing, muscle reeducation

Acute polarity for HVDC?

Anode

Chronic polarity for HVDC?

Cathode

Anode physiological effects?

Vasoconstriction, analgesia, edema reduction

Cathode physiological effects?

Vasodilation, circulation increase, stimulation

Pain frequency for HVDC?

80-120 Hz

Edema frequency for HVDC?

10-20 Hz

Muscle contraction frequency for HVDC?

35-50 Hz

Wound healing frequency for HVDC?

80-100 Hz

HVDC electrode setup?

Monopolar

Where is the active electrode placed?

Over the injury or wound

Smaller electrode produces what?

Stronger effect

Why is HVDC safer than LVDC?

Less chemical buildup and skin irritation

How does HVDC reduce edema?

Muscle pumping and polarity effects

Early wound healing polarity?

Anode

Later wound healing polarity?

Cathode

HVDC contraindications?

Pacemaker, pregnancy, malignancy, infection

Can HVDC contract denervated muscle?

No

What is rise time?

Time from zero to maximum amplitude

What is pad switching rate?

0, 5, or 10 seconds

What does MSI stand for in HVDC settings?

Higher acute, lower chronic

Monopolar placement is best for?

Tissue healing

What is alternating current?

Bidirectional flow of charged particles

Net polarity of AC?

Zero

AC waveforms?

Sine, Square, Faradic, Hybrid

Most common AC waveform?

Sine wave

Most comfortable AC waveform?

Sine wave

Faradic waveform produces what?

Tetanized contraction

Faradic wave appearance?

Semi sine then spike

Hybrid wave is a combination of?

Square and Faradic

Square wave narrow pulse is used for?

Acute conditions

Square wave wide pulse is used for?

Chronic conditions

Who developed IFC?

Hans Nemec

Another name for IFC?

Heterodyne wave

How many channels does IFC use?

Two

How many electrodes does IFC use?

Four

What frequencies do IFC channels produce?

Middle frequency carrier frequencies

What is the beat frequency?

Low frequency created by interference

Beat frequency is created where?

Within the body

Beat frequency formula?

Channel 2 minus Channel 1

4000 Hz and 4100 Hz create what beat frequency?

100 Hz

Beat frequency is endogenous or exogenous?

Endogenous