Electrotherapy

Question 1

Red wire

Answer 1

Positive
Should be on the distal muscle belly

Question 2

Black wire

Answer 2

Negative
Should be placed on the on the motor point of the muscle that you are trying to activate

Question 3

Electricity

Answer 3

Force created by an imbalance in the number of electrons at two points

Question 4

Electromagnetic force

Answer 4

Electrons flow in an attempt to equalize the difference in charges thus creating an electrical current

Question 5

Benefits of electrotherapeutic agents

Answer 5

Uses electricity and electromagnetic spectrum to…
- Facilitate tissue healing
- Improve muscle strength and endurance
- Decrease edema
- Modulate pain
- Decrease the inflammatory process
- Modify the healing process

Question 6

Electrical stimulation

Answer 6

Application of therapeutic electrical current device to stimulate excitable tissues with aim of producing physiological reaction for therapuetic benefits

Question 7

Types of electrotherapeutic agents

Answer 7

Electrical muscle stimulation (EMS)
- For denervated muscles (uses direct current)
Neuromuscular electrical stimulation (NMES)
- For innervated muscles (uses alternating current)
Functional electrical stimulation (FES)
Transcutaneous electrical nerve stimulation (TENS)
High-voltage galvanic stimulation for tissue and wound repair (ESTR)
High-voltage pulsed current (HVPC)
Iontophoresis (Ionto)

Question 8

Direct current (DC)

Answer 8

AKA Galvanic
Continuous unidirectional flow of electrons being either positively or negatively charged
There is always one electrode that is an anode (+) and one electrode that is always a cathode (-) for the entire time the current if flowing
Potential for chemical reactions due to build up of electrical charge from unidirectional flow
- Acidic reactions occur at anode due to oxidation
- Alkaline reactions occur at cathode
- May lead to increased risk for chemical burns or irritation
Used for iontophoresis, wound healing, and stimulation of denervated muscle
Area within geometric shape of electrical impulse represents total current the pulse contains
- Square - basic pattern
- Trapezoid
- Sawtooth
- Triangle
- Spike
- sine

Question 9

Alternating current (AC)

Answer 9

Current characterized by continuous change in direction of electron flow with a bidirectional flow
Electrodes alternate polarity between positive and negative
Can be used with Russian current, NMES, FES, TENS, and household electricity
May be pulsed if desired

Question 10

Pulsatile current (PC)

Answer 10

Electron flow is periodically interrupted
Interphase interval is the interruption in current flow between two phases

Question 11

Types of pulsatile current

Answer 11

Monophasic (unidirectional flow with A-pause pattern)
Biphasic (bidirectional flow with A-B-pause pattern)
- Symmetrical intensity of positive and negative are equal
- Balanced asymmetrical: intensity of positive and negative are equal but different shapes
- Unbalanced asymmetrical: intensity and shapes are different for positive and negative
Polyphasic (bidirectional flow with A-B-A-pause pattern)

Question 12

Stimulation of motor nerves

Answer 12

Will result in muscle activity

Question 13

Stimulation of sensory nerves

Answer 13

Will cause gentle tingling sensation to counteract pain

Question 14

Stimulation of pain nerves

Answer 14

Will cause a painful stimulus to activate the body’s built-in pain-relieving systems

Question 15

Resistance

Answer 15

Resistance to flow of particles
Fat and dry skin have high resistance
Muscle and clean and moist skin have low resistance

Question 16

Capacitance

Answer 16

Ability to store an electric charge and resist change in current flow
Higher capacitance = longer it will take before a response occurs
Nerves have the lowest capacitance
- Muscle fiber
- Muscle tissue has the highest capacitance
Must intensity with decreased pulse duration to stimulate tissues with a higher capacitance

Question 17

Action potential

Answer 17

Initiated by a stimulus above a certain intensity or threshold
Causes voltage-gated Na+ channels to open at the trigger zone
Stimulus could be a pin prick, light, heat, sound, or electrical disturbance
Action potential is conducted down the axon as the axon depolarized

Question 18

Muscle fasiculations

Answer 18

Muscle twitch

Question 19

Muscle tetany

Answer 19

Sustained contraction resulting from higher

Question 20

Muscle contraction

Answer 20

Motor neuron begins in anterior horn of spinal cord, exits through anterior root, travels to muscle fibers where it synapses and Neuromuscular junction
As action potential reaches neuromuscular junction, the electrical signal causes the muscle fiber to contract
Individual muscle fibers contract to their fullest extend and do not partially contract
Muscle contraction can be graded by
- Frequency of stimulation
- Number of motor units stimulated

Question 21

Voluntary contraction

Answer 21

Small, slow twitch, and type 1 motor nerves are recruited first and selectively
Nerve fibers fire asynchronously, with small motor units being recruited first and large motor units recruited only when muscle is required to produce increase force output
Allows for fine motor control, larger fibers recruited allowing smooth, controlled movements

Question 22

Electrically stimulated contractions

Answer 22

Larger, fast twitch, type 2 fibers are recruited first
Muscles fatigue rapidly
Limits finely controlled quality of functional movement

Question 23

In what muscle type will atrophy occur first in

Answer 23

Large, fast-twitch fibers

Question 24

Overload principle

Answer 24

Workload must be gradually increased as the body adapts so intensity is slightly above that which they would usually perform at
Achieve through increasing frequency, intensity, or time

Question 25

Electrodes

Answer 25

Allows current to flow from stimulation devices into body with little resistance
Self-adhesive or adhered by tape
Must have adequate skin contact
Variety of conductive substances are used such as gels and H20 based substances
- Gel must completely cover the electrodes
Less effective therapeutic treatment on areas of low conductivity
Skin must be clean with long hair clipped
Larger electrodes disperse current and are less specific in stimulated isolated movement
As electrode size decreases, current density increases which leads to increased perception of stimulation and greater physiologic response
If current density is excessive, it will result in discomfort, skin burns, and potential tissue damage

Question 26

Monopolar stimulation

Answer 26

Uses small active electrodes

Question 27

Bipolar stimulation

Answer 27

Uses electrodes of approximately the same size placed at each end of the muscle belly

Question 28

When should electrodes be replaced?

Answer 28

When there is a biting or stinging sensation

Question 29

Primary factors limiting therapeutic effectiveness

Answer 29

Uneven, inadequate contact
Pressure of electrodes
Poor electrical conductance

Question 30

Orientation of electrodes

Answer 30

Muscle fibers are more conductive when the current flows with the direction of the fibers and electrodes are oriented parallel in direction of muscle fibers
Distance between electrodes will influence depth and course of current
- If electrodes are close, the current will pass superficially
- Electrodes that are farther apart will penetrate deeper
Electrodes should be placed no closer than one half the diameter of the electrode

Question 31

Interferential frequency current

Answer 31

Utilizes alternating, low frequency current that has been modified and uses two medium frequency currents: one preset by equipment and one adjusted by clinician
Primarily used for pain relief, decreasing edema, increasing blood flow, and muscle stimulation

Question 32

Path that electrical current will take

Answer 32

Electrical current will take the path of least resistance even it has to travel a longer distance
Will flow from high electron concentration to less concentration