Electrotherapeutic Basics Flashcards

1
Q

What 3 things must be present to have a current

A
  1. A source of electrons
  2. A conductor of the electrons
  3. A driving force of electrons
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2
Q

What are atoms that possess charge known as

A

Ions

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3
Q

Where do ions move from and to

A

From areas of high concentrations to areas of low concentrations

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4
Q

What is the net movement of charged particles along a conductor

A

Current

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5
Q

What is the amount of potential (electrical) difference between two points ([ions] or electrons) in an electrical field

A

Electromotive force (EMF)

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6
Q

What does the electromotive force do

A

Drives the charged particles that are measured in volts

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7
Q

What size electromotive does the commercial current flowing from a wall outlet produce (2)

A
  1. 110-115 V

2. 220-240 V

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8
Q

True or False:

Electrotherapeutic modalities modify voltage for specific therapeutic purposes

A

True

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9
Q

True or False:
In the human system the electric stimulator generates a voltage to overcome resistance allowing a current to flow along the path of least resistance

A

True

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10
Q

What makes an electrotherapeutic modality a low voltage generator

A

Produces a voltage less than 150 V

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11
Q

What makes an electrotherapeutic modality a high voltage generator

A

Produces a voltage greater than 150 V

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12
Q

What is a coulomb (C)

A

The measure of electric charge equal to 6.25*10^18 electrons

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13
Q

What is an ampere (A)

A

The measure of current flow equal to 1 C per second

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14
Q

What is an Ohm (omega)

A

Measure of resistance to current flow

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15
Q

What is voltage (V)

A

Measure of the potential difference or EMF required to move 1 A of current across 1 Ohm of resistance

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16
Q

What is resistance (Ohms)

A

The ability of a medium to resist the flow of electrons through direct current

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17
Q

What is inductance

A

Opposition to electron flow created by electromagnetic eddy currents generated when current is passed through a wire

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18
Q

What is capacitance

A

Ability of a material to store an electrical charge

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19
Q

What is impedance

A

Resistance + inductance + capacitance

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20
Q

What are conductors

A

Materials that offer little resistance and allow current to flow easily

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21
Q

What are insulators

A

Materials that offer high resistance to current flow

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22
Q

What are semiconductors

A

Materials that offer neither high nor low resistance to current flow

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23
Q

What is the pump of water flow equal to in electron flow

A

Volts

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24
Q

What is the gallons of water/min equal to in electron flow

A

Ampere

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25
Q

What is the length and diameter of the pipe equal to in electron flow

A

Resistance

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26
Q

Energy created by water flowing is dependent on what (2)

A
  1. Pressure in the pipe

2. # of gallons flowing per unit of time

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27
Q

What is electrical power measured in

A

Watts

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28
Q

What do watts equal

A

Volts*amps

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29
Q

What does power equal

A

EMFcurrent (VI)

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30
Q

What is 1 watt equal to

A

The power needed to move one ampere of current with a force of one volt

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31
Q

What is Ohm’s Law

A

The amount of electromotive force in a circuit is equal to the current intensity multipled by the resistance

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32
Q

What is the equation of Ohm’s Law

A

V=I*R

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33
Q

What does increasing the resistance do the the voltage to move current

A

Increases the voltage

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34
Q

What is a circuit that is in series

A

When the same current flows through each resister

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35
Q

What does total resistance equal in a circuit in series

A

Rt=R1+R2+…

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36
Q

What is a circuit that is in parallel

A

When current flowing through a circuit has multiple pathways to follow through or around each resister

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37
Q

What does total resistance equal in a circuit in parallel

A

1/Rt=1/R1+1/R2+…

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38
Q

What are the 3 basic electrotherapeutic currents

A
  1. Direct (DC)
  2. Alternating (AC)
  3. Pulsatile or pulsed
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39
Q

What are the 3 types of direct/galvanic/monophasic current

A
  1. Continuous
  2. Reversed DC current
  3. Interrupted DC current
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40
Q

What is continuous direct current

A

Unidirectional flow of electrical charges for at least one second

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41
Q

What is reversed DC current

A

Unidirectional flow of electrical charges for at least one second that then changes polarity

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42
Q

What is interrupted DC current

A

Unidirectional flow of electrical charges for at least on second that then stops for at least on second then resumes

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43
Q

What is direct current generally used for (3)

A
  1. Iontophoresis
  2. Stimulating denervated muscle directly
  3. Stimulate wound healing
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44
Q

What is alternating/faradic/biphasic current

A

A continuous bidirectional flow of charged particles where each cycle duration occurs in less than one second with equal ion flow in each direction

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45
Q

What does equal ion flow in each direction cause during AC current

A

No net charge to be formed

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46
Q

What does the wavelength equal in AC current

A

One cycle

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47
Q

True or False:

In AC current wavelength and frequency are inversely related

A

True

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48
Q

What is AC current generally used for (4)

A
  1. Muscle strengthening
  2. Muscle re-education
  3. Pain modulation
  4. Functional training
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49
Q

What is pulsatile/pulsed current

A

Unidirectional flow of electrical current that lasts less than one second and stops for a finite period before the next pulse

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50
Q

How long is the finite amount of time that pulsed current stops for

A

Usually 5-999 milliseconds

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51
Q

What is a dumbed down way to explain pulsed current

A

Electric current delivered discontinuously separated by a finite period of time

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52
Q

What are the 2 types of pulsed currents

A
  1. Monophasic pulsed current

2. Biphasic pulsed current

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53
Q

What are the 2 types of biphasic pulsed current

A
  1. Symmetric

2. Asymmetric

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54
Q

What are the 2 types of asymmetric biphasic current

A
  1. Balanced

2. Unbalanced

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55
Q

What makes the asymmetric biphasic current balanced and unbalanced

A

Balanced: The area under the wave is the same (so same charge) for both waves but different length of time
Unbalanced: The area under the wave is different (so different charge) but the length of time is the same

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56
Q

Does balanced or unbalanced asymmetric biphasic current result in the build up of current on one side

A

Unbalanced

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57
Q

What is the waveform

A

The shape of the current intensity vs. time graph

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58
Q

What are the possible number of phases (4)

A
  1. Monophasic
  2. Biphasic
  3. Triphasic
  4. Polyphasic
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59
Q

what are the possible symmetries of phases (2)

A
  1. Symmetry

2. Asymmetry

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60
Q

What are the possible balances of charge (2)

A
  1. Balanced

2. Unbalanced

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61
Q

What are the possible waveforms or phase shapes (5)

A
  1. Rectangular
  2. Square
  3. Triangular
  4. Saw tooth
  5. Sinusoidal
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62
Q

What are the amplitude dependent characteristics (4)

A
  1. Peak amplitude
  2. Peak to peak amplitude
  3. Root mean square amplitude
  4. Average amplitude
63
Q

What is the peak amplitude

A

The maximum current reached for a single phase

64
Q

What is the peak to peak amplitude

A

The maximum current measured from the peak of the first phase to the peak of the second phase

65
Q

What is the root mean square amplitude

A

The most common mathematical method of defining the effective voltage or current of an AC wave

66
Q

For a sine wave what is the RMS compared to the peak value and peak to peak value

A

Peak value: 0.707 times

Peak to peak value: 0.345 times

67
Q

What is the average amplitude

A

The mean voltage under the sine wave curve

68
Q

What are the time dependent characteristics (8)

A
  1. Phase duration
  2. Pulse duration
  3. Rise time
  4. Decay time
  5. Interpulse interval
  6. Intrapulse interval
  7. Period
  8. Frequency
69
Q

What is the phase duration

A

Time from beginning of a phase to the end of a phase

70
Q

What is the pulse duration

A

Time from beginning of a pulse to the end of a pulse

71
Q

What is the rise time

A

Time required from the beginning of a phase to the peak of the phase

72
Q

What is the decay time

A

Time from the peak of the phase to the end of the phase

73
Q

What is the interpulse interval

A

Time from the end of one pulse to the beginning of the next pulse

74
Q

What is the intrapulse interval

A

Time from the end of one phase to the beginning of the next phase

75
Q

What is the period

A

The time to complete one pulse

76
Q

What is the frequency

A

1/period

77
Q

What are the characteristics of a series of pulses (3)

A
  1. Interpulse interval
  2. Frequency
  3. Current modulation
78
Q

What are the ways to modulate current (5)

A
  1. Amplitude modulation
  2. Pulse duration modulation
  3. Frequency modulation
  4. Ramp modulation
  5. Timing modulation
79
Q

What is ramp modulation

A

How much time it takes to get to the peak of the individual phase

80
Q

What is timing modulation

A

Using bursts to modulate period of on time (ask Dr. Stachura about this)

81
Q

What is a burst

A

A series of pulses flowing for a finite period of time followed by a period of no current flow

82
Q

What is burst duration

A

The length of time from the beginning of the burst to the end expressed in milliseconds

83
Q

What is the interburst interval

A

Time from the end of one burst to the beginning of the next burst

84
Q

What is the burst frequency

A

The number of burst per unit of time

85
Q

What are the 3 types of electrode systems

A
  1. Carbon rubber
  2. Carbon rubber with conducting gel
  3. Vinyl covered metal plate
86
Q

What are the electrode considerations for current density (2)

A
  1. Depends upon size of electrodes

2. Depends upon electrode placemetn

87
Q

Does a smaller electrode have a smaller or higher current density

A

Higher current density

88
Q

Do electrodes placed close together have higher current density superficially or deeper in tissues

A

Superficially

89
Q

Do electrodes placed farther apart have high current density superficially or deeper in tissues

A

Deeper in tissues

90
Q

What are the 3 ways to place electrodes

A
  1. Monopolar
  2. Bipolar
  3. Quadrapolar
91
Q

What are the 2 types of quadrapolar electrode placement

A
  1. Intersecting

2. Non-intersecting

92
Q

What is the purpose of tap key electrode (2)

A
  1. Identify motor points

2. Stimulate small muscles

93
Q

Who first introduced interferential current (IFC)

A

Ho Nemec in 1950

94
Q

When did IFC come to North America

A

1980s

95
Q

What is IFC

A

A medium frequency current that produces unmodulated sinusoidal waves of similar amplitude that cross

96
Q

What do the 2 different carrier frequencies do

A

Interfere with each other to generate an amplitude modulated by beat frequency

97
Q

What is the beat frequency

A

The net difference between the two superimposed frequencies and the stimulation frequency of the waveform

98
Q

What is interference

A

When the 2 waves are brought into the same location and the amplitudes combine and are increased or summative

99
Q

What are the 2 types of interference

A
  1. Constructive

2. Destructive

100
Q

What is constructive interference

A

Two waves produced in phase or originate at the same time and the amplitudes are combined with a resulting increased amplitude

101
Q

What is destructive interference

A

Two waves produced out of phase or originate at different times and the amplitudes combine with a resulting decreased amplitude

102
Q

What happens if the waves are perfectly out of phase

A

The amplitudes will cancel each other with a resultant amplitude of 0

103
Q

What is waveforms that have two different frequencies but combine at the same location produce a beat effect

A

Interference

104
Q

What is the blending of the waves resulting in both constructive and destructive interference called

A

Heterodyne

105
Q

What is the heterodyne effect seen as

A

The rising and falling waveform

106
Q

True or False:

The beats correspond to the beat frequency and is the stimulation frequency of the waveform

A

True

107
Q

What is the beat frequency

A

The difference between the two original frequencies

108
Q

What is stimulating current pattern

A

When electrodes are placed in a square pattern an electric field is produced that looks like a four petal flower

109
Q

Where does the maximum interference occur in IFC

A

The center

110
Q

What are the types of IFC (4)

A
  1. Constant (bipolar)
  2. Variable (quadripolar)
  3. Scanning (quadripolar with vector scanning)
  4. Stereodynamic
111
Q

What is constant IFC

A

Both carrier frequencies are fixed

112
Q

What is variable/quadripolar IFC

A

One carrier frequency is fixed while the other varies in frequency creating a variable or sweep frequency

113
Q

What is variable/quadripolar IFC used for

A

Minimize patient accommodation to the current

114
Q

What is scanning IFC

A

The ability to move the entire petal of stimulation so as to effect a larger treatment area

115
Q

What is stereodynamic IFC

A

Three distinct circuits that blend and create a distinct wave

116
Q

Who developed the first high voltage pulsed current (HVPC)

A

Haislip with Bell laboratories in 1940s

117
Q

Who did the first human study with HVPC

A

Thurman et al in 1971

118
Q

What did Lehman do in 1974

A

Called HVPC high voltage electro galvanic stimulator

119
Q

What does the term galvanic erroneous for

A

That current was not direct or continuous current but rater pulsed

120
Q

What is HVPC

A

Twin peaked, monophasic, pulsed current that is driven by characteristically high EMF from 150-500 volts

121
Q

What is a twin peak monophasic pulse

A

Pair of monophasic spike like waveforms with an almost instantaneous rise followed by exponential decline

122
Q

What is the pulse duration of HVPC

A

Short from 100-200 usec

123
Q

True or False:

HVPC are generally fixed by the manufacturer

A

True

124
Q

True or False:

Some HVPC allow for adjustment of interspike interval

A

True

125
Q

What is the pulse frequency of HVPC

A

1-200 pps

126
Q

What does capacitance equal

A

Charge/voltage

127
Q

Do high voltage sources have more or less capacitance

A

Less

128
Q

Do low capacitance sources have high or low tissue impedance

A

Low tissue impedance

129
Q

Are low tissue impedances more or less comfortable

A

More comfortable

130
Q

True or False:
For HVPC there is a need for high voltage output due to extreme shortness of pulse duration at it peak in keeping with classic strength duration curve

A

True

131
Q

If your pulse duration is short what is your current amplitude for HVPC

A

Higher current amplitude

132
Q

What does the versatility or high voltage output and monophasic pulsed waveform allow for (2)

A
  1. Electric nerve/muscle stimulation

2. Wound healing

133
Q

Who created Russian Current

A

Yakov Kots in 1977

134
Q

How does Russian Current effect human muscle contraction

A

It can generate up to 30% more force then that generated by a MVC

135
Q

Is the application of Russian Current painful or painless

A

Painless

136
Q

Russian Current can cause what to happen in short term training

A

Produce lasting gains in muscle strength of up to 40% in healthy subjects

137
Q

When was the first Russian Current stimulator produced in the US

A

1980

138
Q

What is the clinical importance of Russian Current

A

You possibly train individuals without the need of voluntary contractions

139
Q

True or False:

Russian Current is a time modification of continuous sinewave having carrier frequency of 2500 pps

A

True

140
Q

How long is Russian Current burst modulated fixed for

A

10 msec periods

141
Q

What is the fixed interpulse interval (IPI) for Russian Current

A

10 msec

142
Q

What is the burst frequency of Russian Current

A

50 bursts per second (bps)

143
Q

What is the carrier frequency of Russian Current

A

2500 pps

144
Q

What is the burst duration of Russian Current

A

10 msec

145
Q

What is the interpulse interval of Russian Current

A

10 msec

146
Q

What determines the magnitude of effect

A

The total # of bursts/sec

147
Q

What is each burst at the nerve muscle membrane treated as

A

A single pulse

148
Q

What does repeated delivery of these bursts during Russian current lead to

A

Motor nerve depolarization and tetanic contraction

149
Q

What are the physiologic effects of Russian Current (3)

A
  1. Depolarize both motor and sensory neurons simultaneously
  2. Muscle contraction will be painless
  3. Higher current amplitudes can be used
150
Q

What will higher current amplitudes stimulate

A

Deeper motor neurons

151
Q

How are motor units activated with Russian Current

A

Preferential activation of type II motor units

152
Q

When is motor unit recruitment deficient with Russian Current

A

During maximum voluntary muscle contraction

153
Q

True or False:
Russian Current is unable to recruit large #s of large type II fast twitch motor units or get them to fire fast enough to develop max muscle force

A

True (Dr. Stachura get cleared up)

154
Q

With Russian Current what do higher current amplitudes that are painless stimulate

A

Larger pool of type II motor units