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Flashcards in Electrotherapeutic Basics Deck (154):
1

What 3 things must be present to have a current

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

2

What are atoms that possess charge known as

Ions

3

Where do ions move from and to

From areas of high concentrations to areas of low concentrations

4

What is the net movement of charged particles along a conductor

Current

5

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

Electromotive force (EMF)

6

What does the electromotive force do

Drives the charged particles that are measured in volts

7

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

1. 110-115 V
2. 220-240 V

8

True or False:
Electrotherapeutic modalities modify voltage for specific therapeutic purposes

True

9

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

True

10

What makes an electrotherapeutic modality a low voltage generator

Produces a voltage less than 150 V

11

What makes an electrotherapeutic modality a high voltage generator

Produces a voltage greater than 150 V

12

What is a coulomb (C)

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

13

What is an ampere (A)

The measure of current flow equal to 1 C per second

14

What is an Ohm (omega)

Measure of resistance to current flow

15

What is voltage (V)

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

16

What is resistance (Ohms)

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

17

What is inductance

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

18

What is capacitance

Ability of a material to store an electrical charge

19

What is impedance

Resistance + inductance + capacitance

20

What are conductors

Materials that offer little resistance and allow current to flow easily

21

What are insulators

Materials that offer high resistance to current flow

22

What are semiconductors

Materials that offer neither high nor low resistance to current flow

23

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

Volts

24

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

Ampere

25

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

Resistance

26

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

1. Pressure in the pipe
2. # of gallons flowing per unit of time

27

What is electrical power measured in

Watts

28

What do watts equal

Volts*amps

29

What does power equal

EMF*current (V*I)

30

What is 1 watt equal to

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

31

What is Ohm's Law

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

32

What is the equation of Ohm's Law

V=I*R

33

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

Increases the voltage

34

What is a circuit that is in series

When the same current flows through each resister

35

What does total resistance equal in a circuit in series

Rt=R1+R2+...

36

What is a circuit that is in parallel

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

37

What does total resistance equal in a circuit in parallel

1/Rt=1/R1+1/R2+...

38

What are the 3 basic electrotherapeutic currents

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

39

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

1. Continuous
2. Reversed DC current
3. Interrupted DC current

40

What is continuous direct current

Unidirectional flow of electrical charges for at least one second

41

What is reversed DC current

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

42

What is interrupted DC current

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

43

What is direct current generally used for (3)

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

44

What is alternating/faradic/biphasic current

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

45

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

No net charge to be formed

46

What does the wavelength equal in AC current

One cycle

47

True or False:
In AC current wavelength and frequency are inversely related

True

48

What is AC current generally used for (4)

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

49

What is pulsatile/pulsed current

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

50

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

Usually 5-999 milliseconds

51

What is a dumbed down way to explain pulsed current

Electric current delivered discontinuously separated by a finite period of time

52

What are the 2 types of pulsed currents

1. Monophasic pulsed current
2. Biphasic pulsed current

53

What are the 2 types of biphasic pulsed current

1. Symmetric
2. Asymmetric

54

What are the 2 types of asymmetric biphasic current

1. Balanced
2. Unbalanced

55

What makes the asymmetric biphasic current balanced and unbalanced

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

56

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

Unbalanced

57

What is the waveform

The shape of the current intensity vs. time graph

58

What are the possible number of phases (4)

1. Monophasic
2. Biphasic
3. Triphasic
4. Polyphasic

59

what are the possible symmetries of phases (2)

1. Symmetry
2. Asymmetry

60

What are the possible balances of charge (2)

1. Balanced
2. Unbalanced

61

What are the possible waveforms or phase shapes (5)

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

62

What are the amplitude dependent characteristics (4)

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

63

What is the peak amplitude

The maximum current reached for a single phase

64

What is the peak to peak amplitude

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

65

What is the root mean square amplitude

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

66

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

Peak value: 0.707 times
Peak to peak value: 0.345 times

67

What is the average amplitude

The mean voltage under the sine wave curve

68

What are the time dependent characteristics (8)

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

69

What is the phase duration

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

70

What is the pulse duration

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

71

What is the rise time

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

72

What is the decay time

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

73

What is the interpulse interval

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

74

What is the intrapulse interval

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

75

What is the period

The time to complete one pulse

76

What is the frequency

1/period

77

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

1. Interpulse interval
2. Frequency
3. Current modulation

78

What are the ways to modulate current (5)

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

79

What is ramp modulation

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

80

What is timing modulation

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

81

What is a burst

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

82

What is burst duration

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

83

What is the interburst interval

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

84

What is the burst frequency

The number of burst per unit of time

85

What are the 3 types of electrode systems

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

86

What are the electrode considerations for current density (2)

1. Depends upon size of electrodes
2. Depends upon electrode placemetn

87

Does a smaller electrode have a smaller or higher current density

Higher current density

88

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

Superficially

89

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

Deeper in tissues

90

What are the 3 ways to place electrodes

1. Monopolar
2. Bipolar
3. Quadrapolar

91

What are the 2 types of quadrapolar electrode placement

1. Intersecting
2. Non-intersecting

92

What is the purpose of tap key electrode (2)

1. Identify motor points
2. Stimulate small muscles

93

Who first introduced interferential current (IFC)

Ho Nemec in 1950

94

When did IFC come to North America

1980s

95

What is IFC

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

96

What do the 2 different carrier frequencies do

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

97

What is the beat frequency

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

98

What is interference

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

99

What are the 2 types of interference

1. Constructive
2. Destructive

100

What is constructive interference

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

101

What is destructive interference

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

102

What happens if the waves are perfectly out of phase

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

103

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

Interference

104

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

Heterodyne

105

What is the heterodyne effect seen as

The rising and falling waveform

106

True or False:
The beats correspond to the beat frequency and is the stimulation frequency of the waveform

True

107

What is the beat frequency

The difference between the two original frequencies

108

What is stimulating current pattern

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

109

Where does the maximum interference occur in IFC

The center

110

What are the types of IFC (4)

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

111

What is constant IFC

Both carrier frequencies are fixed

112

What is variable/quadripolar IFC

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

113

What is variable/quadripolar IFC used for

Minimize patient accommodation to the current

114

What is scanning IFC

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

115

What is stereodynamic IFC

Three distinct circuits that blend and create a distinct wave

116

Who developed the first high voltage pulsed current (HVPC)

Haislip with Bell laboratories in 1940s

117

Who did the first human study with HVPC

Thurman et al in 1971

118

What did Lehman do in 1974

Called HVPC high voltage electro galvanic stimulator

119

What does the term galvanic erroneous for

That current was not direct or continuous current but rater pulsed

120

What is HVPC

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

121

What is a twin peak monophasic pulse

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

122

What is the pulse duration of HVPC

Short from 100-200 usec

123

True or False:
HVPC are generally fixed by the manufacturer

True

124

True or False:
Some HVPC allow for adjustment of interspike interval

True

125

What is the pulse frequency of HVPC

1-200 pps

126

What does capacitance equal

Charge/voltage

127

Do high voltage sources have more or less capacitance

Less

128

Do low capacitance sources have high or low tissue impedance

Low tissue impedance

129

Are low tissue impedances more or less comfortable

More comfortable

130

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

True

131

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

Higher current amplitude

132

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

1. Electric nerve/muscle stimulation
2. Wound healing

133

Who created Russian Current

Yakov Kots in 1977

134

How does Russian Current effect human muscle contraction

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

135

Is the application of Russian Current painful or painless

Painless

136

Russian Current can cause what to happen in short term training

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

137

When was the first Russian Current stimulator produced in the US

1980

138

What is the clinical importance of Russian Current

You possibly train individuals without the need of voluntary contractions

139

True or False:
Russian Current is a time modification of continuous sinewave having carrier frequency of 2500 pps

True

140

How long is Russian Current burst modulated fixed for

10 msec periods

141

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

10 msec

142

What is the burst frequency of Russian Current

50 bursts per second (bps)

143

What is the carrier frequency of Russian Current

2500 pps

144

What is the burst duration of Russian Current

10 msec

145

What is the interpulse interval of Russian Current

10 msec

146

What determines the magnitude of effect

The total # of bursts/sec

147

What is each burst at the nerve muscle membrane treated as

A single pulse

148

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

Motor nerve depolarization and tetanic contraction

149

What are the physiologic effects of Russian Current (3)

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

150

What will higher current amplitudes stimulate

Deeper motor neurons

151

How are motor units activated with Russian Current

Preferential activation of type II motor units

152

When is motor unit recruitment deficient with Russian Current

During maximum voluntary muscle contraction

153

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

True (Dr. Stachura get cleared up)

154

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

Larger pool of type II motor units