Electrotherapeutic Basics Flashcards
(154 cards)
1
Q
What 3 things must be present to have a current
A
- A source of electrons
- A conductor of the electrons
- A driving force of electrons
2
Q
What are atoms that possess charge known as
A
Ions
3
Q
Where do ions move from and to
A
From areas of high concentrations to areas of low concentrations
4
Q
What is the net movement of charged particles along a conductor
A
Current
5
Q
What is the amount of potential (electrical) difference between two points ([ions] or electrons) in an electrical field
A
Electromotive force (EMF)
6
Q
What does the electromotive force do
A
Drives the charged particles that are measured in volts
7
Q
What size electromotive does the commercial current flowing from a wall outlet produce (2)
A
- 110-115 V
2. 220-240 V
8
Q
True or False:
Electrotherapeutic modalities modify voltage for specific therapeutic purposes
A
True
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
10
Q
What makes an electrotherapeutic modality a low voltage generator
A
Produces a voltage less than 150 V
11
Q
What makes an electrotherapeutic modality a high voltage generator
A
Produces a voltage greater than 150 V
12
Q
What is a coulomb (C)
A
The measure of electric charge equal to 6.25*10^18 electrons
13
Q
What is an ampere (A)
A
The measure of current flow equal to 1 C per second
14
Q
What is an Ohm (omega)
A
Measure of resistance to current flow
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
16
Q
What is resistance (Ohms)
A
The ability of a medium to resist the flow of electrons through direct current
17
Q
What is inductance
A
Opposition to electron flow created by electromagnetic eddy currents generated when current is passed through a wire
18
Q
What is capacitance
A
Ability of a material to store an electrical charge
19
Q
What is impedance
A
Resistance + inductance + capacitance
20
Q
What are conductors
A
Materials that offer little resistance and allow current to flow easily
21
Q
What are insulators
A
Materials that offer high resistance to current flow
22
Q
What are semiconductors
A
Materials that offer neither high nor low resistance to current flow
23
Q
What is the pump of water flow equal to in electron flow
A
Volts
24
Q
What is the gallons of water/min equal to in electron flow
A
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
