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Passive Care Exam One > Electrical Stimulation > Flashcards

Flashcards in Electrical Stimulation Deck (65)
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1
Q

What are the physiological effects of electrical stimulation?

A
1 decrease pain
2 decrease muscle spasm
3 reduce edema
4 stimulate exercise by muscle contraction
5 stimulate healing
2
Q

By what concept does electrical stimulation decrease overall pain?

A

Gate-Control theory/endorphin release

3
Q

What is the gate control theory and how does it work?

A

Theory that explains how non-painful input closes the “gates” to painful input, therefore preventing pain sensation from traveling to the CNS.

4
Q

What 3 things are required for electricity to work?

A

1 source of electrons
2 driving force
3 path (conductor)

5
Q

What is the river analogy in terms of electricity?

A

Electrons = drops of water in a river
Current (Amp) = flow of the river
Voltage = waterfall
Resistance = water flow through hose

6
Q

Is there more or less resistance with a short smooth large diameter hose/wire?

A

Least

7
Q

What does the term capacitance mean?

A

ability of a material to store a charge (to release later)

8
Q

What is Ohm’s Law?

A

V = IR

9
Q

What is another name for a monophasic current?

A

Direct current (DC) or Galvanic

10
Q

What type of current has current flow in one direction?

A

Monophasic/direct current (Galvanic)

11
Q

What is another name for a biphasic current?

A

Alternating current

12
Q

What type of current has an electron flow that changes directions regularly?

A

Biphasic current/alternating current

13
Q

Which type of wave form has the same shape in both phases? Different shapes?

A
Symmetrical = same shapes
Asymmetrical = different shapes positive and negative
14
Q

What are the shape variations possible with a biphasic current?

A

Sinusoidal, square, rectangular, triangular

15
Q

What is the term for the time it takes the current to leave the isoelectric line to when it returns to that line?

A

Phase duration

16
Q

In what type of current are the phase duration and pulse duration the same?

A

Monophasic

17
Q

What type of current has two phase duration for each pulse?

A

Biphasic current

18
Q

Do tissues respond to phase duration or pulse duration?

A

Phase duration

19
Q

The phase duration must be how long (in general) to cause an action potential?

A

Long enough to overcome capacitance

20
Q

Do small or large diameter nerves have low capacitance and therefor reach threshold quickly?

A

Large diameter

21
Q

What is the space called in between each pulse duration?

A

InterPulse duration

22
Q

What is the term used to describe the intensity or magnitude of the current?

A

Amplitude

23
Q

Which fibers are close to the skin and have a lower threshold, so they are stimulated first?

A

A-beta

24
Q

Which response is elicited first: sensory or motor?

A

Sensory

25
Q

What is the term for the amount of current supplied over a period of time?

A

Average current

26
Q

Why can too high average current be an issue?

A

Can cause tissue damage

27
Q

What measurement describes the relationship between the amplitude (strength) of the electrical current and the phase duration?

A

Strength duration curve

28
Q

Does a short or long duration require a higher amplitude for the nerve response?

A

Short

29
Q

What kind of duration allows for a lower intensity for the same nerve response?

A

Long

30
Q

How can the phase charge be altered?

A

Changing the phase duration and amplitude

31
Q

When the patient reports tingling but no muscle twitch, what fibers have been exceeded and which fibers have not been reached?

A

A-beta fibers exceeded

A-alpha motor neurons not reached

32
Q

What happens when A-alpha motor neurons are reached?

A

Muscle contraction

33
Q

When the patient reports a burning, needling sensation, the capacitance of which fibers have been exceeded?

A

A-delta fibers

34
Q

Does electrical stimulation target nerves or the actual muscle?

A

Nerves (targeting the actual muscle would be painful)

35
Q

What is the order in which fibers are reached via electrical stimulation to initiate certain responses?

A

1 A-beta (tingling)
2 A-alpha (muscle contraction/twitch)
3 A-delta (discomfort)
4 C (PAIN)

36
Q

What is rheobase?

A

Minimum amplitude needed to depolarize a nerve fiber when phase duration is infinite

37
Q

What happens if the peak amplitude fails to exceed rheobase?

A

the nerve will not depolarize regardless of phase duration

38
Q

What is chronaxie?

A

The time (or phase duration) required to depolarize a nerve fiber when the peak current is twice rheobase

39
Q

When will the patients reach the greatest amount of comfort in terms of phase duration and amplitude?

A

When amplitude is twice rheobase and phase duration is slightly greater than chronaxie

40
Q

What is the term for the number of pulses or cycles generated per second?

A

Frequency

41
Q

What affects the number of action potentials elected during the stimulation?

A

Frequency

42
Q

Does a higher or lower frequency lead to summation?

A

Higher

43
Q

What is the rate limiting factor of the number of impulses that can be generated by a nerve?

A

Absolute refractory period

44
Q

What occurs with stimulation at high frequency near the refractory period of the sensory nerve (official name)?

A

Wedenski’s inhibition

45
Q

What are the most common treatment frequencies?

A

1-10 Hz or 60-100 Hz

46
Q

What are the values for low, medium, and high frequency generators?

A
Low = up to 1,000 Hz
Medium = 1,000-100,000 Hz
High = greater than 100,000 Hz
47
Q

What is the frequency for interferential current generators?

A

4,000-5,000 Hz

48
Q

What is the main purpose for using high frequency generators?

A

Thermal purposes (ex. = diathermy)

49
Q

What is the normal frequency level for Russian stimulation?

A

2,500 Hz

50
Q

What structure attaches the electrodes to the current generator?

A

Leads

51
Q

How many leads must there be to complete a circuit?

A

Two

52
Q

If the electrodes are unequal sizes, to where will the current concentrate?

A

In the smaller electrode (perception of increased intensity)

53
Q

What happens to the larger electrode when the sizes vary greatly?

A

Unable to perceive current - becomes dispersal electrode

54
Q

What is the main target when two pads are placed close together?

A

Most concentration in superficial tissues

55
Q

How does the target change when the pads are further apart?

A

Current has potential to take deeper path through the nerve and blood vessels that have less resistance

56
Q

What is the general rule for selecting the size of the electrodes?

A

Largest possible but small enough to selectively target tissue

57
Q

What is the size of the electrodes during monopolar electrode configuration?

A

Two or more unequal sizes (one active, one dispersal)

58
Q

Monopolar electrode configuration can be used with what types of current?

A

Biphasic (AC) or monophasic (DC)

59
Q

Which is found at the target site, and which is found away from the target site: active or dispersal electrode?

A

At target site = active

Away from target site = dispersal

60
Q

Bipolar electrode configuration can be used with which types of currents?

A

Monophasic (DC) and biphasic (AC)

61
Q

What is the size and location of the electrodes with a bipolar electrode configuration?

A

Equal size both placed over treatment site

62
Q

Bipolar electrode configuration is most common for what kind of treatment?

A

TENS (transcutaneous electrical nerve stimulation)

63
Q

Quadripolar electrode configuration is most common with what kind of treatment?

A

Interferential current

64
Q

How are the electrodes arranged during quadripolar configuration?

A

Two separate medium frequency current with electrodes placed as cross currents

65
Q

What is the significance of the cross currents of quadripolar configuration?

A

Current is interfered with in the center of the two currents