electrotherapy Flashcards

1
Q

electrotherapy uses

A

strengthening, ROM, improved function, contraction of denervated tissue, tactile stimulation, wound healing, edema control, and pain modulation

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2
Q

electricity is measured in what

A

Coulombs (C) or micro coulombs (uC)

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3
Q

net gain of electrons =

A

negative charge

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4
Q

net loss of electrons =

A

positive charge

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5
Q

properties of electrical charge

A

like charges repel and opposite charges attract

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6
Q

anode =

A

net positive pole; attracts (-) ions

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7
Q

cathode =

A

net negative pole; attracts (+) ions

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8
Q

voltage definition

A
  • potential difference in distribution of ions
  • a force that pushes charge
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9
Q

voltage is also referred to as

A

electromotive force

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10
Q

voltage is measured in what

A

volts (V) or millivolts (mV)

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11
Q

current flow definition

A
  • flow of charged particles
  • moves from anode to cathode
  • current flow and electron flow are opposite
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12
Q

current flow is measured in what

A
  • amperes (A) or microamperes (uA) or as a rate (coulombs per sec)
  • measured as the number of electrons or ions that pass a certain point in a specified period of time
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13
Q

resistance/capacitance/impedance defintion

A

opposition to flow of charged particles

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14
Q

resistance/capacitance/impedance equation

A

I = V/R
- inverse relationship between resistance and intensity

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15
Q

resistance/capacitance/impedance alternating current equation

A

I = V/Z
Z = resistance above (I = V/R) + any additional resistance found in the capacitance and inductance of an alternating current generator

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16
Q

resistance/capacitance/impedance depends on what

A
  • nature of material
  • length of pathway
  • cross-sectional area of pathway
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17
Q

skin impedance

A
  • a form of resistance
  • resistance offered by the skin
  • highly variable throughout the body
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18
Q

skin impedance variables

A
  • water content
  • blood flow
  • patient activity or position
  • conducting medium
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19
Q

skin impedance fixed factors

A
  • distance between electrodes
  • what is under electrodes
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20
Q

direct current

A
  • unidirectional current flow lasting for at least 1 sec
  • since current flow is only in one direction will lead to an accumulation of ions under the electrodes
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21
Q

direct current uses

A
  • iontophoresis
  • wound healing
  • stimulation of denervated tissue
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22
Q

direct current cathode

A
  • depolarized membrane of excitable cells
  • alkaline effect
  • attracts hydrogen
  • liquefies protein
  • promotes fibroblastic migration
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23
Q

direct current anode

A
  • hyperpolarizes membrane of excitable cells
  • acid effect
  • attracts oxygen
  • coagulates protein
  • kills bacteria
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24
Q

alternating current

A
  • continuous current flow alternating direction at least once each second
  • can be identified by waveform
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25
Q

alternating current uses

A
  • stimulation of nervous and muscular tissue
  • may be used for denervated tissue
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26
Q

pulsed current

A

unidirectional or bi-directional current flow with periodic interruptions that only lasts a few milliseconds or less

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27
Q

pulsed current uses

A
  • most common form of e-stim used
  • used in most e-stim interventions except for iontophoresis
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28
Q

constant current

A
  • how the generator is going to act to resistance
  • stays fixed even if resistance or impedance changes; voltage varies
29
Q

constant voltage

A
  • voltage will remain constant and current will change in proportion to resistance or impedance changes
30
Q

amplitude

A
  • same as intensity
  • measured in Amperes more often millamperes; sometimes expressed in voltage
  • peak amplitude = highest intensity reached during one stimulus
31
Q

rise time and decay time gives shape to what

A

gives shape to the pulse/phase

32
Q

rise time

A

elapsed time from onset of stimulus to peak amplitude of stimulus

33
Q

decay time

A

elapsed time from peak amplitude to termination of stimulus

34
Q

rise time and decay time measured in what

A

milliseconds or microseconds; differs from “ramp and fall” time which are modulation to an individual stimulus

35
Q

pulse duration

A
  • length of time one pulse lasts
  • in a biphasic pulse can be broken into phase duration = length of time current flow in one phase of a pulse
36
Q

interphase or intrapulse interval

A

brief interruption between phases; measured in microseconds

37
Q

interpulse interval

A

elapsed time between consecutive pulses in a pulsed current; measured in microseconds

38
Q

total current

A

sum of peak amperage, pulse frequency and pulse duration

39
Q

pulse charge

A

based on duration and amplitude of phases in a pulsed current

40
Q

frequency (rate)

A
  • number of pulses or cycles per second
  • measured in pps in PC
  • measured in Hz in AC
41
Q

frequency (rate) values

A

low 0-1,000 Hz
medium 1,000-10,000 Hz
high >10,000 Hz

42
Q

change in frequency in AC will lead to what

A

will lead to an automatic change in cycle duration (inverse relationship)

43
Q

change in frequency in PC will lead to what

A

no change in pulse duration due to an interpulse interval

44
Q

does skin impedance increase or decrease with decreasing pulse or cycle duration?

A

decreases, therefore increasing frequency may increase current penetration

45
Q

is higher or lower frequency more comfortable?

A
  • higher frequency because skin impedance is reduced in AC current
  • higher frequency can lead to more fatigue tho
46
Q

relationship between frequency and recruitment of fiber type

A

type I: 10-20 Hz
type II: 30-60 Hz

47
Q

modulations defintion

A

any parameter that is altered or varied during a series of pulses or cycles

48
Q

modulations are usually seen in what

A

amplitude, frequency, phase duration or waveform

49
Q

what are burst modes?

A

multiple pulses or groups of cycles carried out in bursts

50
Q

what is the carrier frequency

A

number of pulses/second before burst modulation in AC current

51
Q

what is the burst frequency

A

burst occurring to deliver the carrier frequency

52
Q

what muscles are recruited in a voluntary contraction

A

small, slow deeper units are recruited first in an all or none fashion

53
Q

what muscles are recruited in an electrically stimulated contraction

A

larger, faster motor units fire first

54
Q

what is the biggest factor in which muscles are recruited during a contraction?

A

electrode placement; the closer the motor unit is to the electrodes the faster it will be recruited

55
Q

cell type recruitment order

A

sensory nerves > motor nerves > deep pain nerves > muscle fibers

56
Q

what is the strength duration curve

A
  • need adequate total current to get a response (all or nothing)
  • either have to increase amplitude or pulse duration to get the desired response
57
Q

what does the strength duration curve show the relationship between

A

amplitude and phase duration

58
Q

rheobase defintion

A

minimal amplitude needed to create an AP given an infinite pulse duration

59
Q

chronaxie defintion

A

minimal pulse duration that will cause an AP at 2x rheobase

60
Q

contraindications to electrotherapy

A

severe cardiac condition, use of demand type pacemaker, active bleeding or risk of hemorrhage, active osteomyelitis, pregnancy, carotid bodies, phrenic nerve, eyes, gonads

61
Q

precautions to electrotherapy

A

sensory loss, areas of scarring, thick adipose tissue, severe edema, over malignancy/neoplasm, open wounds, severe depression, disoriented patients, superficial metal

62
Q

do large electrodes increase or decrease skin impedance

A

decrease

63
Q

electrode location

A

have current run longitudinally

64
Q

unipolar or monopolar set up

A
  • one electrode is considered active based on its function or differences in size
  • use over motor point
  • delivery of medication
  • one small active electrode and one large dispersive electrode so current density is greater under the active one
65
Q

unipolar or monopolar uses

A

used for isolating single or small muscle groups whether innervated or denervated and for training functionally after transplant or repair

66
Q

bipolar set up

A
  • both electrodes are of equal size with equal current density under both
  • place one over the motor point and one distally over the nerve
67
Q

bipolar uses

A

used primarily to stimulate larger muscle and muscle groups for functional activities

68
Q

quadripolar uses

A

specific to inferential stimulation; circuits are crossed

69
Q

electrodes with DC set up

A
  • make the active electrode the cathode because it depolarizes excitable cells and make the anode dispersive
  • place active over the motor point and dispersive on the ipsilateral side not too close to the motor point and not to distance to the anode