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πŸ”΄ Electrotherapy πŸ”΄ > General Principles For Application Of Electrophysical Agents > Flashcards

General Principles For Application Of Electrophysical Agents Flashcards

1
Q

What is an electric current

A

The flow of electrons from an electron source to the wires and electrodes used to deliver it to the tissues

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2
Q

When does the electric current flow?

A

If there is a (potential) difference in the distribution of electrons between the two poles of electrical circuit

(Electromotive force)

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3
Q

Components of a circuit

A

Electro therapeutic device
Wires
Electrodes
Medium
Conductor

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4
Q

What is conductance

A

Ability to transmit charged particles

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5
Q

Electrons can move if there is a easy pathway which is the ____________________.

A

Conductor

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6
Q

Examples of conductors :

A

Carbon
Copper
Aluminium
Gold
(Metals)

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7
Q

What is a conductor

A

Material permits free movements of electrons

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8
Q

What is a capacitor

A

The ability to store charges

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9
Q

What is the most important capacitor in our body

A

Cell Membrane

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10
Q

What is a resistor

A

Materials resist the flow and have no free ions/electrons

(Materials that offer resistance to the electron flow)

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11
Q

What is resistance ?

A

Ability of a resistor to oppose the current flow

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12
Q

What is impedance

A

The opposition of our biological tissues to the flow of an electrical current

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13
Q

Both resistance and electrical impedance are measured in what unit?

A

Ohms (Ξ©)

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14
Q

Components of the device

A

Generator
Oscillator
Transformer
Rectifier
Filter
Regulator
Amplifier

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15
Q

Types of devices based on power sources

A

Small portable devices (battery)

Large clinical devices (electric current circuit)

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16
Q

Types of current

A

Direct current

Alternating current

Pulsatile current

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17
Q

What is direct current

A

Continuous unidirectional flow of charged particles for 1 second or longer

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18
Q

The direction of the flow is determined by what ?

A

Polarity

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19
Q

Another name for direct current

A

Galvanic current

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20
Q

Direct current is good for the treatment of what kind of muscles ?

A

Denervated muscles

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21
Q

Iontophoresis is an example of which type of current

A

Direct current

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22
Q

What is another name for alternating current

A

Faradic current

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23
Q

What kind of muscle is alternating current used for

A

Innervated AND denervated

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24
Q

What is alternating current

A

Continuous bidirectional flow of charged particles for 1 second or longer relative to the baseline (zero)

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25
Q

What is pulsatile current

A

Noncontinuous interrupted periodic flow of direct current OR alternating current

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26
Q

What direction does a pulsatile current flow in?

A

Can be UNIDIRECTIONAL (monophasic) or BIDIRECTIONAL (biphasic)

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27
Q

What are some current waveform shapes?

What can we conclude from current wave forms?

A

Waveform shapes:
- sinusoidal
- rectangular
- square
- spiked

Current waveform is a graphic presentation of:
- shape
- direction
- amplitude
- duration
- pulse frequency

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28
Q

What shape is this waveform ?

A

Sinusoidal

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29
Q

What shape is this waveform?

A

Rectangular

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30
Q

What shape is this waveform?

A

Spiked (twin-spiked)

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31
Q

What is meant by monophasic current ?

A

A pulse or cycle that moves in only ONE direction from the zero baseline to return to it after a finite time

(Unidirectional)

32
Q

What is meant by biphasic current ?

A

A pulse or cycle that moves in ONE DIRECTION and then in the OPPOSITE DIRECTION from the zero baseline to return to that baseline after a finite time .

(Bidirectional)

33
Q

Biphasic current may be ______________________ or _____________________.

A

Symmetrical
Asymmetrical

34
Q

What is meant by SYMMETRICAL biphasic current

A

A pulse or cycle with the positive phase geometrically IDENTICAL to the negative phase.

35
Q

What is meant by ASYMMETRICAL biphasic current

A

A pulse or cycle with the positive phase geometrically DIFFERENT to the negative phase.

36
Q

Asymmetrical biphasic currents can be either _________________ or __________________.

A

Balanced
Unbalanced

37
Q

What is meant by BALANCED asymmetrical biphasic current

A

Biphasic pulse or cycle with EQUAL charges in each phase

38
Q

What is meant by UNBALANCED asymmetrical biphasic current

A

Biphasic pulse or cycle with UNEQUAL charges in each phase

39
Q

What is a pulse ?

Is it monophasic or biphasic ?

What is another word for pulse ?

A

A current flow in each direction of the phases for a determined period of time

Can be either monophasic or biphasic

Cycle

40
Q

What is a phase

A

The period of time, collapsing from the beginning to the end of one phase, usually expressed in microseconds or milliseconds

41
Q

Pulse duration (width) vs Phase duration (width)

A

Pulse duration:
-period of time from the beginning to the end of TWO phases within a pulse or cycle
- INCLUDING interphase duration (time between 2 phases)
- expressed in microseconds or milliseconds

Phase duration:
- period of time from the beginning to the end of ONE phase
- Expressed in microseconds are milliseconds.

42
Q

Highlight the pulse duration in this image

A
43
Q

Highlight the phase duration in this image

A

Phase duration A is separate from Phase duration B

44
Q

Highlight the interphase (intrapulse) duration in this image

A

NOTE:
- Inter = between
- Intra = within

45
Q

Highlight the interpulse duration in this image

A
46
Q

Interpulse interval VS Interphase interval

A

Interpulse interval :
- Time between two successive pulses/cycles
- Expressed in microseconds or milliseconds.

Interphase duration:
- Time when the current is not flowing between two phases of a pulse
- Expressed in microseconds or milliseconds.

47
Q

Where is the interphase (intrapulse) interval in this image

A

There is none (no space between the phases)

48
Q

Describe the interpulse and interphase durations in alternating current

A

Alternating current DOES NOT have interphase NOR interpulse duration

Length of time a cycle lasts is called CYCLE DURATION

49
Q

What does a direct current DC not have?

A

No phases
No pulses
No cycles

50
Q

What is current amplitude

What is the unit for current amplitude

A

The magnitude of current to the isoelectric (zero) baseline

Unit: amperes

51
Q

What is the peak amplitude

A

Maximum amplitude which is the highest point of each phase

52
Q

What is pulse charge

What is the unit of pulse charge

A

The total amount of electricity being delivered to the patient during each phase

Unit: Coulombs or micro-coulombs

NOTE: you can calculate the pulse charge from the graph by adding (phase charge A + phase charge B = pulse charge)

53
Q

What is frequency (rate)

Unit of frequency

A

The number of times per seconds that a pulse, cycle, bursts, or beat will repeat itself

Unit: Hertz (Hz)
(Or pulse/sec, burst/sec, cycle/sec etc)

54
Q

Relationship between frequency and cycle duration in alternating current AC

A

Inversely proportional

55
Q

Relationship between frequency and pulse duration in pulsatile current PC

A

NOT RELATED

Change in frequency will NOT affect pulse duration

56
Q

Describe the Types of current frequencies and provide examples if possible

A

Low frequency current (1 - 2000 Hz)
- meets 3200 Ξ© skin resistance at 50 Hz
- examples: Diadynamic (DD) and ES (i think she means electrical stimulation?)

Medium frequency ( 2000 - 10,000 Hz)
- meets little skin resistance
- stimulates sensory and motor fibers
- examples: IF and TENS

High frequency (10,000 Hz and above)
- has NO effect on sensory and motor fibers (because its too fast so it just passes them)

57
Q

What is meant by current modulation

A

Automatic variations in amplitude, pulse or cycle duration, or frequency of current during a series of pulses or cycles.

58
Q

What is meant by ON time and OFF time

A

ON-TIME: period when current is being delivered (seconds)

OFF-TIME: period when NO current is being delivered (seconds)

(Related to current modulation)

59
Q

What is meant by RAMP UP and RAMP DOWN

A

RAMP-UP: increase in amplitude ⬆️

RAMP-DOWN: decrease in amplitude ⬇️

(related to current modulation)

60
Q

To conduct electrical current to the patient’s body , what do we need?

A
  • Different types, shapes, and sizes of electrodes
  • Conductive substance (ex: gel, water, soaked sponge)
  • Wires attach the electrodes to the treatment device
61
Q

What type of tissue are considered the best conductors of electricity ?

Order them from strongest to weakest .

A

Tissue with high water content which have high ion content are considered best conductors of electricity

Blood (best conductor) > Muscle 75% > Fat 14% > Bone 5%

62
Q

Why do we prepare the skin before treatment? How do we prepare it ?

A

Skin offers primary resistance to current flow and is considered as an insulator .

To overcome it we have to prepare the skin by:
- clean the skin (from oil etc)
- clip hair if necessary
- appropriate coupling medium
- adequate contact

63
Q

What to consider when setting up electrodes

A

Electrode size

Number electrodes

Position of electrodes

Distance between electrodes

Orientation of electrodes

Electrodes polarity

64
Q

Purpose of different sizes of electrodes

A

Small electrode for small areas
Large electrode for large areas
Pointer electrode for facial muscles (ex: Bell’s palsy, facial palsy or paralysis)
Uneven sizes ( smaller electrode gives more current)
Dispersive electrode remote from treatment area

65
Q

Current density is higher under which size of electrode

A

Small electrodes have higher current density

66
Q

What is A and B

A

A is Rise Time

B is Decay Time

67
Q

What determines the number of electrodes required

A

Size of treatment area

(Can use multiple channels to add electrodes)

68
Q

Different positions of electrodes

A

Monopolar
Bipolar
Quadrapolar
Etc.

(Placed on motor point or dispersive)

69
Q

Purpose for different distances between electrodes

A

Close together = Superficial and more current density in the skin

Further apart - Deep

70
Q

Orientation of electrodes

A

Parallel to the direction of muscle fibers

Along nerve trunk and on motor points

71
Q

Electrode polarity

A

Cathode (NEGATIVE) electrode : has great level of electrons
Anode (POSITIVE) electrode

(Important for Diadynamic)

72
Q

Basic physiology of nerve excitation

A

Resting membrane potential is between -60 mV and -90 mV (no action potential )

Stimulus

Action potential = depolarization

Repolarization back to resting membrane potential

73
Q

Order of nerve recruitment depends on :

A

Type of nerve fibers
( sensory > motor / myelinated > unmyelinated)

Size/length of nerve fibers
(Short > long)

Diameter of nerve fibers
(Small > large)

Location of nerve fiber with respect to electrode
( superficial > deep)

74
Q

Superficial nerves are _______________ nerves

A

SENSORY

75
Q

First muscle fibers to be stimulated are :

A

Large fast twitch muscle fibers > Small slow twitch muscle fibers

76
Q

Effects of electrical current on stimulated tissue ( 3 types of neurophysiological responses)

A
  • Sensation (sensory)
  • Skeletal muscle contractions (motor)
  • Pain (noxious level)

(IN THAT SPECIFIC ORDER)

πŸ”΄ Electrotherapy πŸ”΄ (6 decks)

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