GRFC - electrotherapy Flashcards
Electricity
Form of energy composed of atoms
Proton (+)
Neutron
Electron (-)
Voltage/ electromotive force
Force that moves or drives electrons
Unit of measure: Volt
Current/ current intensity
Net flow of electrons
(+), (-), or both (+) and (-)
Unit of measure: Ampere
Resistance
Opposition to electron flow
Unit of measure: Ohm
Ohm’s law
I = V/R
Conductor
Facilitates electron flow or flow or electricity
Examples include H2O, metals, among others
Resistor/ insulator
Resists electron flow
Ions
Charged particles
Cation (+)
Anion (-)
Electrotherapy
The use of electric current and its variants in rehabilitation and treatment
Differences between cathode and anode in terms of
- pH
- risk for burns
- skin color
- polarization
- NCV
- effect
- function/indication
(pH)
- anode acidic
- cathode basic
(risk for burns)
- anode less risk
- cathode more risk
(skin color)
- anode pinkish hyperemia (blush)
- cathode mottled red
(polarization)
- anode hyperpolarization
- cathode depolarization
(NCV)
- anode decrease NCV
- cathode increase NCV
(effect)
- anode sclerosis (hardening)
- cathode sclerolysis (softening)
(function/indication)
- anode wound closure, skin hardening
- cathode disinfection
Law of magnetism
Opposite charges attract
Like charges repel
Electrotonus
Anelectrotonus: decreased muscle activity caused by anode
Catelectrotonus: increased muscle activity caused by cathode
Pleuger’s law/ polar formula/ Erb’s formula
For normal or innervated muscles, or for those with UMNL:
-COC-ACC-AOC-COC
For those with denervated muscles, for those with LMNL:
-ACC-COC-COC-AOC
NOTE:
- COC: cathode opening circuit
- CCC: cathode closing circuit
- AOC: anode opening circuit
- ACC: anode closing circuit
Resting membrane potentials
Muscle: -90mV
Nerve: -70mV
Heart: -88mV
GIT: -56mV
Electrical properties of nerves
- Electrical excitability/ resting membrane potential
- Refractory period
- Accommodation
Factors affecting resting membrane potential
- Speed
- Intensity
- Duration
Types of refractory period
Absolute refractory period:
-No AP can be generated even with supramaximal stimulus
Relative refractory period
-AP can be generated with supramaximal stimulus
Accommodation
Decreasing intensity as the body adapts
Dubois Raymond law
A sudden change in current intensity is needed to stimulate a nerve
Types and characteristics of currents
LFC
- frequency (Wadsworth): 1Hz to 2000Hz
- frequency (O’Sullivan): 1Hz to 1000Hz
- affects innervated and denervated muscles
- for motor purposes
- AC, DC, ES, FES, NMES, TENS (value)
MFC
- frequency (Wadsworth): 3000Hz to 6000Hz
- frequency (O’Sullivan): 1000Hz to 10000Hz
- affects innervated muscles
- for sensory purposes
- IFC, Russian current, TENS (effect)
HFC
- frequency (Wadsworth): >500000Hz
- frequency (O’Sullivan): >10000Hz
- does not affect nerves
- for thermal purposes
- UTZ, SWD, MWD, IRR-UVR, LASER
Direct/ monophasic/ Galvanic current
One phase/ polarity
Best for wound healing (especially high volt pulsed Galvanic current (HVPGC))
Best for denervated muscles (especially rheobasic current)
Types of direct current
Direct continuous/ direct uninterrupted:
No off-time or pulsed interval
For iontophoresis
Incrased risk for medical Galvanism (burn, fatigue)
Direct pulsed/ direct interrupted:
With off-time
Decreases risk for burn or fatigue
Types of direct interrupted/ direct pulsed current
Short DIC/ Faradic type Frequency: 50Hz to 70Hz Pulse duration: 0.02ms to 1ms Application: Tetanic contraction Sensation: Marked stabbing Use: For innervated muscles
Long DIC
Types of long direct current/ long direct interrupted current
Rectangular long DIC/ quick rise
Frequency: no fixed
Pulse duration: 1ms - 600ms
Use: For innervated, denervated muscles
Sharp long DIC/ exponential progressive current/ slow rise
Frequency: 300ms - 1000ms
Use: For denervated muscles
Forms: Triangular, saw-toothed, trapezoid
