Electrical Therapy Overview (Lecture 0 - from last test) Flashcards
Polarity is
the net charge of the object
The amount of attraction or repulsion by an electric field is
Voltage
* The amount of energy required to move current
* This high voltage is what puts electricty down power lines
Units for voltage
Joules/Coulombs (Force*m /Net charge)
m = distance
Neural communication occurs due to changes in change (think depolarization / repolarization)
Materalis in which ions and electrons can move freely are called
* give some examples of these (2 outside human 2 inside)
Conductors
Metals / water
Muscle, nerve, bodily fluid
Materalis in which charged particals do not move freely
Give some examples of these (2 inside human 2 outside)
Insulators
Rubber / plastic
Fat tissue / bone
Theres a powerline down in a puddle of water. Why would it not be safe to step in it?
Because water is a conductor and could put that electricity into you
This is why there is plastic around wires (acts as an insulator)
The movement of ions/electrons in response to voltage force
Current
What is current directly proportional to?
Voltage
current = the movement of ions/electrions in response to voltage force
* so these ions move in response to the amount of voltage pushing them
* if you have more voltage you’re going to have a faster current
voltage = the amount of energy required to move current
These wheels are churning in such a way to facilititae water moving. The amount of energy required to move those wheels at that speed is the voltage
what is current measured in?
A or mA
What is OHM’s Law
Current (AMP) = Voltage / Resistance (ohm)
Resistance in the body
* Skin
* Hair
* fascia
* Ligament
* Callus
* Fat
* Bone
* Tendon
* Scar
Which image has more voltage?
A
because the voltage being high makes the current go faster
Would something with more water in it have more or less resistance?
More water = decreased resistance
If we have high resistance how do we keep the same amount of current?
Increase the voltage
Current (AMP) = Voltage / Resistance (ohm)
So if someone has hairy legs (resistance) we would increase the voltage to keep the same current of electricity going into them
KNOW: Someone w/ excess adipose tissue would need more estem because fat is an insulator
Of adipose fat, ligament, skin and bone which one would have the most resistaance and why?
Bone because it has the least water (which is a conductor)
Which kind of current is continuous and unidirectional?
Direct current
Always flowing in one direction
A direct current can flip to being negative or even have gaps in it. However it must always flow on direction for how many seconds before flipping or stoping
1 second
KNOW: with a direct current you’re going to need a cathode and an anode. Which one is positive and which one is negative?
Cathode = negative charged current going in it.
* Think its a negative experience to have a cathiter
Anode = positive charged current going in it
* analgesic is positive
In the picture below we have a negative cathode which is driving the negative current out of the area and going to the anode (which is positive so it attracts that displaced negative current)
* Utilized w/ iontophoresis (anti inflammatory by being negatively charged which drives the other negatives away from the area making it more positive) - think using this for tendon pathologies (inflammation itis)
What kind of current is uniterrupted bidirectional flow of ions/electrons?
Alternating current
Rather than it being consistent then switching (direct current) its switching the entire time
How often does an alternating current switch directions?
At least 1 time per second
What are the two kinds of Alternating current?
Burst modulated Alternating current (normally skeletal muscle stimulation)
Amplitude modulated Alternating current
What two kinds of currents are burst modulated alternating currents?
Russian / Aussie currents
What is the one kind of amplitude-modulated alternating current?
Interferential current
KNOW: Pulsed current is a modulated direct current or modulated alternating current
are these pulsed currents alternating or direct?
Direct because they go the same direction for more than one second (in this picture they never change directions, just take breaks)
NOTE: We change the amplitude / duration of the currents to make them look like triangles / rectangles /squares
Which one delvers the most current into the body?
Rectangle
Duration is longest and amplitude is the same
What is a pulse?
One electrical event
would be the top ones the picture below
What is a burst?
One or more pulses combined and separate from another group of pulses
* used most often in skeletal muscle stimulation
What is a carrier frequency?
Frequency of the little waves inside the burst
a lot of times this is preset
What is burst frequency?
How many bursts per second
What is a biphasic pulsed current?
All the little pulses are in positive AND negative directions
Is this monophasic or biphasic?
Monophasic (dont switch direction)
**
Is this monophasic or biphasic?
Biphasic - switch directions
A pulse is defined as one electrical event - notice it can go negative and positive and still be one electrical event as long as theres no break between
Notice the difference between phases and pulses
* pulse = 1 electrical event
* phase = the amount of time it stays negative or positive w/o a break
Documentation:
* waveform type and shape (symmetrical / asymetrica / mono-/biphasic / square, tectangle, triangle, ramp up / ramp down
* Pulse frequency
* Pulse duration
Which nerve are considered large diameter nerves?
Which nerves are stimulated next
next
Alpha a nerves: Proprioception / motor nerves
Beta nerves: Touch / pressure
Delta nerves: Pain / temperature:
* So if they’re experiencing a change in temperature then were giving way to much stimulation because these nerves are fairly small and should not be turned on
What kind of current is this?
Alternating
What kind of current is this?
Burst modulated alternating current
What is burst frequency for russian? (how many times per second a burst happens)
What is carrier frequency for russian (how many small waves happening in each burst)
50Hz
2,500 Hz
essentially the top one in the picture below is scrunched up into each burst (will alternate 2,500 times to = 1 burst)
What is the duty cycle for russian?
50% (the on and off times are =)
They shortened the burst duration but increased the burst frequency
Evidence suggests:
* greater torque production
* effiency
* decreased rate of muscle fatigue
* (compared to russian)
beucase this is a shorter one there will be decreased m fatigue (because the time under tension is a little bit less)
High volt pulsed current primarily used for tissue repair / wound healing
Current of high amplitude that are twin peaked and monophasic (always in the same direction)
* Now were dealing w/ a polarity (driving negative or positive)
very high peak voltage
Much shorter pulse duration
Very low duty cycle
this doesnt cause tissue damage because were delivering it so quickly
* think about just touching a hot stove for a milisecond - you wont burn yourself
One electrode placed on treatment area, other is away from treatment site
* this will produce a polarity (driving current)
KNOW: that because it has a high voltage our duty cycle, pulse duration, and duty cycle are very small (because out intensity is so high)
used for tissue repair and wound healing
Interferential current (IFC) - most common types for PAIN MODULATION
You’re going to deliver two currents.
* there will be 2 electrodes each with their individual currents
* The 2 currents will be directed to intersect (criss cross)
* The pulse shape will vary depending on the currents of each pad
* most of the time your frequency will be much higher in kilohurts instead of hurts
* You always put them in a criss cross fashion because the two currents are placed so they intersect with your treatment in the center
* Peripdocially they waves will since and produce a megawave because the combine or have summation (waveforms add together)
* they can also cancel each other out when one wave is coming in positive and the other one is in the nagtive zone at the time
With this one were modulating the amplitude
* We essentailly will change the amplitude to change the intensity instead of creating bursts of waves and gaps between (there are waves the entire time - its just the size of those waves that we care about)
NOTE: The “beats” are the high points of those waves (where 2 sum together perfectly to create a high point)
Beat frequency = how often the waves sum togther and createa a maximal peak
For muscle tetany beat frequncy = 50hz
* so for muscle contraction you would want to go below that
for pain modulation beat frequency = 100hz
* used for this most
Things we can change within IFC
Sweep:
* this modulates the beat frequency (how often we hit those high peaks)
* So we can have a high or low beat frequency during the treatment
* How often those waves come togteher
Vector scan:
* Increases the size of treatment area
* Remember treatment area is normally in the center (where they criss cross)
* With this it can increase the treatment area
* If you want to be very focused w/ your treatment = leave vector scan off
* With vector scan on we increase the size of our treatment area
KNOW: electrodes should be applied in a crisscross pattern w/ treatment area in the center
Premodulated IFC: intereference happens before they go out - so you don’t need to put the electrodes out in a crisscross manner (premodulated happens within the unit)
* A version of IFC where intereference occurs inside unit prior to being applied to pt via electrodes
*
Microcurrent (Low intensity DC)
intensity = Below 1 miliamp
* Because this is so low we can use direct current
* Insufficent to depolarize sensiry or mtoor nerve = this makes it good for tissue healing
* staying below the radar
Pulse duration = 0.5 seconds = makes sense because amplitude is so low
Typically a higher frequency because amplitude is so low
Cathode (negative) = on the treatment side
* Drive negative out and create a more positive unflux of potassium to create a more permiable cell membrane (make it depolrize again?)
Anode (positive)
Skin injury: we want positive ions from deeper tissues to go to the skin to promote healing
* Drive out positive charge so that new positive comes in
We put cathode over wound side (negative) to drive out the other negative
* dermal wounds (cathode over wound site)
* Increase fibroblast and granulation activity (because we drove out the other positive that was there this rushes in)
Only used in out patient clinic for wound care
Symmetrical Biphasic pulsed current
reversed Direct current then interupted and repeat
more tolerable than russian
can be burst modulated
