Electrotherapy Flashcards
1
Q
Force created in electrons between two poles is referred to as ______, -______, or ______
A
electromagnetic force
potential difference
voltage
2
Q
Cathode
A
negative
high electron concentration
3
Q
Anode
A
positive
low electron concentration
4
Q
Current
measured in …..
A
rate of movement of charged particles
amps or milliamps
5
Q
Charge is measured in
A
coulombs
6
Q
Amp is a
A
coulomb of electrons per second
7
Q
1 amp is the current when 1 ____ passes a single joint in 1 second.
A
coulomb
8
Q
Voltage=
A
current x resistance
9
Q
Voltage measures
A
flow of current
10
Q
Greater the voltage….
A
the deeper we can drive the current into the body
11
Q
Resistance is
it is measured in ___ with direct currents and ___ in alternating.
A
opposition to movement of charged particles
ohms
impedence (Z)
12
Q
Capacitance determines …..
Tissues with low capacitance do what? and high capacitance?
A
effects of current flow in the body
accommodate to stimulus easily
does not or it dissipates the charge
13
Q
Flow is the result of …
A
the interaction of force (voltage) and resistance (ohm)
14
Q
Power is …
A
voltage multiplied by current
15
Q
Ohm’s law
A
current is directly proportional to voltage and indirectly to resistance
16
Q
Conductors in the body
A
muscle, nerve, loose collagen, tendon, ligament
17
Q
Insulators in the body
A
fat, skin
18
Q
What is the poorest conductor in the body?
A
bone
19
Q
Nerve conducts how many times faster than muscle?
A
6x
20
Q
Law of Dubois Reymond
Current effectiveness depends on three major factors:
Adequate intensity to ___ ____.
Current onset fast enough to ___ ____.
Duration long enough to ____ ____ of tissue. As phase duration increases, less ____ is required for stimulation.
A
the variation in current density, rather than the absolute current density, causing the depolarization of nerves or muscle tissue
reach threshold
reduce accomodation
exceed capacitance
amplitude
21
Q
Coulomb’s law
A
opposites attract
22
Q
Direct current: aka \_\_\_\_ \_\_\_\_ What is it? Commonly used for \_\_\_\_ and \_\_\_\_\_. Used for \_\_\_\_\_ \_\_\_\_ in denervated muscle.
A
galvanic current
continuous, unidirectional flow of charged particles (electrons)
iontophoresis & low voltage stimulation
muscle contractions
23
Q
Alternating Current:
What is it?
Decreases skin ___ and is more comfortable.
Used for ____ in _____ and ____ in _____.
A
continuous, bidirectional flow of electrons
resistance
pain control in IFC
muscle contraction in Russian
24
Q
Associated Terminology with alternating current: Amplitude Peak-to-peak amplitude Frequency Phase Pulse Pulse duration
A
max distance the wave rises and falls below baseline
distance from peak on positive side to peak on negative side of baseline
number of times the current reverses direction in 1 second
current flow in one direction for a finite period
portion of current flowing from baseline to max in one direction and back to baseline (may contain one or more phases)
amount of time required to complete one full cycle
25
When frequency is increased, a ____ _____ _____ may result. Below this, a twitch response occurs.
Cycle duration and frequency are ____ related.
tetanic muscle contraction
inversely
26
Pulsed current is ...
interrupted flow of charged particles where the current flows in a series of pulses separated by periods where no current flows.
most common
27
Monophasic
| Uses
unidirectional flow of electrons
only one phase per pulse
high voltage pulsed stim for muscle contractions and pain control
28
Symmetry refers to...
amount of time and amplitude of each phase of the pulse
29
Symmetrical phases..... example?
Asymmetrical
Balanced.... example?
Unbalanced.... example?
each phase has equal, but opposite, electrical balance; neuromuscular electrical stim
when these are used, each phase should be considered separately
if charges of both phases are equal, the pulse is electrically balanced, otherwise it is unbalanced; TENS for pain control because net electrical charge over time is zero.
When the charges of both phases are not equal, the pulse is unbalanced; neuromuscular electrical nerve stim
30
Tissues only respond to ___ duration not ___duration.
phase not pulse
31
Large diameter nerve fibers have ___ capacitance. They ___ store charge and action potentials results ___.
Small diameter nerve fibers have ___ capacitance. They ____ store and there is a ____ disturbance in the membrane.
low
cannot
quickly
high
can
minimal
32
Which nerves are the most easily excitable? Why?
| Which ones take longer and why?
sensory
can reach AP with a short phase duration
C-fibers and muscle membranes, need longer phase duration
33
What impulses are used for sensory stimulation?
| For motor stimulation?
short pulses and low-current amplitudes
longer pulses and higher amplitudes
34
Large fibers have ___ threshold to depolarization from externally applied electric current.
Large fibers offer ___ resistance to ion movement and therefore conduct action potentials faster.
Larger fibers will display conduction failure before ____ in the presence of asphyxia/anoxia, compression and cold.
Smaller fibers will display conduction ___ before larger in presence of anesthetics or toxins.
lower
less
smaller
failure
35
The more voltage difference we introduce with e-stim, the more nerves.....
This means more .....
are depolarized
sensory or muscular activity
36
If charge delivered is sufficient to overcome capacitance of nerve fiber, it will ___.
If amplitude is not high enough despite phase duration...
depolarize
the threshold will not be reached and it will not depolarize
37
Low frequency <1,000 Hz used in...
Medium frequency 1,000-100,000 Hz used in....
High frequency >100,000 Hz used in....
TENS
IFC & Russian
heating
38
Duty cycles:
| Extrinsic vs intrinsic
imposed by clinician to interrupt current to create rest time
modulated wave form; when pulses are packaged into small clusters or burst mode
39
Electrodes closer together will....
result in superficial current density
40
```
In monopolar set up:
How many are used?
One lead is ... and the other?
Active lead (small) at... and other ....
Treatment is focused where?
Larger pad does what?
Polarity is used for?
```
2 or more
small, large
target site, away
small electrode
disperses and completes circuit
iontophoresis and wound healig
41
Bipolar set up
equal in size and it results in equal current density under them
one electrode is placed under motor point, other is not.
42
Quadripolar set up:
uses. ...
placed. ...
techniques. ..
2 completely separate medium-frequency generators with the same unit
cross currents
current can be aligned so it is concentrated between electrodes to localize stimulation
or
L and R side
43
Three mechanisms of pain control
blocking ascending pathways (gate control theory)
blocking descending pathways (central biasing theory)
Release of beta endorphin and dynorphin
44
Pain modulation during and after TENS is achieved either through .......
gate control or opiate system
45
Gate control theory
activated by sensory TENS at higher frequency
46
Opiate system
activated by motor TENS and brief-intense TENS at lower frequency usually
47
```
Sensory level TENS (conventional, most used)
Used for....
Beat frequency...
Intensity....
Duration...
Electrode placement....
```
acute pain
high
tingling
short
directly over painful area, contiguous, dermatome, nerve root level
48
Motor level TENS used for...
Response is ....
Mechanisms...
subacute and chronic pain
not immediate but longer-lasting
central inhibition by descending pathways and opiate pain theory
49
```
Chronic pain application of TENS
Beat frequency...
Intensity...
Duration...
Time...
Electrode placement...
```
low
patient tolerance
long
over 45 min
target stimulation points
50
```
Brief-intense TENS-barely used
Used for...
Beat frequency....
Intensity....
Pain relief by....
```
chronic pain by stimulating c-fibers
varies between high and low and changes periodically
higher than sensory- burning, needling, twitch and tetanic muscle contractions
activating brain stem (negative feedback loop)
51
Contiguous electrode placement means
around painful site when painful site is contraindicated
52
IFC is ___ modulated
| Russian is ___ modulated
amplitude
time
53
IFC characteristics
two channels
medium frequency to decrease impedence of skin and deeper current flow
2000-5000 Hz
54
Three types of interference currents in IFC
constructive
destructive
continuous
55
Constructive interference
Destructive
Continuous
both waves are the same and produced in phase or originate at the same time-summative interference and amplitude is higher
waves are generated out of sync and cancel each other out the amplitude is lower
two currents with slightly different frequencies and will alternate between constructive and destructive
56
IFC and TENS produce similar waves but IFC
is capable of delivering a greater total current to the tissues
57
IFC produces ....
lower frequency effects at sufficient intensity and depth
58
Heterodyne effect=
blending of waves by constructive and destructive interference
59
Beat frequency is
difference between frequency of each channel
60
80-150 Hz for...
| 10-25 Hz for...
pain
muscle reed
61
Physiologic effects of IFC
| Therapeutic?
depolarize peripheral sensory or motor fibers
pain, blood flow, muscle contraction, edema management, spasm reduction
62
Pain control in IFC:
high beat frequencies (100 Hz)...
low beat frequencies (2-10 Hz)...
medium beat frequencies (15 Hz)....
sensory level=gate control
motor level= opiates
motor level= reduces edema using premodulated currents (muscle contractions with interrupted ouput)
63
Premodulated IF=
beat frequency and summation of currents occurs inside machine
bipolar method of delivery (2 medium frequency currents and 1 channel)
usually used when you cannot place 4 electrodes in an area
64
What is NMES?
| When is it used?
biphasic pulsed current
when there is muscle dysfunction due to a CNS lesion (CVA, spinal cord, TBI)
post-operative ortho
disuse atrophy
pain
65
Mechanoreceptor input is often altered when ...
ligaments and the capsule are sprained and the joint becomes unstable
66
Neuromuscular inhibition persists as long as ...
Swelling within the capsule may stimulate ...
capsule volume is elevated (Swelling)
stretch receptors which triggers reflex inhibition of the motor neuron pool.
67
NM control lost after sprains in ankle of which ligaments?
Hip?
Shoulder?
lateral ligaments
glute max
rotator cuff and scapula stability
68
NMES has ____ stimulation than other forms of electrical stimulation because it has a ____ duration and ___ amplitude.
Increase duration=
stronger
long phase
large
increases stimulation of pain fibers
69
In NMES, the amount of muscle torque that is produced is directly related to ...
amount of current introduced into the motor nerve
70
Alternating currents penetrate ...
deeper into tissues
71
E-stim depolarizes ____ nerves.
| Main goal is to elicit ....
alpha motor
strong muscle contraction through stimulation of those alpha motor nerves
72
With muscle Re-ed in NMES, which muscle fibers are being recruited? Why?
Type II
They have a larger cross-sectional area that provides less resistance to flow. They are also more superficial and receive greater stimulation.
73
When using NMES for muscle Re-ed, strengthening requires ___-___% of max voluntary force.
Endogenous contraction causes ____ fiber recruitment.
Exogenous causes___ recruitment.
40-60
slow twitch
fast twitch
74
Type of contraction depends on ___ ____ in NMES.
Low=
Medium=
High=
pulse frequency
under 15 pps individual muscle contraction
15-40 pps, summation of contractions increasing muscle tone
>40 pps, smooth tetanic (constant contraction
75
How to place electrodes in NMES for muscle contractions.
one electrode over motor point
on electrode on the muscle so current travels parallel to muscle fiber direction
place 2 in apart
76
```
Muscle strength settings:
pulse frequency:
on/off time:
intensity:
treatment time:
```
35-80 pps
10-15s on/ 50 sec-2 min off
strong, visible contraction
10-20 min, 3x a week
77
```
Muscle Re-ed settings:
Electrode placement:
pulse frequency:
on/off:
intensity:
treatment time:
```
bipolar on motor points and muscle belly
35-50pps
1:1-1:5
strong, visible contraction
15-20 min
78
NMES for edema reduction:
___-level.
Pulsed ___ current.
Decreases ___ and prevents fluids from escaping into interstitial space.
___-level for swelling reduction.
Muscular contractions encourage ___ and ___ return.
"____"
sensory
monophasic
permeability
motor
venous and lymphatic
milking
79
```
Edema reduction settings in NMES:
electrode placement:
pulse frequency:
on/off time:
intensity:
treatment time:
extremity should be...
```
bipolar on muscle group close to edema
35-50pps
2-5 seconds on/ 2-5 off
strong, visible, comfortable contraction
10-30 min, 2-5 times per day
elevated
80
Russian is used for...
It is a type of ___.
It is ___ modulated.
It is ___ and has a fast oscillating ___.
muscle re-ed and strengthening (more comfortable)
NMES
time
polyphasic, alternating current
81
Treatment regimens for Russian
10/50/10
10/10/10
82
Biofeedback muscle re-ed:
Intensity is ___
Set by having patient perform...
low
max isometric contraction of target muscle
83
Gain= ___ in biofeedback
sensitivity
84
Biofeedback for relaxation:
| Sensitivity is ...
high
85
EMG biofeedback uses how many electrodes?
3
86
Where are electrodes placed in biofeedback?
parallel to direction of muscle fibers and as close as possible to target muscle.
87
How does iontophoresis work?
electrostatic repulsion of like charges drives the medication in.
88
What current type is used to push the drug in?
direct
89
Since alkaline reaction is more caustic, the negative electrode should be ___ the size of postiive.
twice
90
What characteristics of drugs are used in iontophoresis?
ionic
stable in solution
ions are small or moderate in size
ions not altered by electric curretn
91
What is the most common steroid used in iontophoresis? What is its charge?
dexamethasone
negative
92
Lidocaine is what charge and used for?
positive and pain
93
Iontophoresis is commonly used for...
tennis elbow
achilles and patellar tendonitis
ITB
CTS
94
Treatment duration of iontophoresis?
| Dosage?
10-40 min
40mA*min
95
How long in between treatments should you wait for iontophoresis?
Positive results should be obtained within how many treatments?
24-48 hours
4-5 tx's
96
What is the most common problem with iontophoresis?
Why does this occur?
How an you minimize potential for this?
chemical burns
direct current
size of electrode, current intensity, changing electrode location between treatments
