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2
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- Creating muscle contraction through nerve or muscle stimulation
- Stimulating sensory nerves to help in treating pain
- Creating an electrical field in biologic tissues to stimulate or alter
the healing process
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3
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- Creating an electrical field on the skin surface to drive ions
beneficial to the healing process into or through the skin
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4
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- As electricity moves through the
body's conductive medium, changes in the physiologic functioning can
occur at various levels
- Cellular
- Tissue
- Segmental
- Systematic
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5
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- Excitation of nerve cells
- Changes in cell membrane permeability
- Protein synthesis
- Stimulation of fibrobloast, osteoblast
- Modification of microcirculation
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- Skeletal muscle contraction
- Smooth muscle contraction
- Tissue regeneration
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- Modification of joint mobility
- Muscle pumping action to change circulation and lymphatic activity
- Alteration of the microvascular system not associated with muscle
pumping
- Increased movement of charged proteins into the lymphatic channels
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8
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- Transcutaneous electrical stimulation cannot directly stimulate lymph
smooth muscle, or the autonomic nervous system without also stimulating
a motor nerve
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9
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- Analgesic effects as endongenous pain suppressors are released and act
at different levels to control pain
- Analgesic effects from the stimulation of certain neurotransmitters to
control neural activity in the presence of pain stimuli
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10
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- Effects may be direct or indirect
- Direct effects occur along lines of current flow and under electrodes
- Indirect effects occur remote to area of current flow and are usually
the result of stimulating a natural physiologic event to occur
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11
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- Excitability dependent on cell membrane's voltage sensitive permeability
- Produces unequal distribution of charged ions on each side of the
membrane
- creates a potential difference between the charge of the interior of
cell and exterior of cell
- Potential difference is known as resting potential because cell tries to
maintain electrochemical gradient as its normal homeostatic environment
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12
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- Using active transport mechanism-cell continually moves Na+ from inside
cell to outside and balances this positive charge movement by moving K+
to the inside
- Produces an electrical gradient
with + charges outside and - charges inside
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13
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- To create transmission of an impulse in nerve, resting membrane
potential must be reduced below threshold level
- Changes in membrane's permeability may then occur creating an action
potential that propagates impulse along nerve in both directions causing
depolarization of membrane
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14
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- Stimulus must have adequate intensity and last long enough to equal or
exceed membrane's basic threshold for excitation
- Stimulus must alter membrane so that a number of ions are pushed across
membrane exceeding ability of the active transport pumps to maintain the
resting potentials thus forcing
membrane to depolarize resulting in an action potential
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15
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- Difference in electrical potential between depolarized region and
neighboring inactive regions causes the current to flow from depolarized
region intercellular material to the inactive membrane
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- Current also flows through extracellular materials, back to the
depolarized area, and finally into cell again
- Makes depolarization self propagating as process is repeated all along
fiber in each direction from depolarization site.
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- As nerve impulse reaches effector organ or another nerve cell, impulse
is transferred between the two at a motor end plate or a synapse
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- At this junction, a transmitter substance is released from nerve
- Transmitter substance causes the other excitable tissue to discharge
causing a twitch muscle contraction
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19
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- Represents The Threshold for Depolarization of a Nerve Fiber
- Muscle and nerve respond in an
all-or-none fashion and there is no gradation of response
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20
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- Shape of the curve relates intensity of electrical stimulus (strength)
and length of time (duration) necessary to cause the tissue to
depolarize
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21
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- Rheobase describes minimum intensity of current necessary to cause
tissue excitation when applied for a maximum duration
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22
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- Chronaxie describes length of time (duration) required for a current of
twice the intensity of the rheobase current to produce tissue excitation
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23
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- Aß sensory, motor, Ad sensory,
and C pain nerve fibers
- Durations of several electrical
stimulators are indicated along the lower axis
- Corresponding intensities would be necessary to create a depolarizing
stimulus for any of the nerve fibers
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24
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- Alternating versus direct current
- Tissue impedance
- Current density
- Frequency of wave or pulse
- Intensity of wave or pulse
- Duration of wave or pulse
- Polarity of electrodes
- Electrode placement
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25
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- Nerve doesn’t know the difference between AC and DC
- With continuous direct current a muscle contraction would occur only
when the current intensity rose to a stimulus threshold
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26
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- Once the membrane repolarized, another change in the current intensity
would be needed to force another depolarization and contraction
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27
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- Biggest difference in effects of alternating and direct currents is
ability of direct current to cause chemical changes
- Chemical effects from using
direct current usually occur only when stimulus is continuous and is
applied over a period of time
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28
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- Impedance -resistance of the
tissue to the passage of electrical current.
- Bone and fat are high-impedance tissues; nerve and muscle are
low-impedance
- If a low-impedance tissue is located under a large amount of
high-impedance tissue current will never become high enough to cause a
depolarization
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29
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- Current Density- - Refers To The Volume Of Current In The Tissues
- Highest At Surface And Diminishes In Deeper Tissue
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30
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- Change The Spacing Of Electrodes
- Moving Further Apart Increases Current Density In Deeper Tissues
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31
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- Changing The Size Of The Electrode
- Active Electrode Is The Smaller of The Two
- Current Density Is Greater
- Dispersive Electrode Is The Larger
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32
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- Effects the type of muscle contraction
- Effects the mechanism of pain modulation
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33
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- Increasing the intensity of the electrical stimulus causes the current
to reach deeper into the tissue
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34
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- A stimulus pulse at a duration-intensity just above threshold will
excite the closest and largest fibers
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35
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- Increasing the intensity will excite smaller fibers and fibers farther
away. C, Increasing the duration will also excite smaller fibers and
fibers farther away.
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36
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- We also can stimulate more nerve fibers with the same intensity current
by increasing the length of time (duration) that an adequate stimulus is
available to depolarize the membranes
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37
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- Anode
- Positive Electrode With Lowest Concentration of Electrons
- Cathode
- Negative Electrode With Greatest Concentration of Electrons
- Polarity Switch Designates One Electrode As Positive and One As Negative
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38
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- With AC Current and Interrupted DC Current Polarity Is Not Critical
- Select Negative Polarity For Muscle Contraction
- Facilitates Membrane Depolarization
- Usually Considered More Comfortable
- Negative Electrode Is Usually Positioned Distally
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- Negative Pole
- Attracts + Ions
- Alkaline Reaction
- Softening of Tissues
- Increased Nerve Irritability
- Important Consideration When Using Iontophoresis
- Positive Pole
- Attracts - Ions
- Acidic Reaction
- Hardening of Tissues
- Decreased Nerve
Irritability
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40
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- Electrodes may be placed:
- On or around the painful area
- Over specific dermatomes, myotomes, or sclerotomes that correspond to
the painful area
- Close to spinal cord segment that innervates an area that is painful
- Over sites where peripheral nerves that innervate the painful area
becomes superficial and can be easily stimulated
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41
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- Electrodes may be placed:
- Over superficial vascular structures
- Over trigger point locations
- Over acupuncture points
- In a criss-cross pattern around the point to be stimulated so the area
to be treated is central to the location of the electrodes
- If treatment is not working- change placement
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42
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- Muscle reeducation
- Muscle pump contractions
- Retardation of atrophy
- Muscle strengthening
- Increasing range of motion
- Reducing Edema
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43
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- Muscular inhibition after surgery or injury is primary indication
- A muscle contraction usually can be forced by electrically stimulating
the muscle
- Patient feels the muscle contract, sees the muscle contract, and can
attempt to duplicate this muscular response
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44
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- Current intensity must be adequate for muscle contraction but
comfortable
- Pulse duration must be set as close as possible to the duration needed
for chronaxie of the tissue to be stimulated
- Pulses per second should be high enough to give a tetanic contraction
(20 to 40 pps)
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45
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- Interrupted or surged current must be used
- High-voltage pulsed or medium-frequency alternating current may be most
effective
- On time should be 1 to 2 seconds
- Off time should be 4 to 10 seconds
- Total treatment time should be about 15 minutes, repeated several times
daily
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46
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- Patient should be instructed to allow just the electricity to make the
muscle contract, feeling and seeing the response desired
- Next, patient should alternate voluntary muscle contractions with
current-induced contractions
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47
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- Used to duplicate the regular muscle contractions that help stimulate
circulation by pumping fluid and blood through venous and lymphatic
channels back to the heart
- Can help in reestablishing proper circulatory pattern while keeping
injured part protected
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48
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- Current intensity must be high enough to provide a strong,
comfortable muscle contraction
- Pulse duration should be set as close as possible to the duration needed
for chronaxie of the motor nerve to be stimulated if not preset
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49
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- Pulses per second should be at beginning of tetany range (20 pps).
- Interrupted or surged current must be used
- On time should be 5 to 10 seconds.
- Off time should be 5 to 10 seconds.
- The part to be treated should be elevated
- Total treatment time should be 20
to 30 minutesrepeated two to five times daily
- 8. The athlete should be instructed to allow the electricity to make the
muscles contract. Active range of motion may be encouraged at the same
time if it is not contraindicated.
- 9. 10. High-voltage pulsed or medium-frequency alternating current may
be most effective.32,39,94,97,111 (See Fig. 5-20).
- 11. Use this protocol in addition to the normal I.C.E. for best
effect.41,88
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50
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- High-voltage pulsed or medium-frequency alternating current may be most
effective
- Athlete should be instructed to allow the electricity to make the
muscles contract.
- Active range of motion may be encouraged at the same time if it is not
contraindicated
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51
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- Electrical stimulation reproduces physical and chemical events
associated with normal voluntary muscle contraction and helps to
maintain normal muscle function
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52
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- Current intensity should be as high as can be tolerated
- Contraction should be capable of moving the limb through the antigravity
range or of achieving 25% or more of the normal maximum voluntary
isometric contraction (MVIC) torque for the muscle
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53
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- Pulse duration should be set as close as possible to the duration needed
for chronaxie of the motor nerve to be stimulated
- Pulses per second should be in the tetany range (20 to 85 pps)
- Interrupted or surge type current should be used
- Medium-frequency alternating current stimulator is the machine of choice
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54
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- On time should be between 6 and 15 seconds
- Off time should be at least one
minute preferably two minutes.
- Muscle should be given some resistance, either gravity or external
resistance provided by the addition of weights or by fixing the joint so
that the contraction becomes isometric
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55
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- Patient can be instructed to work with electrically induced contraction,
but voluntary effort is not necessary
- Total treatment time should be 15 to 20 minutes, or enough time to allow
a minimum of 10 contractions
- Treatment can be repeated two times daily
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56
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- Current intensity should make muscle develop 60% of torque developed in
a maximum voluntary isometric contraction (MVIC)
- Pulse duration should be set as close as possible to the duration needed
for chronaxie of the motor nerve to be stimulated
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57
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- Pulses per second should be in the tetany range (20 –85 pps)
- Surged or interrupted current with a gradual ramp to peak intensity most
effective
- On time should be 10-15 seconds
- Off time should be 50 seconds to 2 minutes
- Medium-frequency alternating current stimulator is machine of choice
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58
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- Muscle is given an isometric contraction torque equal to or greater than
25% of the MVIC torque
- Patient instructed to work with the electrically induced contraction,
but voluntary effort is not necessary
- Total treatment should mimick normal active resistive training protocols
of 3 sets of 10 contractions
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59
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- Electrically stimulating a muscle contraction pulls joint through
limited range
- Continued contraction of muscle group over extended time appears to make
contracted joint and muscle tissue modify and lengthen
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60
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- Current intensity must be of sufficient intensity and duration to make
muscle contract strongly enough to move the body part through
antigravity range
- Pulse duration should be set as close as possible to the duration needed
for chronaxie of the motor nerve to be stimulated
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61
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- Pulses per second should be at the beginning of the tetany range (20 to
30 pps)
- Interrupted or surged current should be used
- On time should be between 15 and 20 secs
- Off time should be equal to or
greater than on time, fatigue is a big consideration
- High-voltage pulsed or medium-frequency alternating current stimulators
are suggested
- The stimulated muscle group should be antagonistic to the joint
contracture and the athlete should be positioned so the joint will be
moved to the limits of the available range.
- 8. The athlete is passive in this treatment and does not work with the
electrical contraction.
- 9. Total treatment time should be 90 minutes daily. This can be broken
into three 30-minute treatments.
- 10..
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- Stimulated muscle group should be antagonistic to joint contracture and
patient should be positioned so joint will be moved to the limits of
available range
- Patient is passive in treatment and does not work with electrical
contraction
- Total treatment time should be 90 minutes daily broken into 3 x
30-minute treatments
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63
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- Sensory level direct current used as a driving force to make charged
plasma protein ions in interstitial spaces move in the direction of
oppositely charged electrode
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64
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- Current intensity should be (30V-50V) or 10% less than needed to produce
a visible muscle contraction
- Preset short duration interrupted DC currents with high pulse
frequencies (120 pps) on high voltage equipment are effective
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65
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- Distal electrode should be negative
- Treatment should begin immediately after injury
- Thirty minute treatment showed good control of volume for 4 to 5 hours
- High voltage pulsed generators are effective, low voltage generators are
not effective
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66
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- Electrical currents may be used to produce a muscle contraction in
denervated muscle
- Denervated muscle has lost its peripheral nerve supply
- Purpose for electrically stimulating denervated muscle is to help
minimize the extent of atrophy while the nerve is regenerating
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67
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- Muscle fibers experience a decrease in size, diameter and weight of the
individual muscle fibers
- There is a decrease in amount of tension which can be generated and an
increase in the time required for contraction
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68
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- Degenerative changes progress until muscle is reinnervated by axons
regenerating across site of lesion
- If reinnervation does not occur
within 2 years fibrous connective tissue replaces contractile elements
and recovery of muscle function is not possible
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69
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- A current with an asymmetric, biphasic (faradic)waveform pulse duration <
1 ms may be used during the first 2 weeks
- After 2 weeks, either an interrupted DC square wave or a progressive DC
exponential wave with long pulse duration > 10 ms, or a AC sine wave
with frequency < 10 Hz will produce a twitch contraction
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70
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- Length of pulse should be as short as possible but long enough to elicit
a contraction
- Current waveform should have pulse duration = or > than chronaxie of
denervated muscle
- Amplitude of current along with pulse duration must be sufficient to
stimulate a denervated muscle with a prolonged chronaxie while producing
a moderately strong contraction of muscle fibers
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71
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- Pause between stimuli should be 4 to 5 times longer (about 3-6 seconds)
than stimulus duration to minimize fatigue
- Either a monopolar or bipolar electrode setup can be used with small
diameter active electrode placed over most electrically active point
- Stimulation should begin
immediately using 3 sets of 5
-20 repetitions 3 x per day
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72
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- Gate Control Theory
- Descending Pain Control
- Opiate Pain Control
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73
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- Current intensity adjusted to tolerance but should not cause muscular
contraction
- Pulse duration should be 75 -150 µsec or maximum possible
- Pulses per second should be 80-125 or as high as possible
- A transcutaneous electrical stimulator waveform should be used
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74
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- Continuous on time should be used
- Total treatment time should correspond to fluctuations in pain;
- Unit should be left on until pain is no longer perceived, turned off,
then restarted when pain begins again
- Should have positive result in 30 min. if not reposition electrodes
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75
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- Current intensity should be very high, approaching noxious level
- Pulse duration should be 10 msec.
- Pulses per second should be 80.
- On time should be 30 seconds to 1 minute
- Stimulation should be applied over trigger or acupuncture points
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76
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- Selection and number of points used varies according to the part
treated.
- Low-frequency,high-intensity generator is stimulator of choice for
central biasing
- Should have positive result shortly after treatment begins-if not
reposition electrodes
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77
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- Current intensity should be high, at a noxious level- muscular
contraction is acceptable
- Pulse duration should be 200 µsec to 10 msec
- Pulses per second should be 1-5.
- High-voltage pulsed current should be used.
- On time should be 30 to 45 seconds.
- Stimulation should be applied over trigger or acupuncture points
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78
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- Selection and number of points used varies according to part and
condition being treated
- High-voltage pulsed current or a low-frequency, high-intensity machine
is best
- Analgesic effect should last for several (6-7) hours
- If not successful, try expanding the number of stimulation sites
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79
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- Medical Galvinism
- Ionotphoresis
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80
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- Continuous low-volt direct current causes:
- Polar effects
- Acid reaction around the positive pole and the alkaline reaction at
the negative pole
- Acidic or alkaline changes can cause severe skin reactions
- Occur only with low-voltage continuous direct current and are not
likely with the high-voltage generators since current duration is too
short to cause chemical changes
- Vasomotor Changes
- Blood flow increases between the electrodes.
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81
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- Current intensity should be to tolerance
- Intensity in the milliamp range.
- Continuous direct current should be used
- Pulses per second should be 0.
- Low-voltage direct current stimulator is the machine of choice.
- Treatment time should be between 15-50 min
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82
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- Equal-sized electrodes are used over gauze that has been soaked in
saline solution and lightly squeezed
- Skin should be unbroken
- Skin burns are the greatest hazard of any continuous direct current
technique
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83
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- FES utilizes multiple channel electrical stimulators controlled by a
microprocessor to recruit muscles in a programmed synergystic sequence
that will allow patient to accomplish a specific functional movement
pattern
- Multichannel microprocessors may be pre-programmed to execute a variety
of specific movement patterns
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84
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- Originally called microcurrent electrical neuromuscular stimulators
(MENS)
- LIS currents are not substantially different from the currents discussed
previously
- LIS generators produce current where intensity is limited to <1000
microamps (1 milliamp) while intensity of standard low-voltage equipment
can be increased into milliamp range
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85
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- Low intensity stimulation has been used for two major effects:
- Analgesia of the painful area
- Biostimulation of the healing process either for enhancing the process
or for acceleration of its stages
- Used to promote wound healing (skin ulcers) and fracture healing
(nonunion
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86
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- LIS is a subsensory current
- As such it does not fit existing models of pain modulation
- Exact mechanism of action has not yet been established
- LIS can create or change constant direct current flow of the neural
tissues which may have some way of biasing transmission of painful
stimulus
- May also make nerve cell membrane more receptive to neurotransmitters
which will block transmission
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87
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- Low intensity stimulators can be used but other generators with
intensities adjusted to sub-sensory levels can also be effective
- Current intensity is 200-400 µamp for normal skin and 400-800 µamp for
denervated skin
- Long pulse durations or continuous uninterrupted currents can be used
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88
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- Maximum pulse frequency
- Monophasic direct current is best but biphasic direct current is
acceptable. A battery powered portable unit is most convenient.
- Treatment time 2 hours followed by a 4 hour rest time
- 2-3 treatment bouts per day
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89
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- Negative electrode positioned in the wound area for the first 3 days
- Positive electrode positioned 25 cm proximal to the wound
- After 3 days polarity reversed and positive electrode is positioned in
the wound area
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90
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- With infection negative electrode should be left in wound area until the
signs of infection are not evident and for 3 more days after infection
clears
- If wound size decrease plateaus return the negative electrode to the
wound area for 3 days
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91
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- Current intensity is just perceptible to patient
- Pulse duration is longest duration allowed on unit (100 to 200 msec)
- Pulses per second set at lowest frequency allowed on unit (5 to 10 pps)
- Standard monophasic or biphasic current in TENS units used
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92
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- Treatment time 30 minutes-1 hour 3-4 x daily
- Negative electrode placed close to but distal to fracture site
- Positive electrode placed proximal to immobilizing device
- Results reassessed at monthly intervals
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93
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- Deliver medium (2000 -10,000 Hz) frequency polyphasic AC wave form
- Pulse varies from 50-250 µsec; the phase duration is half of the pulse
duration or 25-125 µsec
- Two basic waveforms: sine wave or
square wave cycles with a fixed intrapulse interval
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94
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- Sine wave produced in burst mode with 50% duty cycle
- To make intensity of current tolerable it is generated in
50-burst-per-second envelopes with an interburst interval of 10 msec
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95
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- Dark shaded area represents total current, and light shading indicates
total current without the interburst interval
- When generated with burst effect total current is decreased allowing for
tolerance of greater current intensity
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96
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- Higher frequency currents reduce resistance to current flow making wave
form comfortable enough to tolerate higher intensities
- As intensity increases more motor nerves are stimulated increasing
magnitude of the contraction
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97
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- Because it is a fast oscillating AC current, as soon as nerve
repolarizes it is stimulated again, producing a current that will
maximally summate muscle contraction
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98
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- Make use of 2 separate generators
- Produce sine waves at different frequencies
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99
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- When displayed on an oscilloscope with only one generator the current
behaves as previously described
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100
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- If a second generator is added the currents may interfere with each
other
- If produced in phase if or they originate at same time interference can
be summative-amplitudes of the electric wave are combined and increase
- Referred to as constructive interference
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101
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- If waves are generated out of sync, Generator 1 starts in a positive
direction at the same time that Generator 2 starts in a negative
direction- waves cancel each other out
- Referred to as destructive interference
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102
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- If two generators have slightly different frequencies they are out of
phase an thus create a beat pattern
- Blending of waves caused by constructive and destructive interference
patterns called heterodyne effect
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103
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- When using an interference current
- Set intensity according to peak
- Select the frequencies to create a beat frequency corresponding to
choices of frequency when using other stimulators
- 20 to 50 pps for muscle contraction
- 50 to 120 pps for pain management
- 1 pps for acustim pain relief
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104
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- When electrodes are arranged in a square and interferential currents are
passed through a homogeneous medium a predictable pattern of
interference will occur
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105
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- An electric field is created where two currents cross between lines of
electric current flow
- Maximum interference effect takes place near center, with field
gradually decreasing in strength as it moves away from center
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106
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- Scanning interferential current moves force around while the treatment
is taking place enlarging effective treatment area
- Another set of electrodes create a three-dimensional flower effect
called a stereodynamic effect
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