Electrotherapy intro.. 5 th semester

ELECTROTHERAPY
 The use of electric currents passed through
the body to stimulate nerves and muscles,
chiefly in the treatment of various forms of
diseases.

CURRENTS
 Electric current:
 The movement or flow of charged
particles through a conductor in
response to an applied electric field
 Current is noted as I
 is measured in Amperes( A).

CURRENTS
 Conventional Current assumes that
current flows out of the positive terminal,
through the circuit and into the negative
terminal of the source. This was the
convention chosen during the discovery of
electricity.
 They were wrong!
 Electron Flow is what actually happens
and electrons flow out of the negative
terminal, through the circuit and into the
positive terminal of the source.

CURRENTS
 Charge: One of the basic properties of
matter ,which either has no charge( is
electrically neutral),
 or may be negatively (-)
 or positively (+) charged
 Charge Is noted as Q and is measured
in Coulombs( C).

CURRENTS
 Polarity:
 The property of having two oppositely
charged conductors, with the positive
called the anode, and the negative
called the cathode.
 in a conductor, free electrons flow from
an area of excess electrons( negative
pole) to an area deficient in electrons
( Positive Pole)

CURRENTS
 Voltage:
 The electrical force capable of moving
charged particles through a conductor
between two regions or points.
 Voltage is also known as the" potential
difference”
 Voltage is noted as V and is Measured
in volts (V)

CURRENTS
 FREQUENCY:
 frequency is the number of complete
cycles per second in alternating current
direction. The standard unit of frequency
is the hertz, abbreviated Hz.
 If a current completes one cycle per
second, then the frequency is 1 Hz;
 60 cycles per second equals 60 Hz

CURRENTS
 FREQUENCY;
 Larger units of frequency include the kilohertz
(kHz) representing thousands (1,000's) of
cycles per second, the megahertz (MHz)
representing millions (1,000,000's) of cycles
per second, and the gigahertz (GHz)
representing billions (1,000,000,000's) of
cycles per second. Occasionally the terahertz
(THz) is used; 1 THz = 1,000,000,000,000
cycles per second.

CURRENTS
 Direct Current (DC);
 A continuous unidirectional flow of
charged particles is known as direct
current (DC).
 Direct current is used to for
iontophoresis and for stimulating
contraction of denervated muscle and
also occasionally to facilitate wound
healing

CURRENTS
 Alternating Current (AC);
 A continuous bidirectional flow of
charged particles is known as
alternating current (A C)

CURRENTS
 Pulsed Current or Pulsatile Current:
Electrical current can be delivered
discontinuously in a series of pulses
separated by periods when no current
flows.
 This is known as pulsed or pulsatile
current.

CURRENTS
 A review on the differences…
 High Frequency Currents
 Medium Frequency Currents
 Low Frequency Currents

CURRENTS
 HIGH FREQUENCY CURRENTS
 •Frequency is >6000 H
 •Short wavelengths (<10 mm)
 •Effects occur only at superficial
structures
 •General effect = HEATING
 •Sample modalities:
 US, MWD, SWD, IRR, UVR, LASER

CURRENTS
 MEDIUM and LOW FREQUENCY
CURRENTS
 •Frequency ranges from 1 to 6000 Hz
 •Longer wavelengths (>10 mm)
 •Effects occur at deeper structures
 •General effects:
 MFC: blocks pain
 LFC: nerve stimulation

CURRENTS
 MEDIUM and LOW FREQUENCY
CURRENTS
 •Sample modalities:
 •Electrical stimulators, Diadynamics,
Biofeedback, Iontophoresis, TENS, IF,
Faradic.

CURRENTS
:
 LOW FREQUENCY CURRENT
 MEDIUM FREQUENCY CURRENT

CURRENTS
 LOW FREQUENCY CURRENT:
 It includes;
 Faradic current.
 Sinusoidal current.
 Galvanic current.
 Superimposed currents.
 TENS.
 Dia-dynamic currents.

CURRENTS
 MEDIUM FREQUENCY CURRENTS:
 INTERFRENTIAL CURRENT.

Electrotherapy defined by
Frequency
SWD,
MWD,
IRR,
UVR, US
Interferential
therapy,
TENS
Sinusoidal,
faradic
currents
Modalities
ThermalPain
inhibition
Motor and
sensory
stimulation
Effect
+Motor
stimulation
+Sensory
stimulation
>500,000
Hz
3000-6000 Hz1-2000 HzFrequency
HFC’sMFC’sLFC’s

FARADIC CURRENT
 Faradic current is a short-duration
interrupted current, with a pulse duration
ranging from 0.1 and 1 msec and a
frequency of 50 to 100 Hz.

FARADIC CURRENT
 The waveform of faradic-type current
may be unidirectional or biphasic
(asymmetrical)

FARADIC CURRENT
 Faradic currents are always surged for
treatment purposes to produce a near normal
tetanic-like contraction and relaxation of
muscle. Current surging means the gradual
increase and decrease of the peak intensity

FARADIC CURRENT
 Forms of faradic current:
 Each represents one impulse:
 * In surged currents, the intensity of the
successive impulses increases
gradually, each impulse reaching a peak
value greater than the preceding one
then falls either suddenly or gradually.

FARADIC CURRENT
 * Surges can be adjusted from 2 to 5-
second surge, continuously or by
regularly selecting frequencies from 6 to
30 surges / minute.
 * Rest period (pause duration) should be
at least 2 to 3 times as long as that of
the pulse to give the muscle the
sufficient time to recover (regain its
normal state).

FARADIC CURRENT
 * The most comfortable pulse is either
0.1-msec pulse, with a frequency of 70
Hz or 1-msec pulse with a frequency of
50 Hz.

Physiological effects of
faradic current:
 1. Stimulation of sensory nerves: It is not
very marked because of the short
duration. It causes reflex vasodilatation
of the superficial blood vessels leading
to slight erythema. The vasodilatation
occurs only in the superficial tissues.

faradic current:
 2. Stimulation of the motor nerves:
 It occurs if the current is of a sufficient
intensity, causing contraction of the
muscles supplied by the nerve distal to
the point of stimulus. A suitable faradic
current applied to the muscle elicits a
contraction of the muscle itself and may
also spread to the neighboring muscles.

faradic current:
 The character of the response varies
with the nature and strength of the
stimulus employed and the normal or
pathological state of muscle and
nerve….

faradic current:
 .. The contraction is tetanic in type
because the stimulus is repeated 50
times or more / sec; if this type is
maintained for more than a short time,
muscle fatigue occurs. So, the current is
commonly surged to allow for muscle
relaxation i.e. “when the current is
surged, the contraction gradually
increases and decreases in strength in a
manner similar to voluntary contraction”.

faradic current:

faradic current:
 3. Stimulation of the nerve is due to
producing a change in the semi-
permeability of the cell membrane: This
is achieved by altering the resting
membrane potential. When it reaches a
critical excitatory level, the muscle
supplied by this nerve is activated to
contract.

faradic current:
 4. Faradic currents will not stimulate
denervated muscle: The nerve supply to
the muscle being treated must be intact
because the intensity of current needed
to depolarize the muscle membrane is
too great to be comfortably tolerated by
the patient in the absence of the nerve.

faradic current:
 5. Reduction of swelling and pain: It
occurs due to alteration of the
permeability of the cell membrane,
leading to acceleration of fluid
movement in the swollen tissue and
arterial dilatation. Moreover, it leads to
increase metabolism and get red of
waste products.

FARADIC CURRENT
 Indications:
 1. Facilitation of muscle contraction
inhibited by pain: Stimulation must be
stopped when good voluntary
contraction is obtained.

FARADIC CURRENT
 2. Muscle re-education: Muscle
contraction is needed to restore the
sense of movement in cases of
prolonged disuse or incorrect use; and
in muscle transplantation. The brain
appreciates movement not muscle
actions, so the current should be applied
to cause the movement that the patient
is unable to perform voluntarily.

FARADIC CURRENT
 3. Training a new muscle action: After
tendon transplantation, muscle may be
required to perform a different action
from that previously carried out. With
stimulation by faradic current, the patient
must concentrate with the new action
and assist with voluntary contraction.

FARADIC CURRENT
 4. When a nerve is severed,
degeneration of the axons takes place
after several days. So, for a few days
after the injury, the muscle contraction
may be obtained with faradic current. It
should be used to exercise the muscle
as long as a good response is present
but must be replaced by modified direct
current as soon as the response begins
to weaken.

Faradic current
 5. Improvement of venous and lymphatic
drainage: In edema and gravitational
ulcers, the venous and lymphatic return
should be encouraged by the pumping
action of the alternate muscle
contraction and relaxation.

Faradic current:
 6. Prevention and loosening of
adhesions: After effusion, adhesions are
liable to form, which can be prevented
by keeping structures moving with
respect to each other. Formed
adhesions may be stretched and
loosened by muscle contraction.

Faradic current:
 7. Painful knee syndromes: After
trauma, there is inhibition of muscle
contraction, leading to muscle atrophy.
For example, after knee surgery e.g.
menisectomy, there should be no gross
effusion of the knee as it causes
difficulty in obtaining the motor point of
the muscles.

Faradic current:
 8. Inhibition of quadriceps contraction by
pain: As in rheumatoid arthritis,
subluxation of patella, chondromalicia
patellae and chronic effusion of the
knee.

Faradic current:
 Contraindications:
 * Skin lesions: The current collects at
that point causing pain.
 * Certain dermatological conditions:
Such as psoriasis, tinea and eczema.
 * Acute infections and inflammations.
 * Thrombosis.
 * Loss of sensation.

Faradic current:
 * Cancer.
 * Cardiac pacemakers.
 * Superficial metals

FARADIC CURRENT
 The mechanism of pain inhibition and
muscle spasm:
 Pain has an inhibitory effect on the large
anterior horn cells. Stimulation of the
afferent nerve fibers decreases this
inhibition and influences the alpha motor
neurons. Subsequently, facilitation of
transmission of impulses to the extrafusal
fibers follows with inhibition of the
antagonists, allowing a more natural
sequence of movements.

FARADIC CURRENT
 Controlled muscle contraction:
 Controlled muscle contraction results from:
 * Excitation of the small efferent fibers,
which cause contraction of the intrafusal
fibers.
 * Stretching of muscle spindle, which sends
information to the anterior horn cells,
recruiting the motor unit, leading to muscle
contraction.

FARADIC CURRENT
 Methods of application of faradic current:
 Electrical muscle stimulation is usually
achieved by faradic-type currents (0.1—1
ms duration at any frequency between 30
and 100Hz).
 In order to localize the current to individual
muscles a small active electrode, i.e. a
small pad or button electrode, is applied to
the motor point of the muscle,

FARADIC CURRENT
 the circuit being completed
 with a larger dispersive electrode sited
in some convenient, usually proximal,
area.
 The motor points of some superficial
muscles are often indicated on charts
Such charts act as a guide but a
knowledge of the relevant anatomy
coupled with that.

FARADIC CURRENT
 little trial and error will locate the precise point
at which the muscle is most effectively
stimulated.
 The usual site is in the lower part of the
proximal third of the muscle belly but there are
many exceptions.
 It is obvious that deeply placed muscles can
only be successfully stimulated where their
fleshy belly emerges, for example, the
extensor hallucis longus emerging in the lower
part of the leg between tibialis anterior and
extensor digitorum longus.

FARADIC CURRENT
 As mentioned previously, if a choice is a liable,
constant current pulses are preferred for
techniques in which the pads are fixed,
because they are reputed to be more
comfortable.
 However, for labile techniques, where one pad
is moved, constant voltage is preferable. In
these applications, the effective area (i.e. the
area in contact with the skin) of the
pad/electrode changes, which alters the
current density. If the area of the pad in
contact with the tissues becomes smaller, the
resistance increases.

FARADIC CURRENT
 Technique of application:
 The patient is positioned so that the part
to be treated is comfortably supported
with the muscles to be stimulated in a
shortened position, although this may be
modified when movement is to be
produced, e.g. slight knee flexion
allowing quadriceps stimulation to cause
extension.

FARADIC CURRENT
 The skin surfaces to which the current
will be applied must be examined and
any cuts, abrasions or other lesions that
might cause uneven current distribution
insulated (with a dab of petroleum jelly)
or avoided. These areas should be
washed to remove sebum and epithelial
cells and left damp; using hot water
warms the skin and helps to lower the
resistance further.

FARADIC CURRENT
 The size of the active electrode, which may
be a small plate and pad or a button
electrode, is chosen by considering the
size of the area to be treated.
 The motor point of a small muscle close to
others is clearly best stimulated with a
small button electrode. In all cases the
dispersive or indifferent pad should be two
or three times larger. 1eads are connected
to the machine and attached to the
electrodes.

FARADIC CURRENT
 The metal electrode should be smaller than
the pad or sponge material to prevent the
edge of the electrode being bent down on to
the skin which could lead to high current
density at that point and would be very
uncomfortable.
 Holding the two electrodes, separated, in one
hand allows the machine and connections to
be tested by the therapist. Observing this may
help to allay(decrease intensity and emotions)
the anxiety of a patient experiencing this
treatment for the first time.

FARADIC CURRENT
 The pads or sponges should be soaked in
warm tap water, saline or sodium
bicarbonate solution, which are somewhat
better conductors, particularly in soft water
areas, and applied to the skin.
 Fixation is achieved with a rubber strap, a
crêpe or similar bandage, or simply by
body weight. A piece of polythene or other
waterproof material is placed on the pad to
prevent the bandage becoming wet. If the
whole bandage gets wet, it becomes
effectively a circular pad.

FARADIC CURRENT
 The nature of the treatment and the
sensations to be expected — a tingling
sensation and muscle contraction —
should be explained to the patient with
reassurance that there is no way that any
damage can be caused by this treatment.
 When a single muscle is to be stimulated
the active electrode is placed firmly over
the approximate motor point, indicated in

FARADIC CURRENT
 and a small current is applied.
 Small adjustments of the position of the
active electrode will allow the best
position to be found; the current may
need to be increased and then
decreased as the exact motor point is
found and good contractions can be
obtained with less current.

FARADIC CURRENT
 When a muscLe group is to be
stimulated the active pad can be made
to straddle all the motor points or the
two pads may be of approximately the
same size, placed at either end of the
muscle group so that current spreads
through the whole group.

FARADIC CURRENT
 The stimulation of individual muscles is
often done to re-educate the activity.
 In this case the patient attempts a
voluntary contraction at the same time
as the current causes the muscle to
contract.

FARADIC CURRENT
……to enable the patient to co-operate,
the length of the contractions and the
intervals between them should be
suitably long.
 This allows patients time to match their
efforts with the stimulated contractions
and an adequate rest between each
one.

FARADIC CURRENT
 EXAMPLE:
 Wrist drop, also known as radial nerve
palsy, or Saturday night palsy, is a
condition where a person cannot extend
their wrist and it hangs flaccidly.

FARADIC CURRENT
 For treatment purpose one electrode
(anode) is placed over trunk(behind
trapezius or near common extensor
tendon…
 The active electrode (cathode) is placed
at motor point (posterior surface of
forearm…
 While increasing intensity muscle will
produce contraction so help in training of
paralyzed muscle.

FARADIC CURRENT
 Re-educating the pelvic floor musculature for
the treatment of stress incontinence requires a
special technique to stimulate the sphincter
muscles of the urethra.
 This can be done with a large dispersive over
the lumbosacral region and a rectal electrode
as the active with the patient in side-lying or in
crook half-lying.
 In females a vaginal electrode can be used; a
button electrode placed over the perineal body
can be used as the active electrode in either
Male/Female

FARADIC CURRENT
 Voluntary contraction is attempted with
the electrical stimulation.
 Faradic type currents have been used in
the successful treatment of this
condition.

FARADIC CURRENT
 Muscle groups in the limbs can be
stimulated rhythmically to effect a muscle
pumping action, enhancing the venous and
lymphatic flow to assist the reduction of
edema.
 This is combined with elevation of the limb
and the application of a pressure bandage.
 The largest volume of muscle that can be
stimulated is required, so the quadriceps
and plantar flexors of the lower limb and
flexors of the elbow and hand in the upper
limb are usually chosen

FARADIC CURRENT
 Large pads are applied over these muscle
groups, or on the sole of the foot and
quadriceps; there are numerous other pad
positions to achieve the strong generalized
muscle contractions needed. The
compression bandage, applied over the
pads, should give firm pressure against
which the contracting musculature can
press but should not be constrictive.
 Strong slow muscle contractions should be
produced with a long period of relaxation
(several seconds) to allow vessel filling

FARADIC CURRENT
 Clinical Uses of Faradic-type Current
 •Faradic-type current is still frequently
applied in the form of functional
electrical stimulation (FES). In this
technique the application of the faradic
current is combined with the patient
activity.

FARADIC CURRENT
 •1. Facilitation of muscle contraction
inhibited by pain like post operative or
post-traumatic inability to achieve
voluntary contraction of certain muscles.
 •2. Early stage of muscle re-innervation.

FARADIC CURRENT
 •3. Treatment of hysterical paralysis
(without loss of reflex
activity/psychogenic)
 •4. Treatment of atrophied and weak
muscles following long duration
immobilization.

FARADIC CURRENT
 5. Treatment of muscle imbalance as in
faulty posture (flat foot and scoliosis).
 •NOTE: Faradic-type currents never
used to stimulate denervated
muscles.

FARADIC CURRENT
 Contraindications
 1- Skin lesions as cuts and abrasions to
avoid the difference of skin resistance
which may lead to more concentration of
current on some points especially under
electrodes causing discomfort and pain.
 2- Cardiac pacemaker

FARADIC CURRENT
 Contraindications
 •3- Infection to avoid spread of
infection by low frequency current.
 •4- Superficial metal to avoid
concentration of current on metal and
cause burn.

Electrotherapy intro.. 5 th semester

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Electrotherapy intro.. 5 th semester