Faradic current

1st muscle stimulating current
used in medicine
 An uneven AC with pulse duration
of 0.1-1ms & frequency of 30 to
100 Hz

Waveform-
Biphasic, asymmetrical,
unbalanced, spiked
Positive portion – Short
duration, high amplitude
and spiked
Negative portion – Long
duration, low amplitude
and curved

 Short duration interrupted DC with pulse
duration of 0.02-1ms and frequency of 50Hz.
 Modifications-
 These currents are always surged for treatment
purposes to produce a near normal tetanic-like
contraction & relaxation of muscle
 Current is surged at variable controlled speed
ranging from 30 to 40 surges/min with varying rest
period

Trapezoidal Surging:
Impulses increases slowly,
maintained there for sometime &
decreases gradually forming
trapezoidal shape
Triangular Surging:
Impulses increases & decreases
gradually forming
triangular shape

Saw-tooth:
Impulses increases gradually
but suddenly falls
Rectangular:
Impulses increases rapidly,
maintained there for
sometime & falls abruptly

1. Stimulation of Sensory Nerves
Mild prickling sensation is experienced
It is not very marked because of short
duration
Causes reflex vasodilatation of superficial
blood vessels leading to slight erythema
Vasodilatation is confined to superficial
tissues so is of little practical importance

It occurs if the current is of sufficient
intensity, causing contraction of muscles
which they supply
 The contraction is tetanic in type as stimulus is
repeated 50 times or more per sec
 If this type of contraction is maintained for
more than a short period of time, muscle
fatigue occurs. So, the current is commonly
surged to allow for muscle relaxation

When muscle contracts, changes taking
place within a muscle are increase in
metabolism, increase in demand for
oxygen and nutrients and increase output
of waste products
As muscle contracts & relax, exert a
pumping action on veins and lymphatic
vessels thus, increases the venous and
lymphatic return

 The current required to produce
a contraction of denervated
muscle with an impulse lasting
for 1 ms is usually too great to
be tolerable for treatment
purposes

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 rid of waste
products.

The ions move one way during one phase of
the current and in the reverse direction
during the other phase of the current if it is
alternating.
If the two phases are equal, the chemicals
formed during one phase are neutralized
during the next phase but if phases are not
similar there are chemical changes which
can cause electrolyte burn.
In faradic current, chemical formations are
not great enough to give rise to a serious
danger of burns because of the short
duration of impulses.

Increases joint mobility
Increases lymphatic activity
Helps in healing
Analgesic effect
Does not produce chemical burn until
high intensity is used
Causes vasodilatation, in turn increases
circulation

 Reduces edema
 Controls acute & chronic pain
 Reduces & inhibits muscle spasm
 Reduces joint contracture
 Minimize atrophy
 Facilitates tissue healing
 Facilitates muscle re-education
 Facilitates fracture healing
 Strengthen muscles

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

 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.

 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.

 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.

 In oedema and gravitational ulcers,
the venous and lymphatic return
should be encouraged by the
pumping action of the alternate
muscle contraction and relaxation.

 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.

After trauma, there is inhibition
of muscle contraction, leading to
muscle atrophy.

1.Skin lesions:
Any large or open wound is contraindicated
for direct application of faradic current as it
can cause discomfort and pain
2.Infections:
Any infection must not be treated with low
frequency current because of danger of
spreading or exacerbating the condition

3.Inflammation:
Any acute inflammation with an
underline danger of infection or with
thrombosis as a complication is
contraindicated.
4.Thrombosis:
Patients with DVT (Deep Vein Thrombosis)
or atherosclerosis must not be treated
with faradic current as it will exacerbate
the condition

5.Marked loss of sensation:
If there is loss of sensation in the
limb being treated, low frequency
current must not be given as it can
cause chemical burn
6.Tuberculosis or Cancer:
The condition can exacerbate by this
current

7. Cardiac Pacemaker:
It is not advisable to apply low
frequency current in the area of thorax,
abdomen, or shoulder as it may interfere
with functions of pacemaker
8.Skin Diseases:
If there is any skin diseases like eczema,
fungus growth or similar conditions, low
frequency current is contraindicated as
it can be spread to same person or to
other

9.Unreliable patient:
Patients who cannot cooperate or
understand the dangers of treatment.
Eg :-very old or infant patients
10. Superficial metal:
Metals in the pathway of the current
will concentrate it and may cause a
burn.

Equipments Required:
• Low frequency electronic stimulator
• 2 leads [1cathode & 1anode]
• 2 suitably sized carbon/metal electrode
• Aqueous gel, a sand bag
• Bandage, straps, micropore or adhesive tape
• 2 small basin of warm water
• Towels, soap
• Insulating cream [petroleum jelly, vaseline]

 Position the patient comfortably in a relaxed
position
 Support the muscle to be stimulated in pain-
free position with area to be treated
adequately exposed
 In case of supine lying knees should be flexed
by keeping the pillows or towels under the knee
 Examine the area to be treated; note any cuts,
skin lesions and inflammations. Check that
there is no contraindication to treatment like
sensation

 Equipment should be tested prior to treatment by
placing the electrodes over the palm & increasing
intensity to check whether equipment is working
properly.
 Explain the procedure properly to patient that there
will be pricking sensation on area to be treated &
there is no need to panic & if intensity will be high
he/she must tell.
 Clean the electrodes with soap water to avoid any
chemical on electrode & also clean the area to be
treated to remove any grease on skin which helps in
better penetration by reducing the skin impedence.

Place the active electrode on muscle &
inactive electrode on nerve trunk if for
group action. If it is for stimulating
individual muscle we will use pen
electrode.
Connect the electrodes properly to skin with
the help of tape/strap.
Explain the patient that during the
procedure he/ she should not move the limb
suddenly or do not touch the equipment

 Motor point stimulation
 Group muscle stimulation

 Stimulation which makes all the muscles
of a group work together
Satisfactory method of re-educating the
action of muscles which normally work
as a group, such as quadriceps, the small
muscles of the foot, and muscles of
pelvic floor

 This method has an advantage that each muscle
performs its own individual action & that the
optimum contraction of each can be obtained
 Selected when training a new muscle action or
when isolation of one muscle is indicated; e.g.
vastus medialis may be stimulated to overcome
a quadriceps lag, or abductor hallucis for
muscle weakness

Faradic current

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Faradic current