RHPT – 353
1435 – 1436 H– IST SEMESTER
ELECTROTHERAPY – 2
(LOW & MEDIUM FREQUENCY)
DR/ AMAL MOHAMED ABD EL BAKY & MR. CHANDRASEKAR.L
Lecture outline
This lecture deals about the basics of
electrotherapy in the following sub-categories;
 Terminology, Introduction, Classification of
electrotherapy & basic model of electrotherapy
intervention.
 Classification of frequencies.
 Key concepts in Electrotherapy / Electro physical
agents
 Basics of Electric current / Electricity.
 Shock, types & Prevention strategies
Learning Objective
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At the end of this lecture, the students will be able to;
Define electrotherapy, classification of electrotherapy,
Characteristics of a charged body, potential, difference of
potential, capacitance, EMF, Electric current, types of therapeutic
Current, Dangers of electricity & its prevention strategies.
Understand the concept of basic model of electrotherapy
intervention.
Recall most of the stimulating agents.
Compare the similarities & differences in L.F. currents.
Differentiate the flow of current to different biological tissues.
Introduction - Electrotherapy
Electro – Electric Current / Electrical •
Energy.
Modality – Machines/ Equipment's. •
Therapy – Treatment of disease, Non •
surgical treatment approach.
It means various forms of THERAPEUTIC •
applications using ELECTRICAL ENERGY
as primary source.
Electrotherapy - Definition:
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Electrotherapy can be defined as the
treatment of patients by electrical
means.
Classification of therapeutic currents according to frequency
• Current in which the
direction of electron
flow changes
periodically with a
frequency of 1-1000
Hz.
• Those current of
10,000 Hz or
more.
Low
Frequency
High
frequency
• Current in which
alternate the
direction of flow of
electrons with a
frequency between
1000-10.000 Hz .
Medium
Frequency
Instruments used in Electrotherapy
I-Low & Medium
Frequency Modalities
• TENS (transcutaneous
Electrical Nerve
Stimulation)
• High-Voltage pulsed
stimulation
• Neuromuscular
Electrical Stimulation
• Galvanic Stimulation
• Russian current
• Faradic current
• Iontophoresis
• Interferential Therapy
(I.F.T)
III-High Frequency
Modalities
Shortwave Diathermy
(S.W.D)
Microwave Diathermy
(M.W.D)
Ultra Sound Therapy
(U.S)
Shockwave therapy
IV-Actinotherapy
Infra - red Radiations
(I.R.R)
Ultraviolet Radiations
(U.V.R)
Laser Therapy
Other Modalities
Continuous Passive
Mobilizer (C.P.M)
Traction unit (Cervical &
Lumbar Traction)
Paraffin Wax Bath
(P.W.D)
Hydrocollator Unit
Hydrotherapy –
Whirlpool therapy
Fluido - Therapy
LOW & MEDIUM FREQUENCY MODALITIES
IFT
IONTOPHORESIS
TENS
FES
HVPS
Introduction – Changing nature of Electrotherapy
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Electrotherapy is a long-established place in
therapy practice.
From the published & experimental evidence, it
appears that electrotherapy can be clinically
effective.
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The evidence would suggest that when the appropriate
modality is applied at the right dose for the presenting
problem, it can make a significant contribution to the
improvement & well being of the patient.
For any therapeutic intervention to be effective there is a
need for a clear assessment, a rationalization of the
problems(s) & the construction of a proposed treatment
plan that matches the needs of the individual taking into
account their holistic circumstances, not just their presenting
signs & symptoms.
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The thinking therapist then re-evaluates the outcomes as the
treatment progresses, modifying the treatment package in
the light of these results. (+, -)
Treatment package tailoring is an essential skill for any
therapist.
The research evidence suggests that electrotherapy can be
effective as an element of treatment. Further work is
needed to evaluate the combinations or treatment
packages – that are most effective.
The classification of Electrotherapy (Electrophysical Agents – EPAs) Electrical Stimulation
Agents / Modalities
Thermal
Agents / Modalities
Non Thermal
Agents / Modalities
Infra Red Irradiation (IRR)
[Pulsed] Ultrasound
Interferential Therapy (IFT)
Shortwave Diathermy (SWD)
Low Intensity Pulsed Ultrasound (LIPUS)
Neuromuscular Electrical Stimulation (NMES)
Microwave Diathermy (MWD)
[Pulsed] Shortwave Therapy (PSWT)
Functional Electrical Stimulation (FES)
Other RF Therapies
[Pulsed] Laser Therapy
(LLLT / LILT)
Faradic Stimulation
Hydrocollator Packs
[Pulsed] Microwave Therapy
Iontophoresis
High Voltage Pulsed Galvanic Stimulation
(HVPGS)
Wax Therapy
Balneotherapy
( inc spa/whirlpool)
Low Intensity RF Applications
Pulsed Electromagnetic Fields (PEMF’s)
Fluidotherapy
Microcurrent Therapies
Therapeutic Ultrasound
Magnetic Therapies
Laser Therapy
Pulsed Magnetic Therapy
Transcutaneous Electrical Nerve Stimulation
(TENS)
Low Intensity Direct Current (LIDC) and Pulsed
LIDC
Twin Peak Monophasic Stimulation
Diadynamic Therapy
H Wave Therapy ; Action Potential System
(APS)
Russian Stimulation : Medium Frequency
Stimulation
Rebox Therapy; Scenar Therapy
Microcurrent Therapy (MCT)
Static Magnetic Therapy
Cryotherapy / Cold Therapy / Ice
/ Immersion Therapy
Microcurrent Therapy
Basic Model of Electrotherapy Intervention
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A simple, but effective clinical decision making model
(represented in the adjacent diagram) can be
utilized.
All electrotherapy modalities (with the exception of
biofeedback) involve the introduction of some
physical energy into a biologic system. This energy
brings about one or more physiological changes,
which are used for therapeutic benefit.
Basic Model of Electrotherapy Intervention
Classification of frequencies
Low frequency current
ranging from 0 to 1000 Hz
Medium frequency current
ranging from 1000 to 10000 Hz
High frequency current
ranging from 10000 Hz onwards
ELECTRICITY – Basic concepts explained
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Matter- any material that occupies space and has mass.
Elements - all matter are made of elements, over 100
elements are known.
Compounds - combination of two or more elements joined
together at the atomic level.
Atom - the smallest recognized particle of matter that
retains the properties of a given element. Atoms of
elements are combined together to form compounds.
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The atom consists of :
A) Protons - very dense, positively charged
B) Neutrons - dense, neutrally charged
C) Electrons - negatively charged particles that orbit very
rapidly about the nucleus of an atom.
Atomic charge balance - all atoms contain the same
number of negative electrons as positive protons, thus as
neutrons have no charge, then net positive charges = net
negative charges (protons = electrons)
Valence electrons - the electrons present in the outer
energy level that are available for atomic bonding.
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Ionic Bonds - bonding in which one or more valence
electrons are transferred from one atom to another.
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Ions - electrically charged atoms.
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positive ions - tend to lose electrons during bonding
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negative ions - tend to gain electrons during bonding.
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Two particles of opposite charge attract each other & two
particles of the same charge repel each other.
Potential
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It is electrical condition of that body when compared to
the neutral potential of the earth
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Bodies with an excess of electron are called negative
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Bodies deficient in electrons are called positive
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The Unit of potential is volt
Capacitance
It is the ability of the body to hold an electrical charge
Capacitance depends upon the material and surface area of
the body. There is inverse relationship between capacitance and
potential (larger the body the smaller the potential)
Difference of potential
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Exists between similar bodies charged with different quantities of
electricity. Electron moves from the more negative to less negative
one.
The force producing the movement is called an electro motive force
(EMF)
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The charged body is continually seeking to attain
its neutral state: if negative, by losing electrons; if
positive gaining electrons.
Characteristics of charged body
These shows certain properties
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1.The lines of force (LOF) surrounding an isolated charged
body are straight.
2.Lines of force (LOF) repel one another.
3.LOF pass more easily through conductors than through
insulators
4.LOF concentrate on that part of the surface of a charged
body nearest to another object over which they can exert an
influence.
Electric Fields - LOF

An electric field exists around any charged particle. If a
smaller charge that is free to move is placed in the field,
the paths it will move along are called lines of force.
Examples of electric fields near charge particles and plates
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Electromotive force - EMF
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Electromotive force, or most commonly emf (seldom
capitalized), or (occasionally) electromotance is "that
which tends to cause current (actual electrons and ions) to
flow.
More formally, emf is the external work expended per unit
of charge to produce an electric potential difference
across two open-circuited terminals.
The electric potential difference is created by separating
positive and negative charges, thereby generating an
electric field.
The created electrical potential difference drives current
flow if a circuit is attached to the source of emf.
Electrical energy
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Electrical energy is the energy carried by moving
electrons in an electric conductor.
It cannot be seen, but it is one of our most useful
forms of energy because it is relatively easy to
transmit and use.
Electric Current / Electricity

An electric current is the flow of electric charge (Usually
electrons) in a circuit.
Factors essential for production of electrical current are
1. Potential difference (PD)
2. Conducting pathway (between two points of PD)
Higher
potential
It is measured in – Amperes (A)
PD (+ -)
Lower
potential
Presence of Potential difference
Generation of electric current / electricity
Types of electricity / Current
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Currents can be classified into
1 . Alternating (AC)
2 . Direct (DC)
3 . Pulsatile (PC)
TYPES EXPLAINED
1. Direct current (DC)
The current flows only in one direction.
2. Alternating (AC)
The continuous flow of
electrons is bidirectional
Electrons flowing in an
alternating current always
move from the negative
to positive pole
3.Pulsatile (PC)
Contains three or more pulses grouped
together and may be undirectional or bidirectional
CURRENT FLOW THROUGH BIOLOGIC TISSUES
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Electrical current tends to choose the path that offers the
least (LESS) resistance to flow.
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The conductivity of the different types of tissue in the body
is variable. Typically, tissue that is highest in water content
(highest in ion content) is the best conductor of electricity.
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The skin has different layers that vary in water content, but
generally the skin offers the primary resistance to current
flow and is considered an insulator.
CURRENT FLOW THROUGH BIOLOGIC TISSUES
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Blood is a biologic tissue that is composed largely of water and ions and is
consequently the BEST electrical conductor of all tissues.
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Muscle is composed of about 75 percent water. Muscle tends to propagate an
electrical impulse much more effectively. So it is a good conductor.
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Peripheral nerve conductivity is approximately six times that of muscle.
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Fat contains only about 14 percent water and is thought to be a poor conductor.
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Bone is extremely dense, contains only about 5 percent water, and is considered to
be the poorest biologic conductor of electrical current.
Therapeutic uses of electricity –
Focusing on Low frequency currents
Main uses of electricity are:
1. Muscle contraction
Re education of the muscle
To improve muscle strength
To prevent atrophy of muscles
To increase range of motion
To increase muscle pump contraction
Cont….
2.Sensory stimulation
To reduce pain
Used as placebo effect
3.Ion movement
4.Analgesia
5.Recent researches shows
Fracture healing
Wound healing
Ligament and tendon healing
Terminology – APTA monograph (2001)
Sl.no
Recommended term / Electrical
Terminology
Outdated, Vague & Erroneous
Terminology
1.
Direct current
Galvanic current
2.
Faradic current
3.
Pulsed biphasic asymmetric
balanced current
High-voltage pulsed current
4.
Balanced Waveform
Zero net DC
5.
Pulse duration
Pulse width; pulse length
6.
Current amplitude
Current intensity
7.
Frequency
Rate
8.
Waveform
Impulse
9.
On:Off ratio
Mark:space ratio
10.
Ramp
Surge
High-voltage pulsed galvanic current
Dangers of electricity
• Definition
shock
• A shock is a painful stimulation of
sensory nerves caused by sudden flow,
cessation or variation in the current
passing through the body.
Severity
of shock
• The greater the current which
passes through the body,
more severe is the shock.
Most apparatus used in physiotherapy departments is
plugged into the mains supply of 240/110 volts and
frequency of 50/60 Hz. This therefore represents a
Danger of electric Shock.
Dangers of electricity – Cont….
Severity of shock
Severity of shock
• If exposed
parts of the
circuit are
touched with
damp ( wet)
hands the
shock is
more likely
to be severe
than if the
hands are
dry.
• The severity of
the shock also
depends on the
path taken by the
current.
• The strong current
through the head,
neck, heart or
whole body
prove fatal.
Severity of shock
• Shocks are also generally
more severe with
alternating current than
with direct current
• because the intensity of
alternating current (AC) is
continually changing and so
it provides stronger
sensory stimulation.
• it may also produce tetanic
muscle contractions, which
make it impossible for the
victim to let go off the
conductor.
A sudden increase in the current.
If the patient
touches the
exposed part of
the circuit
On making
contact with metal
casing of
apparatus
can also occur if
the intensity
control is turned
up Suddenly)
Types & effects of Shock
Minor shock
• frightened
• Distressed
• usually does
not lose
consciousness
.
Severe shock
• Fall in blood
pressure (BP)
• Sometimes
loss of
consciousness
.
Extreme shock
• Cessation of
respiration (This
is recognized by
absence of respiratory
movements and
cyanosis.)
• Cardiac arrest
• this is recognized by
absence or
abnormality of
respiratory
movements ,
absence of pulse in
the carotid artery
and fully dilated
pupils.
Treatment of electric shock
The first step is to
disconnect the victim from
the source of supply; the
current should be switched
off at once.
If there is no switch in the
circuit the victim must be
detached from the contact
of conductor.
Following a minor shock the
patient is reassured and
allowed to rest.
Water may be given to
drink.
Must avoid hot drinks
because that in turn can
cause vasodilatation and
sweat
Burn
It caused by:
 Contact of the metal to the skin
 Over dosage
 Skin lesion
 Metal in the part.
Concentration of current
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It is caused by:
The presence of un-dissolved salt in solution
Creases on the pad
Pads unevenly moist
Any raised skin edges
Precautions
Check the equipment
thoroughly.
Wires should be
checked for insulation
Proper instructions should
be given to the patient