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ELECTRICAL STIMULATION
PRESENTER:DR N. BROJENDRO SINGH
MODERATOR: PROF N.ROMI SINGH
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ELECTRICAL STIMULATION
Application of suitably modified electric current to stimulate excitable tissues like nerves and muscles to produce therapeutic benefits
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ELECTRIC CURRENT
• Flow of electric charge• Two types: direct current and
alternating current• Direct current (DC) : the
unidirectional flow of electric charge.• Alternating current(AC) : flow of
electric charge periodically in reverses direction
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• Electric current can stimulate excitable tissue in body.
• Intermittent current are used• Current duration range used:(0.01ms-3sec)• Short duration less than 10 ms is faradic
type-used for stimulation of normal muscle• Long duration more than10ms is called
interrupted galvanic type –used for stimulation of denervated muscles
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FARADIC CURRENT
• Interrupted direct current • Pulse duration- (0.1 – 1
ms ) • Frequency (50 – 100 Hz)• Surged form of current is
used
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FORMS OF FARADIC TYPE CURRENT
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PHYSIOLOGICAL EFFECT OF FADADIC CURRENT
• Sensory nerve stimulation• Motor nerve stimulation
stimulation with 50 Hz frequency and 0.1 – 1ms with surged current
• Effect on muscle contraction:• Effect on denervated muscles
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CHEMICAL EFFECTS
• Produces chemical changes in electrodes
• Current flow in one direction for short periods
• No serious danger of burns
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STIMULATION OF MOTOR POINTS
• Superficial location of motor nerve• Usually located at upper and middle
one-third of belly of muscles• Suitable frequency and duration is
used
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INDICATIONS OF FARADIC CURRENT
• Facilitation of muscle contraction
• Re – education of muscle action
• Training of new muscle action
• Neuropraxia of a motor nerve
• Severed motor nerve• Improved venous and
lymphatic drainage• Prevention and loosening of
adhesions
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INTERRUPTED DIRECT CURRENT
• Frequency of 30 Hz• Duration 100 ms• Applied through a
potentiometer
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TYPES OF INTERRUPTED DIRECT CURRENT
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PHYSIOLOGICAL EFFECTS OF INTERRUPTED DIRECT CURRENT
• Stimulation of denervated muscles
• Stimulation of sensory nerves
• Stimulation of motor nerves
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INDICATIONS
• To produce contractions of denervated muscles
• Re –education of muscles in early phase of re-innervation
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PHYSIOLOGICAL RESPONSE TO ELECTRICAL CURRENT
• As electricity moves through the body's conductive medium, changes in the physiologic functioning can occur at various levels
CellularTissueSegmentalSystematic28/11/2015 at 2.00pm
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EFFECTS AT CELLULAR LEVEL
• Excitation of nerve cells• Changes in cell membrane
permeability • Stimulation of fibroblast,
osteoblast• Modification of
microcirculation
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EFFECTS AT TISSUE LEVEL
• Skeletal muscle contraction
• Smooth muscle contraction
• Tissue regeneration28/11/2015 at 2.00pm
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EFFECTS AT SEGMENTAL LEVEL
• 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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SYSTEMIC EFFECTS
• Analgesic effects as endogenous 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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ELECTRICAL STIMULATOR
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ELECTRODES• Purpose–Completes the
circuit – Interface
between electron and ion flow
– resistance to current
• Materials–Metallic–Carbon rubber– Self-adhesive
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ELECTRODE PLACEMENT• Electrodes spaced far apart penetrate
more deeply with less current density• Larger the electrode the less density• A multitude of placement techniques
may be used to create desire able clinical and physiological effects
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STIMULATION POINT• Motor Points– Superficial
location of motor nerve
• Trigger Points– Localized,
hypersensitive muscle spasm
– Trigger referred pain
– Arise secondary to pathology
• Acupuncture Points– Areas of skin
having decreased electrical resistance
–May result in pain reduction
• Traumatized Areas– Decreased
electrical resistance28/11/2015 at 2.00pm
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TYPES
• Neuromuscular electrical stimulation(NMES)
• Functional electrical stimulation(FES)
• Transcutaneous electrical nerve stimulation(TENS)
• Interferential therapy unit28/11/2015 at 2.00pm
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NMESNMES applies electrical impulses to the
nervous system to stimulate sensory and/or motor neurons
Common Uses• Relaxation of muscle spasms• Prevention or retardation of disuse
atrophy• Improvement of local blood circulation• Re-education of the muscle
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FUNCTIONAL ELECTTRICAL STIMULATION
• Technique that used electric currents to activate nerves innervating extremities affected by paralysis and neurological disabilities to restore normal functions
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MECHANISM OF FES• Stimulate muscles in a programmed
synergystic sequence that allow patient to accomplish a specific functional movement pattern
• Multichannel microprocessors are pre-programmed to executevariety of specific movement
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USES
• Prevent or correct diffuse atrophy• Improve ROM in stiff joints and
spasticity• Re- education of new muscle
action in muscle and tendon transfers
• Supplementation or substitution of orthosis
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PARAMETER OF FES CURRENT
• Frequency-(12-100Hz)• Intensity of current-(90-200)mA• Pulse duration(20-300)msec
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STRENGHT- DURATION CURVE
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TENS• Electrical stimulation which primarily
aims to provide a degree of symptomatic pain relief by exciting sensory nerves
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MECHANISM OF TENS• Gate Control Theory(Malzack and Wall)• Activation of peripheral sensory Aβ fibers
stimulates the inhibitory interneuron in substansia gelatinosa in dorsal horns of the spinal cord
• Activated interneurons produces inhibition of pain carrying A-delta and C fibres and closes spinal pain gate to prevent painful impulse to reach at sensory cortex
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DESCENDING PAIN CONTROL
• stimulation of smaller peripheral Aδ and C fibers through the CNS causes a release of enkephalins blocking pain at the spinal cord
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ENDOGENOUS OPIATE PAIN CONTROL
• Noxious stimulus causes release of β–endorphins and dynorphin resulting in analgesia
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TYPES OF TENS
High TENS (Sensory Level)o Duration (100-500 µsec)o Frequency (100-150Hz)o Sensory-level outputo Activates spinal gate
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LOW TENS
• Duration (100 to 150 µsec)• Low pulse frequency (1 to 5 Hz)• Motor-level output• Modulation through release of β-
endorphin
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CLINICAL APPLICATIONS• Acute and chronic pain,• Back and cervical muscular
and disc syndromes,• Arthritis• Shoulder syndromes• Neuropathies• Many other painful conditions
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ELECTRODE PLACEMENT Negative electrode
• Spinal nerve roots• Painful sites •Dermatomes• Myotomes• Trigger points• Acupuncture points
Positive electrodes• Placed close to spinal
segment
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INTERFERENTIAL THERAPY• Two medium frequency currents
pass through the tissues simultaneously
• Their paths cross; and interfere with each other
• Gives an interference or beat frequency which has low-frequency stimulation
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MECHANISM OF INTERFERENTIAL THERAPY
• Low frequency stimulation of muscle and nerve tissues at sufficient depth without painful and side effects
• Medium frequency currents penetrate the tissues with little resistance, but the resulting interference current allows effective stimulation of the biological tissues
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ELECTRODE PLACEMENT
• When electrodes are arranged in a square and interferential currents are passed through a homogeneous medium - a pattern of interference will occur
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ELECTRODE PLACEMENT• Ensure adequate coverage of the
stimulated area • Placement of the electrodes should
be such that a crossover effect is achieved in the desired area
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CONTRAINDICATIONS• Undiagnosed pain• Pacemakers • Heart disease • Epilepsy • Pregnancy: first trimester-over the uterus• Over the carotid sinus • On broken skin • On dysaesthetic skin • Over the eyes, larynx, pharynx, over
mucosal membranes28/11/2015 at 2.00pm
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THANK YOU
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