Presentation 21 4-11electrotherapy
Upcoming SlideShare
Loading in...5
×

Like this? Share it with your network

Share
  • Full Name Full Name Comment goes here.
    Are you sure you want to
    Your message goes here
    Be the first to comment
No Downloads

Views

Total Views
2,338
On Slideshare
2,338
From Embeds
0
Number of Embeds
0

Actions

Shares
Downloads
78
Comments
0
Likes
2

Embeds 0

No embeds

Report content

Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

Cancel
    No notes for slide

Transcript

  • 1. Practical issues of EPAs restricted to low frequency currents Thangamani Ramalingam
  • 2.
    • Section 1- BASICS
    • Section 2- CLINICAL DECISION MAKING
    • Section 3- THE PRACTICAL ISSUES
  • 3. Electrical Stimulation The In’s & Out’s of Getting Zapped
  • 4. Electrical Currents
    • Continuous Currents:
      • Direct Current (DC) – polarity remains constant
        • Iontophoresis
        • Car battery
      • Alternating Current (AC) – polarity at each end is constantly reversed
        • Household current
    • Pulsatile Currents:
      • Monophasic – similar to DC (either +/-) but is not constant
      • Biphasic – similar to AC (+/- phases) but due to interpulse intervals it can’t be AC
      • Polyphasic
  • 5. Direct Current
    • DC
    • Uninterrupted unidirectional
    • flow of electrons
    • Pattern – square wave
    • recognized by continuous
    • current flow only on one side of
    • the baselines
    • Electrons travel from the
    • cathode to the anode
    • “ Galvanic” can be used to describe DC
    • Example: Flashlight
      • Positive pole lacks electrons, Negative pole has excess electrons
      • Electrons leave the (-) pole, go through the wire, then the bulb & back to the (+) pole. (When electrons = at (-) & (+) poles the battery is dead!)
  • 6. Alternating Current
    • AC
    • Bidirectional flow of
    • electrons – direction &
    • magnitude of flow reverses
    • although magnitude may not
    • be = on both sides of the baseline.
    • AC possesses no true positive or negative pole.
    • Electrons shuffle back & forth between the 2 electrodes as they take turn being (+) & (-).
    • Household electricity uses AC.
  • 7. Pulsed Currents
  • 8. Pulse Attributes
    • A = Amplitude
    • B = Phase Duration
    • C = Pulse Duration
    • D = Interpulse Interval
    A B C D E F
    • E = Intrapulse Interval
    • F = Pulse Period
    B F
  • 9. Pulse Attributes
    • Pulse charge: # of electrons contained within a pulse
      • Expressed in micro coulombs
    • Pulse frequency: # of events per second
      • Measured pulses per second (pps) or the cycle frequency of AC is cycles per second (cps) or Hz
      • Low-frequency currents: less than 1,000 cycles or pulses per second (electrical stimulation units used for biological effects)
      • Medium-frequency currents: 1,000-100,000 pps/cps
      • High-frequency currents: greater than 100,000 pps/cps (used for heating effects- diathermy)
  • 10. Pulse Attributes
    • Pulse Rise Time: amount of time needed for the pulse to reach its peak value ( nanoseconds )
      • Rapidly rising pulses cause nerve depolarization
    • Pulse Decay Time: amount of time required for the pulse to go from its peak back to zero
    • Pulse Train: individual patterns of waveforms, durations &/or frequencies that are linked together (repeat @ regular intervals)
      • Amplitude Ramp: gradual rise &/or fall in amplitude of a pulse train (causes a gradual  in the force of m. contractions by progressive recruitment of motor units)
  • 11. Measures of Electrical Current Flow
    • Resistance: ( R ) – opposition to electron flow in a conducting material
      • Type, length, & cross-sectional area of the material & temperature of the circuit determine the amount of resistance offered to the flow of electrons
      • Conductors: materials allowing current to pass with relative ease
      • Resistors/Insulators: materials that tend to oppose current flow
    • Impedance: ( Z ) Alternating Current
      • Inductance: degree that a varying current can induce voltage (H – henry) (negligible in biological systems)
      • Capacitance: frequency-dependent ability to store a charge (C); many cell membranes are capacitors
  • 12. Circuit Types
  • 13. So What?
  • 14. What happens in the Body?
    • Current enters the body through a SERIES circuit.
    • Once the current enters the tissues, it takes many different PARALLEL paths.
    • Electrical stim is applied trans- cutaneously except for some bone growth stimulators that may be implanted into the muscle or bone.
    • Resting potential – potential difference between the inside & outside of the membrane
    • Cathode – depolarization of the nerve occurs
    • Anode – hyperpolarization of the nerve occurs
  • 15. What happens in the Body?
    • Cathode – pH becomes basic (greater than 7)
    • Anode – pH becomes acidic (less than 7)
    • Na + move towards cathode, picks up an electron, & through reaction with H 2 O, liquefies proteins, causing a general softening of the tissues in the area & a decrease in nerve irritability
    • Tissues under anode harden because chemical mediators for a coagulation of protein
    • Effects not as pronounced when monophasic, biphasic or AC are used
    • Na+ moves from inside the cell to the outside the cell allowing K+ to move into the cell (Sodium-potassium pump)
  • 16. Physiological effects of electrical stimulation
    • Cellular level
    • Tissue level
    • Segmental level
    • Systemic level
  • 17. Therapeutic Uses for Electrical Stimulation
    • Control acute & chronic pain
    • Reduce edema
    • Reduce & or inhibit muscle spasm
    • Reduce joint contractures
    • Minimize atrophy
    • Facilitate tissue healing
    • Facilitate muscle reeducation
    • Facilitate fracture healing
    • Strengthen muscle
  • 18. Clinical application of Electricity: minimizing the resistance
    • Reduce the skin-electrode resistance
      • Minimize air-electrode interface
      • Keep electrode clean of oils, etc.
      • Clean the skill on oils, etc.
    • Use the shortest pathway for energy flow
    • Use the largest electrode that will selectively stimulate the target tissues
    • If resistance increases, more voltage will be needed to get the same current flow
  • 19. Clinical Application of Electricity: Material of Circuit
    • Not all of the body’s tissues conduct electrical current the same
    • Excitable Tissues
      • Nerves
      • Muscle fibers
      • blood cells
      • cell membranes
    • Non-excitable tissues
      • Bone
      • Cartilage
      • Tendons
      • Ligaments
    • Current prefers to travel along excitable tissues
  • 20. Stimulation Parameter :
    • Amplitude: the intensity of the current, the magnitude of the charge. The amplitude is associated with the depth of penetration.
      • The deeper the penetration the more muscle fiber recruitment possible
      • remember the all or none response and the Arndt-Schultz Principle
  • 21. Simulation Parameter
    • Pulse duration: the length of time the electrical flow is “on” also known as the pulse width. It is the time of 1 cycle to take place (will be both phases in a biphasic current)
      • phase duration important factor in determining which tissue stimulated: if too short there will be no action potential
  • 22. Stimulation Parameter:
    • Pulse rise time: the time to peak intensity of the pulse (ramp)
      • rapid rising pulses cause nerve depolarization
      • Slow rise: the nerve accommodates to stimulus and a action potential is not elicited
        • Good for muscle re-education with assisted contraction - ramping (shock of current is reduced)
  • 23. Stimulation Parameters
    • Pulse Frequency: (PPS=Hertz) How many pulses occur in a unit of time
      • Do not assume the lower the frequency the longer the pulse duration
      • Low Frequency: 1K Hz and below (MENS .1-1K Hz), muscle stim units)
      • Medium frequency: 1K to 100K Hz (Interferential, Russian stim ,LVGS)
      • High Frequency: above 100K Hz (diathermies)
  • 24. Stimulation Parameter :
    • Current types: alternating or Direct Current (AC or DC)
      • AC indicates that the energy travels in a positive and negative direction. The wave form which occurs will be replicated on both sides of the iso -electric line
      • DC indicated that the energy travels only in the positive or on in the negative direction
    DC AC
  • 25. Stimulation Parameter:
    • Waveforms; the path of the energy. May be smooth (sine) spiked, square,, continuous etc.
    • Method to direct current
      • Peaked - sharper
      • Sign - smoother
  • 26. Stimulation Parameter:
    • Duty cycles: on-off time. May also be called inter-pulse interval which is the time between pulses. The more rest of “off” time, the less muscle fatigue will occur
      • 1:1 Raito fatigues muscle rapidly
      • 1:5 ratio less fatigue
      • 1:7 no fatigue (passive muscle exercise)
  • 27. Stimulation Parameter:
      • Average current (also called Root Mean Square)
        • the “average” intensity
        • Factors effective the average current:
          • pulse amplitude
          • pulse duration
          • waveform (DC has more net charge over time thus causing a thermal effect. AC has a zero net charge (ZNC). The DC may have long term adverse physiological effects)
  • 28. Stimulation Parameter:
    • Current Density
      • The amount of charge per unit area. This is usually relative to the size of the electrode. Density will be greater with a small electrode, but also the small electrode offers more resistance.
  • 29. Capacitance:
    • The ability of tissue (or other material) to store electricity. For a given current intensity and pulse duration
      • The higher the capacitance the longer before a response. Body tissues have different capacitance. From least to most:
        • Nerve (will fire first, if healthy)
        • Muscle fiber
        • Muscle tissue
  • 30. Capacitance:
    • Increase intensity (with decrease pulse duration) is needed to stimulate tissues with a higher capacitance.
    • Muscle membrane has 10x the capacitance of nerve
  • 31. Factors effecting the clinical application of electricity
      • Factors effecting the clinical application of electricity Rise Time: the time to peak intensity
        • The onset of stimulation must be rapid enough that tissue accommodation is prevented
        • The lower the capacitance the less the charge can be stored
        • If a stimulus is applied too slowly, it is dispersed
  • 32. SECTION-2
  • 33. HISTORY OF ES
    • 420B.C-hippocrates-in torpaedo fish
    • 46A.D-scribonius largus-gout/headache
    • 1700-luigi galvani & alessantro volta
    • 1745-leyden jar for ES
    • 1831-michael faraday
    • 1850s-duchene-motor points(father of ES)
    • 1909-rheo/chron-louis
    • 1916-SD curve-Adrian
    • FES-1961-liberson
    • 1962-HVPC-robert becker
  • 34. Recent perceptions in practice
    • Clinical decision making
    • Research based
    • Client centered (patient preferences)
    • Context relevant (professional knowledge)
  • 35. No recipes only insight
  • 36.  
  • 37.  
  • 38. Basic Model of Electrotherapy
  • 39. Electrotherapeutic Windows
    •   Amplitude window
    • Frequency window
    • Acute window
    • chronic window
    • Energy based window
    • Time based window
    • Interval based window
  • 40. The Arndt-Schulz  rule or law
  • 41. FAM
    • Frequency Analysis Method
    • The external currents with different frequencies are considered to cause different effects in tissues. Thus we assume that tissue reactions on different frequencies in different states of the body will also differ from each other.
    • Measuring the sensory, motor and pain thresholds by stimulating the tissue with the interference current may offer a diagnostic tool in physiotherapy and rehabilitation
  • 42. S-D Curve
  • 43. Evidence based practice
    • Lack of Evidence
    • Vs
    • Evidence of lack
  • 44.
    •   Van Tulder  et al . [ 1 ] specify that "strong evidence" is provided by multiple high quality randomised trials with consistent findings,
    • "moderate evidence" is provided by consistent findings in multiple low quality trials, and
    • "limited or conflicting evidence" is provided by only one randomised trial or by inconsistent findings
    • “ No evidence”one low quality RCT/CCT
  • 45.  
  • 46. Recommendations
    • Effects of therapy
    • Experiences
    • Prognosis
    • Diagnostic tests
    • PEDro
    • Cochrane library
    • CINAHL
    • Pubmed
    • Pubmed
    • pubmed
  • 47. Critically appraised paper (peer reviewed) is more reliable
  • 48. Clinical guidelines always superior than systematic reviews
  • 49. Clinical guidelines as a resource for EBP
    • www.show.scot.nhs.uk/sign/
    • www.nice.org.uk
    • www.nhmrc.gov.au/publications
    • www.nzgg.org.nz
    • www.guideline.gov.usa
    • www.g-i-n.net/index.cfm(guidelines international network)
  • 50. SECTION-3
  • 51. The practical issues
    • Electricity is an element of PT modalities most frightening and least understood.
    • Understanding the basis principles will later aid you in establishing treatment protocols.
  • 52. TENS
    • Cathode is placed proximally in TENS except in AL-TENS
    • Transcutaneous Electrical Nerve Stimulation ( TENS ) uses similar-sized electrodes
    • Over superficial vascular structures because transmission of currents may go through neural tissue as well as ionic fluids
    • Can cause muscle contractions, but that is not why it is used
    • Moderate caffeine levels (200 mg, approx 2-3 c. coffee) may decrease effectiveness of TENS
  • 53. IFT
    • 4KHZ-pain relief
    • 2KHZ-muscle stimulation
    • Pre modulated/4EL
    • Able to penetrate tissues with little resistance
    • No accomadation/gildemeister effect
  • 54. Wound Healing: E- stim for Tissue Repair (ESTR)
    • Robert Becker – 1962
    • Theory - “Current of Injury”
      • normal bioelectric system, nonexcitable tissues have a charge
        • skin -----
        • deeper tissues +++++
        • neuraxis ++++++
        • periphery -------
      • Wounds - system is disturbed & creates a “current of injury” that initiates tissue healing . . . inflammatory process, migration of cells, etc..
      • Use of E-stim magnifies the “current of injury” to initiate, maintain, or speed the process.
  • 55. “ Current of Injury” cont...
    • Further research established
      • Wound tissue is (+) & skin around is (-); this difference is the “skin battery” or “current of injury” and must exist for proper healing; if it fails or is disrupted, then slow/no healing can occur. E -stim can help restore the “skin battery”.
    • Further supported by evidence that many chronic wounds lost (+) polarity; e-stim w/ the anode (+) over the wound enhanced healing. (using DC)
    • If healing plateaued, switching polarity = good outcome
      • Kloth & Feedar, Phys Ther , April 88
  • 56. Contemporary Theory: Galvanotaxis
          • Process can be corrected and/or enhanced by attraction of cells to the wound thru use of anode (+) or cathode (-)
            • Leukocytes, fibroblasts, endothelial & epithelial cells, etc.. all have polarity and can be electrically attracted.
            • Treatment polarity depends on stage of the wound
            • READ THE ARTICLE: Kloth & McCulloch (1996)
  • 57. Electrode Placement
    • Options
      • Directly over the wound
      • Directly in the wound *
      • Straddle the wound
    • More information FYI:
      • http:// medicaledu.com/estim.htm
  • 58. ELECTROTHERAPY TREATMENT OF SWELLING I EDEMA 20 min daily MOTOR Varies: need ms. pump N/A HVPC BIPHASIC RUSSIAN Reduction SUBACUTE I CHRONIC 30 Min/ 4 HRS during acute stage SUBMOTOR 120 PPS (--) HVPC Control of Formation ACUTE TIME RESPONSE FREQ Polarity CURRENT Rx STAGE
  • 59. Voluntary contraction Vs Electrical stimulation
    • Recruitment order
    • small->large
    • Fibre type
    • slow->fast twitch
    • Central fatigue
    • Fatigue resistant motor units first
    • More force-more fatigue
    • Opp
    • Opp
    • Peripheral fatigue
    • Opp
    • high/low-no difference
  • 60. Faradic Vs galvanic
    • AC/DC
    • Short duration pulse
    • <1sec or micro sec
    • DC
    • Long duration pulse
    • >1sec
    • elicits a muscle contraction from de -nervated muscle, but the phase duration is so long that C fibers are also stimulated
  • 61. Denervated muscle stimulation
    • ES may disrupt regenerating NMJ
    • Trauma of the muscle
    • Time consuming
    • Three stimulation sessions/day
    • three to five sets of 5-20 isometric contractions
    • 5s –rest period/contraction
    • 1m-rest period /set
    • pW >than chronoxie
  • 62. Muscle Contractions
    • 1 pps = twitch
      • 10 pps = summation
      • 25-30 pps = tetanus (most fibers will reach tetany by 50 pps)
      • 50-100 micro sec –sensory stimulation
      • 200-300 micro sec –motor stimulation
  • 63. Frequency selection:
    • 100Hz - pain relief
    • 50-60 Hz = muscle contraction
    • 1-50 Hz = increased circulation
    • The higher the frequency (Hz) the more quickly the muscle will fatigue
    • 1-4 Hz-beta endorphin
    • 40-100Hz-enkepalin,serotonin
  • 64. Electrocution and dangers
    • Electric and earth shock
    • ELCB
    • BF/CF areas
    • Guidelines by Robertson et al(2001)
    • AC is more dangerous than DC(P=V*I)
      • The strongest stimulation is where the current exits the body
  • 65. Unexpected effects of ES
    • Over and above the normal physiological and psychological limits
    • Skin
    • Eyes
    • General symptoms
    • Cardio-resp
    • Neurological
    • Attitude
    • musculoskeletal
  • 66. Risk Management
    • Risk grading-0,(1,2),3
    • Safety& maintenance( quality assurance)
    • Infection
    • Aversion
    • Children (guidelines)
  • 67. ES for neurological conditions
    • UMN lesion- FES
    • LMN lesion- enhance re innervations
    • maintain muscle property
    • UMN&LMN- no use (Eg: ALS)
  • 68. The history of FES before 19th century 
  • 69. First registered FES work Liberson, et al 1961
  • 70. Parastep (Sigmedics Inc.)
  • 71. Parastep System Components
  • 72.  
  • 73.  
  • 74.  
  • 75.
    • Restoration of hand function in C5-6 tetraplegia and CVA
      • Wrist movement must be preserved
      • 3 channels self-adhesive electrodes over motor points
      • Conductive panels in the glove make contact electrodes
      • Control: wrist movements (tenodesis) sensed by a transducer
        • Wrist flexed > extensors tension > hand opens
        • Wrist extended > flexors tension > hand closes
      • Independent Don-Doff
    Bionic Glove
  • 76. Lower Limb: Odstock foot drop stimulator
    • One channel stimulator
    • Stimulation:
      • common peroneal nerve at head of fibula (TA) or
      • popliteal fossa (withdrawal reflex)
    • Heel switch trigger:
      • Heel off > stimulation ON
      • Heel on > stimulation OFF
    • Rise and fall stimulation envelope can be adjusted
    • Odstock 2 Channel Stimulator (O2CHS) for bilateral dropped foot
  • 77. Handmaster (NESS, Israel)
  • 78. References
    • Electrotherapy in rehab-meryl roth gersh
    • Orthopaedic PT secrets-placzek & boyce
    • Electrotherapy explained-low and reed
    • Practical EBP- herbert
    • electrotherapyEBP-Tim watson
  • 79. QUERIES