Lab guide

• Electromyography (EMG)


  Aka biofeedback
• Criteria for EMG


  • Good vision
  • Good motor control
  • Good comprehension and communication
  • No profound sensory deficit
• Infrared Radiation (IRR)


  Superficial heat
• IRR


  • Wien's Law
  • Lambert-Cosine Law
  • Inverse Square Law
• Types of IRR


  • Luminous IRR
  • Non-luminous IRR
• Luminous IRR


  Short, hot and glowing, tungsten and carbon components, deep structures
• Non-luminous IRR


  Long, pre-heat for 5mins, resistant wires, more superficial
• Distance for IRR


  • 18-24 inches away
  • 29-36 inches away
• Erythema Ab Igne


  Mottled appearance after exposure to radiation
• UVR and IRR source is sunlight, UVR is 40% and IRR is 60%
• Indications of UVR


  • Acne (face=E1, chest and back=E1-E2, back and shoulder=Up to E3)
  • Psoriasis (Leeds Regimen=E1 + __, PUVA=gold standard=_____ + UVA)
• Shortwave Diathermy (SWD)


  • Frequency: 13.56 MHz, 27.12 MHz, 40.68 MHz
  • Wavelength: 22m, 11m, 7m
• Methods and Techniques in SWD


  1. Electrostatic Field (Capacitor Technique: Coplanar, Contra-planar, Crossfire)

  2. Electromagnetic Field (Eddy Current=circular current produced by coils, Inductothermy: Coil Technique, Drum Technique)
• Microthermy (Microwave Diathermy)


  Produces sensation of heat and will increase tissue temperature
• Microthermy


  • Frequency: 2450MHz, 915-4339MHz
  • Wavelength: 122.5m, 330m
• Indications of Diathermy


  • Thermal (chronic musculoskeletal condition)
  • Non-thermal (acute infective disease)
• Contraindications of Diathermy


  • Metal implants
  • Acute injury
  • Pregnant uterus
  • Edema
  • Hemorrhage
• LASER


  Light Amplification by Stimulated Emission of Radiation
• Agents used in LASER


  • HeNe (emits visible light, superficial)
  • GaAs (emits IRR+invisible light, deep)
  • GaAlAs (for CTS)
• Types of LASER


  • Type I (0.5 mW, safe for momentary viewing)
  • Type II (1 mW, laser pointer, can cause eye damage after prolonged exposure)
  • Type IIIa (5 mW, therapeutic, can cause eye damage after brief exposure)
  • Type IIIb (500 mW, therapeutic)
  • Type IV (>500 mW, surgical/industrial cutting)
• Current


  The movement of ions or electrons in a conductor in response to a voltage force. It is directly proportional to the magnitude of the driving force (i.e., the voltage).
• Unit of Current


  Ampere (amp or A), but most therapeutic applications of current use milliamperes (10–3; mA, thousandths of an ampere) or microamperes (10–6; uA, millionths of an ampere).
• Voltage


  The force of attraction or repulsion created by an electric field represents potential energy. The greater the force, the greater the potential energy.
• Unit of Voltage


  Volt (or millivolt).
• Resistance


  Opposition to the flow of current and comes in many forms in the body.
• Unit of Resistance


  Ohm, Ω (omega).
• Capacitance


  Ability to store energy by means of an electrostatic field.
• Unit of Capacitance


  Farads (F).
• Ohm's Law


  A mathematical expression of how voltage, current, and resistance relate, where voltage equals current multiplied by resistance.
• Polar Formula (aka Erb's Law/ Peuger's Law)


  CCC>ACC>AOC>COC

  CCC = Cathode Closing Circuit

  ACC = Anode Closing Circuit

  AOC = Anode Opening Circuit

  COC = Cathode Opening Circuit
• DuBois-Reymond's Law


  The variation in current density, rather than the absolute current density, cause the depolarization of nerves or muscle tissue.
• Accommodation


  The process by which a nerve gradually becomes less responsive to stimulation; a stimulus of sufficient amplitude and duration that usually produces a response no longer does so.
• Rheobase


  The minimum current amplitude with very long pulse duration, as required to produce an action potential. It is a measure of current amplitude. Normal Value = 2 to 28 milliamperes (mA).
• Chronaxie


  The minimum duration it takes to stimulate that tissue at twice rheobase intensity. It is a measure of time(duration). Normal Value = <1 millisecond (ms).
• Cathode vs Anode


  • pH Value
  • Physiologic Effects and Purpose
  • Risk for Burn
  • Effect on Skin Color
  • Nerve Conduction Velocity (NCV)
  • Polarity
  • Gas Bubble
  • Sample Medications for Iontophoresis
• Law of Repulsion in Iontophoresis


  According to the book of Bellew J. W., underlying the process of iontophoresis is the electrical repulsion of ions. Using ES to moved charged ions into the target tissues has long been the cornerstone explanation for iontophoresis. And, according to Swati Rawat, it is for movement of ions to improved systemic bioavailability. For example, when you apply the law of repulsion in iontophoresis due to muscle spasm, the drug will control and will deliver accurately where affected tissue locates so that to aim and treat what the target area.
• NMES Precautions/Contraindications


  • Precautions
  • Contraindications
• NMES Waveform


  Symmetrical or asymmetrical biphasic pulsed current, burst-modulated alternating current.
• NMES Electrode Placement


  Identify the motor point for optimal electrode placement over the peroneus longus. Both electrodes should be placed over muscular tissue, avoiding placement of the distal electrode over more tendinous area. Electrodes may be adhesive-disposable or carbon-gelled but should be proportionate to the size of the area to be stimulated. Too-large electrodes may result in cross-stimulation of additional muscles, and too-small electrodes will increase current density and likely result in an uncomfortable sensation.