Electrical Stimulation Principles & Physiology
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Questions and Answers

Which type of electrical stimulation is primarily used for pain management?

  • NMES
  • FES
  • Iontophoresis
  • TENS (correct)

    • Iontophoresis is used for stimulating muscle contractions.

    False

    What does NMES stand for?

    Neuromuscular Electrical Stimulation

    The type of electrical stimulation used for wound healing is _______.

    <p>high volt</p> Signup and view all the answers

    What is the primary function of FES?

    <p>Orthotic substitute</p> Signup and view all the answers

    C fibers are responsible for sensory perception.

    <p>False</p> Signup and view all the answers

    What is the all-or-none principle in relation to muscle fibers?

    <p>It states that a muscle fiber will either respond fully or not at all when stimulated.</p> Signup and view all the answers

    To achieve muscle contraction in a denervated muscle, _______ is required.

    <p>direct current</p> Signup and view all the answers

    Match the following types of electrical stimulation to their primary use:

    <p>TENS = Pain relief High volt = Wound healing Iontophoresis = Drug delivery NMES = Muscle re-education</p> Signup and view all the answers

    What factors can affect the speed of nerve conduction?

    <p>Prolonged icing, pressure, anoxia/ischemia can slow nerve conduction; myelination can increase speed.</p> Signup and view all the answers

    Which contraction occurs first when using electrical stimulation?

    <p>Large motor units first</p> Signup and view all the answers

    Voluntary contractions are more fatiguing than electrically generated contractions.

    <p>False</p> Signup and view all the answers

    What is the relationship between strength and duration in electrical stimulation?

    <p>Inverse relationship</p> Signup and view all the answers

    The only electrical stimulation unit capable of delivering enough charge to reach the threshold of the muscle membrane is _____ because it has a long duration.

    <p>DC</p> Signup and view all the answers

    Match the following responses to their descriptions:

    <p>Sensory response = Buzzing tingling sensation Motor response = Weak contraction that strengthens Pain response = Discomfort felt during stimulation</p> Signup and view all the answers

    What happens when the amplitude increases while duration remains constant during electrical stimulation?

    <p>Motor response becomes stronger</p> Signup and view all the answers

    The threshold for activating sensory nerves is higher than for pain nerves.

    <p>False</p> Signup and view all the answers

    Which type of motor unit recruitment pattern is seen during voluntary contractions?

    <p>Small motor units recruited before large</p> Signup and view all the answers

    Pulses with short durations require _____ amplitude to reach threshold.

    <p>higher</p> Signup and view all the answers

    What is the sequence of activation of nerves during electrical stimulation?

    <p>Sensory - Motor - Pain</p> Signup and view all the answers

    Study Notes

    Electrical Stimulation Principles

    • Clinical Applications:
      • Pain relief (TENS, IFC)
      • Edema reduction (high volt, NMES)
      • Muscle re-education/strengthening (NMES, Russian)
      • Range of motion (ROM) improvement (NMES)
      • Wound healing (high volt)
      • Denervated muscle activation (direct current)
      • Drug delivery (iontophoresis)
      • Muscle spasm/guarding (NMES)
      • Functional electrical stimulation (FES) for orthotics (e.g., drop foot, anterior tibialis) (NMES)

    Physiology of Electrical Stimulation

    • Action Potential Basics: Electrical stimulation works by creating action potentials in nerve and muscle fibers. The strength and duration of the stimulus must reach the tissue's threshold to initiate this response.

    • Stimulus Characteristics:

    • Strength: Intensity and amplitude influence the stimulus's ability to reach threshold.

    • Duration: Longer pulses generally need less intensity to reach threshold than shorter pulses.

    • Rise Time: The speed of the pulse's increase also affects its ability to excite tissue.

    • Charge: The area under the stimulus waveform. Critically important for depolarization.

    • Sensory vs. Motor Stimulation: Sensory, motor or pain stimulation of nerve stimulation depends on the type of nerve fibers activated (sensory, motor, or pain fibers).

    • Denervated Muscle Stimulation: Denervated muscles require higher stimulus intensity and longer duration (DC) due to a higher threshold compared to normally innervated muscles.

    • Conduction Speed: Factors like prolonged icing, pressure and ischemia all negatively impact nerve conduction speed. Myelin sheath promotes faster conduction through saltatory conduction.

    • Conductors and Insulators:

      • Conductors: Nerve, muscle, blood, motor points, trigger points have low electrical resistance.
      • Insulators: Skin, adipose tissue, hair, callus, scar tissue have high electrical resistance.

    Motor Units

    • Motor Unit: A motor neuron and the muscle fibers it innervates.
      • Small Motor Units: Fine motor control (e.g., eye muscles, 1:5 nerve-to-muscle fiber ratio).
      • Large Motor Units: Gross motor control, force production (e.g., quadriceps muscles, 1:50 ratio).

    Voluntary vs. Electrically Generated Contractions

    • Voluntary Contractions:

      • Gradual recruitment of motor units.
      • Asynchronous firing for recovery.
      • Less fatiguing.

    • Electrical Stimulation Contractions:

      • Abrupt recruitment of motor units.
      • Synchronous firing; Fatigue more quickly.
      • Amplitude directly relates to the muscle recruitment strength.

    Strength-Duration Curve Interpretation

    • Inverse Relationship: Shorter pulses need higher intensity, while longer pulses need lower intensity to reach the same threshold.
    • Nerve Stimulation Sequence: Sensory → Motor → Pain (sensory threshold is lowest).
    • Amplitude Increase (Constant Duration): Higher amplitude with constant duration will progressively create a stronger contraction as more motor units are recruited.

    Threshold Considerations

    • Muscle vs. Nerve Thresholds: Muscle membrane has a higher threshold for activation by electrical stimulation than nerve membranes, thus requiring differing stimulus parameters.

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    Description

    Explore the critical principles and physiological mechanisms of electrical stimulation in clinical applications. This quiz covers diverse topics, including pain relief, muscle re-education, and the intricacies of action potentials. Test your knowledge on various techniques and their effectiveness in therapeutic settings.

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