Interferential Current for Pain Control

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Interferential Current for Pain Control

• Nan-Ying Yu
• ISUPT
• 2008/4/29

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INTRODUCTION

• IFC has been reported to have the advantage of
  reducing the skin resistance, and thus the
  discomfort normally incurred by traditional
  low-frequency currents, whilst still producing
  low-frequency effects within the tissues.

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PHYSICAL PRINCIPLES OF INTERFERENTIAL CURRENT

• IFC is produced by mixing two medium-frequency
  currents that are slightly out of phase, either
  by applying them so that they interfere within
  tissues, or alternatively by mixing them within
  the stimulator prior to application.

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PHYSICAL PRINCIPLES OF INTERFERENTIAL CURRENT

• One current is normally of fixed frequency, for
  example at 4000 Hz, and the other current is
  adjustable, for example between 4000 and 4200 Hz.
• Two currents summate or cancel each other out in
  a predictable manner, producing the resultant
  amplitude-modulated interferential current.

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PHYSICAL PRINCIPLES OF INTERFERENTIAL CURRENT

• The frequency of the resultant current will be
  equal to the mean of the two original currents,
  and will vary in amplitude at a frequency equal
  to the difference between these two currents.
• This later frequency is known as the
  amplitude-modulated frequency (AMF) or beat
  frequency.

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PHYSICAL PRINCIPLES OF INTERFERENTIAL CURRENT
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TREATMENT PARAMETERS Amplitude-modulated
frequency
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TREATMENT PARAMETERS Amplitude-modulated
frequency

• Low AMFs, elicit a beating or tapping
  sensation, whilst higher AMFs elicit a buzzing
  or tingling sensation.
• AMF settings between 1 and 130 Hz have been
  recommended for the treatment of pain.

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TREATMENT PARAMETERS Frequency sweep

• A frequency sweep has been claimed
• to reduce adaptation
• to allow stimulation of a greater range of
  excitable tissues

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TREATMENT PARAMETERS Quadripolar/bipolar
application

• Quadripolar application ? Clover-leaf pattern
  (frequency difference)
• Bipolar application ? modulation is always 100
  (full field) a easier alternative

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Quadripolar application
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TREATMENT PARAMETERS Suction versus plate
electrodes

• Flat carbon rubber electrode may be easier to
  apply to peripheral limbs
• Anatomic areas that are less accessible the
  suction option may be advantageous

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TREATMENT PARAMETERS

• Current Intensity
• Strong but comfortable stimulation
• Intensity should be slowly tuned up
• Treatment duration
• 10-20 minutes

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THEORETICAL PAIN RELIFE MECHANISMS WITH IFC

• The pain gate theory
• Increased circulation
• Descending pain suppression
• Physiological block of nerve conduction
• Placebo

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Evidence for theoretical analgesic mechanisms
with IC
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Adverse effects

• Burns
• Increased pain
• General malaise
• Nausea
• Vomiting
• Dizziness/faintness
• Migraine/headache
• Neurological effects

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Adverse effects

• Patients where disturbance of a thrombus, spread
  of infection or cancerous cell, or haemorrhage
  might result
• Pacemakers
• The abdomen during pregnancy
• The chest wall in patients with cardiac problems.