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| Typical Number in Hospital: 3 | Cost Bands: 4 | References: 10 |
Electrotherapy and faradic treatment of muscle pain, strains, and oedema are sometimes ineffective at treating sites deep within the body because the electrical current required is restricted by the high impedance at the skin electrodes. Electrical impedance at the skin reduces rapidly as the frequency is increased but so does the therapeutic effect. A differential treatment system employs two medium frequency (e.g. 4000 Hz and 4010 Hz) stimulating currents fed through skin electrodes at the opposite corners of a square so that they interfere where they cross over at the centre of the square. A stimulating current at the beat frequency (the numerical difference between the stimulating frequencies) is produced in the treatment region.
A low beat frequency of, say, 10 Hz may be generated for the the treatment of muscle disorders, and a higher frequency (e.g. 100 Hz) generated for the relief of pain.
Such apparatus is used in the physiotherapy department, often in conjunction with suction electrodes which may also provide a therapeutic 'suction massage'.
Content and Design Copyright 2000 Dr. Malcolm C Brown. See Title Page for more details