We have already covered why specificity is critical when using neuromagnetics. But, what are the variables in the application of magnetic therapy and why is it so easy to get it wrong?
- Duration of Exposure. Anecdotal reports show that an MRI can be quite therapeutic, but exposure to the field is usually no more than 20 minutes duration. For best results, most Q magnet applications need to be worn 24/7 for the duration of an acute injury and may need to be worn for months or years for more persistent pain condition.
- Timing of Treatment. New research is showing that to be effective in reducing inflammation after trauma, magnets may need to be attached as soon as possible after the injury.
- Strength of Field. The strength of a magnet has a lot to do with the depth of penetration and the effect it’s going to have on moving charged particles such as sodium and calcium ions moving through a cell membrane. There are three main varieties of therapeutic magnets; flexible rubber, ceramic and rare earths. See magnetic therapy for more details.
- Size of Magnet. A magnet’s size also affects the depth of penetration. The earth’s magnetic field is relatively weak at around 1 Gauss or 0.1 mTesla. However its magnetic field can be detected in planes travelling many miles above the earth. Q magnets have a variety of sizes to match the field to the location of the target tissue.
- Depth of Penetration. Magnetic fields dissipate quickly away from a magnet. If a therapeutic dose of the magnetic field does not reach the target tissue, e.g. around 4cm to the spinal cord in the lower back, then it is unreasonable to expect a therapeutic effect. See the Collacott study to beautifully illustrate this point.
- Location. Most of the flux lines emitting from a magnet will penetrate directly beneath its mass. Once again, if the magnet is not placed over the area so that the field envelopes the target tissue, then they are unlikely to work.
- Magnetic Field Gradients. Much of the promising research into magnetic therapy has involved magnetic field gradient generating devices. Magnetic field gradients are generated by the close interaction of multiple poles and exist where the magnetic flux lines bend sharply in space. University research by neurologists has shown that the four alternating poles of a quadrapolar or Q magnet have the greatest physiological effect on blocking pain signals.
Pulsed Magnetic Fields (PEMF) can vary with time and are said are to be pulsed or have a cycle or frequency. These are generated by running alternating currents through wire coils which generate the magnetic fields. Static magnets such as Q magnets are just that, static and have no frequency since the field does not vary with time. So this is one variation that cannot be modified with static magnets. The magnetic fields from Q magnets do vary spatially (in space) which is the subject of field gradients as discussed above.
As quoted in Colbert et al, (2008) “A recent systematic review of Static Magnetic Field trials for pain reduction concluded that the evidence does not support the use of permanent magnets for pain relief. We argue that this conclusion is unwarranted if the Static Magnetic Field dosage was inadequate or inappropriate for the clinical condition treated”. Can you imagine someone taking paracetamol to lower cholesterol and when it didn’t work, claim that all drugs are useless?
If a drug does not target the exact mechanism at the right dose, then it will be ineffective. Magnets are no different and the 7 points above describe the variations.
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