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[2008 updates are highlighted in red]
| Description: |
There are two main forms of unconventional therapy with electromagnetic fields: static, permanent magnets and pulsed electromagnetic fields. Static magnetic therapy involves the use of magnetised devices such as bracelets, belts, and mattress pads. Pulsed electromagnetic field therapy, which has been more extensively studied in MS than static magnets, uses devices that produce pulsing, electromagnetic fields at a specific frequency. In one MS study, devices with a strong, pulsing magnetic field were placed on the spine. In other studies, small devices with weak, pulsing magnetic fields were placed on the legs or specific acupuncture points. |
| Rationale: |
Multiple mechanisms have been proposed to explain possible therapeutic effects of magnetic fields in MS and other conditions. With strong magnets placed on the spine, it has been proposed that the magnetic field activates nerves in the spinal cord in such a way that there is a decreased tendency towards spasticity. For weaker magnetic fields, it is generally claimed that there are disease-associated electrical imbalances and that these can be corrected with magnetic therapy. It is believed that devices placed on acupuncture points may have acupuncture-like effects, such as altering the release of pain-relieving chemicals (opioids) in the body. Other effects have also been proposed, including activation of the sympathetic skin response, alteration of the flow of electrically charged atoms (such as calcium) through channels in the membranes of different cells in the body, alteration of the levels of a hormone, melatonin, and modulation of immune system cells.
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| Evaluation: |
There have been four placebo-controlled clinical trials of pulsed electromagnetic therapy in MS. Three of these have involved weak magnetic fields; one involved strong magnetic fields applied to the spine. In these studies, the effect of therapy on various MS symptoms was assessed. In the study of strong magnetic fields applied to the spine, spasticity was specifically evaluated and was found to be significantly decreased in the treated group compared to the placebo group. In the three studies with the weaker devices, beneficial effects on spasticity were found in some but not all studies. Similarly, in some but not necessarily all studies, improvement was noted in other MS symptoms, including pain, bladder function, hand function, fatigue, and quality of life. Given the variable findings and lack of rigour in some of these studies, further investigation is needed to clarify whether this therapy has definite beneficial effects. In addition to these clinical trials involving groups of people with MS, there are case reports in which magnetic therapy has improved various MS symptoms in individuals with MS. It is difficult to make conclusions from these studies because each report involves only a single person. |
| Risks: |
Short-term use of magnetic field therapy is usually well tolerated. The long-term effects of this treatment have not been investigated. Treatment with a strong magnet on the spine may produce dizziness and a band-like sensation around the torso. The weaker devices may cause headaches. Pregnant women and people with pacemakers or other electronic medical devices should consult with their physician before using these devices. Devices with a weak magnetic field are of low-moderate cost. Devices with a strong magnetic field are for experimental use and are not generally available.
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| Committee opinion: |
In the opinion of the Committee, pulsed electromagnetic field therapy is a low-moderate cost, generally well-tolerated therapy. Several MS clinical trials of variable quality have produced suggestive results, especially for spasticity. Further studies are needed to determine if this therapy has definite therapeutic effects in MS. |
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