Treating the brain with magnets went mainstream a few years ago, when the technique proved successful at relieving major depression. Now the procedure, repetitive transcranial magnetic stimulation (rTMS), shows promise for another mysterious, hard-to-treat disorder: chronic pain.
Until now, pain seemed out of reach for rTMS because the regions involved in pain perception lie very deep within the brain. The other disorders helped by rTMS all involve brain areas close to the skull. To treat depression, for example, a single magnetic coil directs a magnetic field at the dorsolateral prefrontal cortex, a region of the brain's outer folds. When aimed at different areas of these outer folds, rTMS improves the motor symptoms of Parkinson's disease, staves off the damage of stroke, lessens the discomfort that follows nerve injury and treats obsessive-compulsive disorder. The magnetic field affects the electrical signaling used by neurons to communicate, but how exactly it improves symptoms is unclear—scientists suspect rTMS may redirect the activity of select cells or even entire brain circuits.
To extend the technique's reach, David Yeomans, a neuroscientist at Stanford University, and his colleagues used four magnets rather than one and employed high-level math to steer the resulting complex fields. Their target was an area called the anterior cingulate cortex (ACC), an area active in the experience of all types of pain, regardless of its source or nature.
The researchers aimed the magnetic impulses at the ACC of healthy volunteers for 30 minutes. Immediately afterward, subjects underwent a PET scan of brain activity. During the scan, subjects reported minute-by-minute pain sensations from a hot plate applied to their arm. After rTMS, subjects rated their pain nearly 80 percent lower than they had before treatment, and the PET scan revealed blunted activity in the ACC.
Next the researchers tested the treatment on chronic pain in people with fibromyalgia, a mysterious pain syndrome that causes pain and tenderness all over the body. Patients received a daily dose from the magnets for four weeks and saw a reduction in their daily pain by almost half, which lasted for four weeks beyond treatment.
The study, presented at last October's meeting of the Society for Neuroscience in New Orleans, shows the potential of rTMS for many kinds of pain. The procedure has become increasingly common and available since 2008, when the Food and Drug Administration approved it for treating major depression. “More psychiatrists are bringing it into their armamentarium,” Yeomans says. Now that it appears this noninvasive technique “can affect pain without putting new molecules into your body,” he adds, relief may be close for people for whom drug therapies have failed or simply do not exist.
$300 - Cost of a typical transcranial magnetic stimulation (TMS) session. TMS therapies often include 20 to 30 sessions, at a total cost of between $6,000 and $10,000.
12/08 - Date the FDA approved TMS in the U.S. to treatmajor depression in adults who had failed to improve on an antidepressant regimen. Canada had granted the same approval six years earlier.
1 - Number of conditions TMS is approved to treat: major depressive disorder. Research suggests the technique can also help people with post-traumatic stress disorder, bipolar disorder and Parkinson's disease, among other ailments.
387 - Number of recent clinical trials testing TMS for a variety of conditions, including schizophrenia, anorexia, Alzheimer's disease, autism and cerebral palsy.
1985 - Year TMS was first developed and tested. Anthony T. Barker of Royal Hallamshire Hospital in Sheffield, England, used the machine to noninvasively stimulate the cerebral cortex
This article was originally published with the title Blunting Pain with Magnets.
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6 Comments
Add CommentTranscranial direct current stimulation (tDCS) uses a tiny amount of electricity from a portable stimulator powered by a 9 volt battery via sponge electrodes to provide effects similar to TMS. An off-label use of an FDA certified device, tDCS is easy to do, without side effects and can be done by the patient at home. tDCS is safer than TMS, provides a more robust response than TMS and is a fraction of the cost of TMS.
Reply | Report Abuse | Link to thisThis concept has been around for many years. Back in the 1950's, a company sold beanie type magnetic hats through tiny magazine and newspaper adds. The hats came with a number of button sized magnets that could be moved around into various small pockets. The pockets were labeled so the user could choose the specific results he or she was seeking. I recall enhanced memory was one of the many benefits claimed. I found, through many hours of experimentation, that by moving all of the magnets to either the left or right side of the hat one could exercise the opposite hemisphere much like the breathing exercises so popular in the 1980's.
Reply | Report Abuse | Link to thisDr Fugedy - there have been some interesting studies of tDCS, but to suggest it "provides a more robust response than TMS" is false. TMS is an intense, pulsed magnetic field, and the large rapid changes of magnetic field are what is required to stir electric currents in the brain tissue, which then leads to stimulation (usually disruptive stimulation) of neural activity. tDCS is a mild electric current which can only affect the brain by passing through the small openings of the skull or the cranial sutures. So the tiny current at the scalp induces minuscule currents inside the skull, and negligible current at the cingulate, which is a good two inches down from the surface. Suggesting this is more robust than TMS is demonstrably false. However, even these currents appear to have a biasing effect on cognition and some tasks, and there is some evidence that it can reduce pain and pain-associated experiences like itch. So it will be interesting to see where it goes, although the caveat with any pain-related research is the major subjective component in pain perception - "an opinion on the organism’s state of health rather than a mere reflective response to an injury," as Ramachandran put it.
Reply | Report Abuse | Link to thisAnd "littleredtop" - placing static magnets near the head has very little to do with the technology of TMS. TMS uses pulses of magnetic field (via a high-conductance electromagnet of a specific configuration) to stir electric currents in deep tissue, which doesn't occur with static magnetic fields, no matter what the intensity. So the comparison with shyster magnetic therapies is completely invalid on the basis of simple physics.
I remember reading a few years ago about TMS in the treatment of depression, but knowing some sufferers, I'm surprised we haven't heard more about it since. You'd have thought there would have been some large-scale studies by now, or given the benign nature of the intervention, more real-life trials.
Reply | Report Abuse | Link to thisI do wonder whether it's not just another one-day wonder, over-hyped with it's effects exaggerated.
With a price tag in the thousands of dollars this isn't exactly cheap. As with any therapy, be it pharmaceutical, surgical or behavioral, there are long term side effects. What these side effects will turn out to be is still unknown. Maybe they will all take so long to manifest that it will be a non-issue. Maybe they will all be benefits. The thing is that we won't know until there are hundreds of thousands of people many decades past their initial treatment.
Reply | Report Abuse | Link to thisThis is an extremely dangerous procedure that should only be performed with the patient's consent and with their ability to OPT OUT at any time from any such life threatening experimentation immediately.
Reply | Report Abuse | Link to thisElectrical stimulation of any kind places the patient at risk of seizures, strokes, and heart attack.
Many research academies and universities believe they have the right to experiment on individuals from a distance without the patient's consent. It is against international humanitarian law and illegal to experiment on individuals without their consent.