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Health See other Health Articles Title: Transcranial Magnetic Stimulation FDA Approved for Migraine with Aura Introduction On December 13, 2013, the US Food and Drug Administration (FDA) approved the Cerena Transcranial Magnetic Stimulator for the treatment of pain caused by migraine headaches with aura. A 2009 YouTube video illustrates the use of an earlier version of the device, referred to as the "Migraine Zapper," by Yousef Mohammed, MD, an investigator at Ohio State University. The FDA approved model is more formally known as the “Spring TMS Total Migraine System,” marketed by eNeura Therapeutics, Sunnyvale, CA. Magic Magnets For hundreds if not thousands of years, people have been fascinated with the potential curative powers of magnetic energy. In the 16th century, Paracelsus used magnets to treat a variety of illness. In 18th century Vienna, Dr. Anton Mesmer became famous for his imaginative theory of the therapeutic powers of “animal magnetism.” Even today, magnets of various shapes and sizes are worn to vanquish all sorts of ailments such as infection, inflammation, pain, impaired blood circulation, low energy and more. The developers of the Spring TMS Total Migraine System are to be congratulated for taking a dramatic departure from other promoters of magnet therapies and going the distance to perform a legitimate, sham controlled, randomized trial conducted by leading headache experts. Clinical Trial The two-phase clinical trial initially included 267 adults (aged 18-68) who had a visual aura preceding at least 30% of migraines followed by moderate or severe headache in more than 90% of attacks (Lipton et al. 2010). After 66 patients dropped out during phase one, 201 patients were randomized to sham (N=99) or magnet (N=102) treatment. Of these, 37 did not treat a migraine attack, leaving 164 patients; 82 who actually treated a migraine with magnet stimulation and 82 who received sham stimulation. Of those treated with magnetic stimulation, 32/82 (39%) were pain free after 2 hours compared to 18/82 (22%) who received sham stimulation, a 17% gain (p=0.0179). There was “noninferiority” (no benefit) for associated symptoms such as nausea, photophobia and phonophobia. Adverse effects were infrequent with active stimulation (14%), and none of the patients discontinued the study because of adverse effects. Treatment An instructional video appears on the manufacturer’s website, featuring an attractive woman carrying the device in her capacious handbag. The battery powered stimulator is significantly larger than an average paperback book, but smaller than a copy of Adams and Victor. When the patient senses the beginning of a headache, she sits on the couch and an automated touchscreen walks her through the simple treatment procedure. The device records the number of treatments and allows the patient to document her response in an electronic diary that can be uploaded to the internet. The log and diary are important features that will facilitate care when the patient sees her neurologist for follow up. Mechanism of Action According to the manufacturer’s website, “The magnetic field induces very mild electrical currents in the brain tissue to excite and depolarize neurons in the brain. This process is thought to interrupt the abnormal electrical activity associated with migraine and cortical spreading depression (CSD).” As such, the mechanism of action is consistent with our current understanding of migraine pathophysiology, but it’s a little thin on detail. It would be interesting to learn more about exactly which populations of neurons are depolarized by transcranial magnetic stimulation (TMS) and how they respond over time. Cautions The device should not be used in those with seizures or a family history of seizures. It should be used no more than once every 24 hours. Obviously, patients with metal in the head, neck, or upper body and those with a pacemaker or deep brain stimulator should not use it. Long-term Effects? What are the long-term effects of regular stimulation of the brain with “very mild electrical currents?” How will this affect the future frequency of migraine headaches? Are there any long term effects on cognition, personality, or other brain functions that may present after months or years of therapy? Comments from the Lead Investigator Richard Lipton, MD, Edwin S. Lowe Professor and Vice Chair of Neurology, Albert Einstein College of Medicine, Bronx, NY, was the lead author of the pivotal trial. Dr. Lipton was kind enough to respond to questions in an email interview. Dr. Lipton observed, “Transcranial magnetic stimulation is not the same as magnet therapy. Both the FDA and National Institutes of Health have reviewed TMS for other indications, and it is considered a very low risk procedure, even when given in much higher doses than those used for migraine. The device delivers two pulses of a magnetic field. When people use TMS to treat depression they get thousands of pulses on a daily basis for weeks. A single day of depression treatment carries more exposure to magnetic fields than a year of intermittent treatment with TMS and has been shown to be safe.” Good Treatment Candidates In terms of who should use the device, Dr. Lipton advised, “There has to be a reason to use the device rather than an oral medication. Common reasons could include: 1) Lack of effectiveness of oral medications, 2) Side effects to oral medication that limit their use, 3) Contraindications to certain classes of oral medication. For example, triptans should not be used in people with cardiovascular events (heart attack or stroke) or in people at high risk for heart attack and stroke, 4) NSAIDS should not be used in people with active peptic ulcers and should be used cautiously in people with a history, 5) Very frequent headaches, which make medication taking less desirable because of the risk of side effects or medication overuse headache, 6) A strong patient preference to avoid drugs.” Future Research Dr. Lipton added, “The big questions are: 1) Does the device work in migraine without aura as well? My best guess is yes, but there is no rigorous proof of that. 2) Does frequent use of the device work only as an acute treatment or does it prevent migraine? US studies post-approval to address these questions and analysis of the ongoing UK study, where the device is already approved, are planned.” Potential for Misuse Because the device is simple to use, the possibility exists that children, adolescents, or others might willfully misuse it. Perhaps a log-in code, such as those on smartphones or electronic tablets, should be added to the start-up menu. Unauthorized users will leave a trail of evidence in the automatic log, which should be regularly reviewed. Conclusions The results of the clinical trial were statistically significant but modest, demonstrating a 17% gain in the percentage of patients pain-free at 2 hours. It will be of great interest to learn whether the device works in the even greater number of patients who have migraine without aura, and also whether it has any value in migraine prophylaxis. The device represents an FDA approved alternative for those who don’t respond to or can’t tolerate conventional treatment. In terms of patient preference, it is not clear how many patients would prefer to carry around a high tech gadget rather than swallow a couple of pills at the first sign of headache. Comparative treatment trials, preferably with conventional abortive treatments such as aspirin, NSAIDs, and triptans, as well as long-term safety studies, should be performed before migraine sufferers embrace the awe-inspiring power of a magnetic pulse to treat their migraines with aura. References Lipton RB, Dodick DW, Silberstein SD et al. Single-pulse transcranial magnetic stimulation for acute treatment of migraine with aura: a randomized, double-blind, parallel-group, sham-controlled trial. Lancet Neurology 2010;9:373-80. Post Comment Private Reply Ignore Thread
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