An article published Online First and in the April edition of The Lancet Neurology reports that a new hand-held device that delivers a magnetic pulse to the back of the head could be a promising non-invasive, non-drug treatment option for patients with migraine. This device offers efficient pain relief for up to 48 hours after treatment in some patients with migraine with aura. Treatment has to be given at the onset of symptoms. It does not cause any serious side-effects.

There are two major types of migraine:

• migraine without aura
• migraine with aura

In migraine with aura, a variety of focal neurological features occur in association with the headache, usually beginning before the onset of pain. These include visual symptoms such as spots of light, zigzag lines, and regions of visual loss, as well as non-visual symptoms including tingling and numbness, and weakness and difficulties with language.

There are two types of transcranial magnetic stimulation (TMS):

• Single pulse (sTMS): In sTMS, used in the present study, individual magnetic pulses are applied.
• Repetitive TMS (rTMS): In rTMS a series of pulses is used. rTMS has been approved by regulatory bodies for use in diagnostic testing and for the treatment of depression. There is therefore a large body of data supporting the safety of TMS with much higher exposures than used in the present study. The device used in this study is portable and suitable for self-treatment outside medical settings.

There is confirmation that single-pulse transcranial magnetic stimulation (sTMS) might disrupt the electrical events in the brain that underline migraine aura. Earlier small-sized studies indicate that sTMS reduces migraine pain and that it is well tolerated. But, previous trials used large and expensive devices not suitable for use outside a clinic. This made it difficult to verify if the effect of TMS was authentic.

To test the limitations of the earlier findings, Richard B Lipton from the Albert Einstein College of Medicine, New York, USA, and colleagues carried-out a randomized, sham-controlled trial. They assessed the safety and effectiveness of a new, hand-held sTMS device suitable for home use, in the treatment of migraine with aura. The trial involved an identical device designed to deliver an inactive (sham) impulse to ensure patients and investigators were masked to treatment. Both active and sham treatment was associated with a clicking sound and vibration of the device to maintain blinding. Blinding was successful as demonstrated by the fact that 80 percent of patients in both groups thought they received active sTMS. A total of 201 patients were randomly assigned to sham stimulation (99) or sTMS (102). They were instructed to treat up to three attacks over three months while experiencing aura. They were required to record pain and associated symptoms before and at regular intervals after treatment.

Results indicated that sTMS was considerably more efficient than placebo for the treatment of migraine with aura. More patients were pain free at follow-up intervals of 2, 24, and 48 hours. They were free of headache recurrence. In addition, they did not need rescue medication, compared with sham stimulation. Out of the 164 patients who treated at least one attack, 39 percent in the sTMS group were pain free 2 hours after treatment compared with 22 percent in the sham group. This results in a therapeutic gain of 17 percent.

Furthermore, sTMS treatment did not intensify associated symptoms. Also, it was non-inferior to sham stimulation for:

• the improvement of nausea
• photophobia which is an excessive sensitivity to light
• phonophobia which is a heightened sensitivity to sounds

More significantly, sTMS treatment was well tolerated. There were no device-related serious adverse events reported. Also, the prevalence and severity of side-effects was low and comparable between the two groups. In addition, patients hardly ever experienced errors when using the device. They rated it an average 8 out of 10 for user-friendliness.

The authors mention: "Although the exact mechanisms of migraine remain under study, administration of sTMS in people with migraine with aura decreases progression of the attack in some individuals…and could be a promising acute treatment." They say in closing that further research is required in order to examine the range of sTMS doses. The optimum timing of treatment and cost effectiveness also need to be established.

In an associated note, Hans-Christoph Diener from University Hospital Essen in Germany comments that these findings demonstrate that: "the use of TMS could be a major step forward in the treatment of migraine with aura, particularly in patients in whom presently available drug treatment is ineffective, poorly tolerated, or contraindicated."

"Single-pulse transcranial magnetic stimulation for acute treatment of migraine with aura: a randomised,double-blind, parallel-group, sham-controlled trial"
Richard B Lipton, David W Dodick, Stephen D Silberstein, Joel R Saper, Sheena K Aurora, Starr H Pearlman, Robert E Fischell, Patricia L Ruppel, Peter J Goadsby
DOI: 10.1016/S1474-4422(10)70054-5
The Lancet Neurology

Stephanie Brunner (B.A.)