Thursday March 4 2010
Migraines can be devastating
A handheld device could ‘zap away’ headaches according to several newspapers. They say that the device, which delivers a magnetic pulse to the back of the head, could be an alternative to drug treatments for sufferers.
The news is based on a well-conducted randomised controlled trial and has found promising results when using a ‘single-pulse transcranial magnetic stimulation’ device to treat people who frequently suffer from migraine with visual distortions (aura). Within two hours of the onset of symptoms more people were pain-free when using the handheld device than those who had used an identical dummy device.
Although the study has reliable results, there are some points to consider when putting these findings into context. Importantly, the results will need to be verified in larger trials that directly compare the technology to other active treatments for migraine, principally medication. Therefore, the news reports are premature in announcing this treatment as an ‘alternative’ to pain medications. Further issues of optimal use, effectiveness and safety also need to be explored when further researching this promising technology.
Where did the story come from?
This research was conducted by Dr Richard Lipton and colleagues from Einstein College of Medicine, New York and other institutions across the US. The study was funded by Neuralieve, the medical technology company that makes the prototype device being tested. The study was published in the peer-reviewed medical journal The Lancet.
What kind of research was this?
This was a phase 2 randomised, ‘sham’-controlled trial testing the use of a prototype ‘single-pulse transcranial magnetic stimulation’ (sTMS) device using magnetic fields to treat certain types of migraine. The study was termed a ‘sham trial’ as it compared a real device against an identical mock device that actually performed no function.
A randomised controlled trial is the best way of examining the safety and efficacy of a treatment. However, results of this trial will need follow-up in larger phase 3 trials that compare sTMS use to other active treatments for migraine (eg replace the sham sTMS device with suitable drugs) and in larger groups of people.
News coverage has generally reflected the findings of this well-conducted trial, although most reports have jumped too far ahead in hailing this as a new treatment for migraine ‘at the press of a button’. The current stage of this research, plus the fact that it hasn’t been compared to any active treatment, mean that questions still remain over its safety and efficacy.
What did the research involve?
This research was carried out at 18 different locations across the US and studied people who experienced migraines accompanied by aura - visual distortions that precede the pain of migraines. Aura symptoms usually last less than an hour and can include visual disturbances (such as flashing/flickering spots of lights, zigzag lines or even temporary blindness), numbness, tingling sensations and slurred speech.
All eligible adults met diagnostic criteria of having at least 30% of their migraines accompanied by aura. Their migraines also had to occur at least once a month and to be associated with moderate or severe headache in 90% of those attacks. People were excluded if their migraine was suspected to be caused by, or associated with, overuse of painkillers, use of other medications, or underlying disease or trauma.
Before the treatment phase began, the recruited participants were trained in the use of an electronic headache diary, which they used for one month to verify that they had a suitable diagnosis of migraine for the trial. Sixty-six people dropped out in this phase, after which the remaining 201 individuals were randomly allocated by computer to either sham stimulation (99 people) or sTMS (102 people). Training was given in the use of the devices before the trail.
The sTMS machine tested was a handheld device that could be positioned against bone at the base of the skull. It delivers two magnetic pulses, 30 seconds apart, when the ‘treat’ button is pressed. The ‘sham’ stimulator device was identical to the real device, even buzzing and vibrating in the same manner. Neither researchers nor participants knew which device each person was using.
Participants were instructed to treat up to three attacks over a three-month period at the onset of aura. The main outcome was being pain-free within two hours of the attack, and with secondary outcomes being no difference between the sTMS device and sham device in terms of reports of symptoms of nausea, oversensitivity to light, and oversensitivity to sound within two hours of the attack. All participants were allowed to use their usual migraine medication throughout the trial.
What were the basic results?
The researchers excluded the results on 37 people who did not treat a single migraine attack during the trial. This left 164 patients (82 sTMS and 82 sham). Significantly more people treated with sTMS were pain-free within two hours (39% v 22%; 17% difference, 95% CI 3 to 31%).
At 24 and 48 hours after using the device, sustained pain-free response rates were also better in the treatment group.
There were also no differences between the sTMS and sham groups in rates of associated nausea, sensitivity to light, or sensitivity to sound. No device-related serious adverse effects were observed.
How did the researchers interpret the results?
The researchers conclude that early treatment of migraine with aura using sTMS resulted in increased freedom from pain at two hours compared with sham stimulation, and sustained absence of pain at 24 and 48 hours. They say that sTMS this could be a promising new treatment for migraine with aura.
This well-conducted, double-blind, randomised controlled trial has found promising results when using single-pulse transcranial magnetic stimulation (sTMS) to treat people who frequently suffer from migraine with visual aura. Within two hours of the onset of symptoms, more people were pain-free when using the handheld device than those who had used an identical ‘sham’ device.
Although the study has reliable results, there are a couple of things to consider when putting these findings into context:
- This was a phase 2 trial, which has so far compared sTMS only with no treatment in a relatively small number of people (164 completed the study). Results will need follow-up in larger phase 3 trials that compare sTMS to other active treatments for migraine (eg actual drugs rather than sham sTMS) and in larger groups of people.
- People in this trial were allowed to use medications to treat their migraine as normal, so at this stage it is difficult to extract the extent of the effect that sTMS alone is having, for example how people would feel if they used sTMS as their sole treatment for migraine. Therefore, the news reports are premature in announcing this treatment as an ‘alternative to pain medications’.
- Although no significant adverse effects of this device were observed, a greater number of people who had used this device for much longer than three months (the period of this study) would need to be observed in order to see whether there were any longer-term adverse effects or health risks of sTMS.
- As the researchers say, they have not yet explored the possible range of sTMS doses that could be given, or the optimum timing of treatment (at what stage in the headache, for example).
- The device at the current time would only be suitable for people who experience migraine with visual aura.
Overall, the findings of this study are promising, and further trials are awaited.