Benefits and risks

Information for the public

When NICE looked at the evidence, it decided that although the procedure can reduce pain and the number of migraine attacks it was not clear how often it should be used or what the best combination of magnetic pulses was. It decided that although the procedure was safe to use in the short term, there was not enough evidence about how safe it is in the long term or when used often. The 5 studies that NICE looked at involved a total of 332 patients.

Generally, they showed the following benefits:

in a study of 164 patients who had the single TMS procedure or a 'sham' procedure during a migraine attack, the 82 patients who had the TMS procedure found that their pain improved more after treatment than the 'sham' group
in a study of 51 patients whose migraines were not helped by drug treatment, the repeated TMS procedure reduced the number of migraine attacks by half for up to 4 weeks
in a study of 27 patients, of whom 14 had the TMS procedure and 13 had a 'sham' procedure, the number of migraine attacks and the numbers of hours and days with migraine over an 8-week period were reduced within both groups, but this was less likely to have happened by chance in the TMS group.

The studies showed that:

there were no serious risks associated with having the procedure
a very few patients had slight dizziness, drowsiness, tiredness, muscle tremor causing difficulty standing, irritability, vivid dreams and sensitivity to sound, none of which needed treatment.

NICE was also told about some other possible risks:

short-lasting muscle contraction
pain where the pulses are given
effects on hearing.

In theory, other risks include local scalp irritation, mood disorders, cognitive impairment, triggering of epilepsy or seizures during treatment and permanent neural changes.

If you want to know more about the studies see the guidance. Ask your health professional to explain anything you don't understand.