Migraine sufferers could receive help in the form of a machine that fires a magnetic pulse to the back of the head.
The hand-held device was found to relieve pain for up to 48 hours, with no serious side-effects reported and no aggravation of associated symptoms. The device applied magnetic pulses to the scalp of volunteer patients suffering attacks of migraine with aura.
Researchers randomly assigned 201 patients to receive treatment with either the single-pulse transcranial magnetic stimulation (sTMS) device or a fake machine. The patients were taught how to use it themselves in applying two pulses 30 seconds apart as soon as possible after aura symptoms.
The researchers said of the 164 patients who treated at least one attack, 39% from the sTMS group were pain free after two hours compared with 22% of the "sham" group.
The "aura" migraine is characterised by neurological effects before the headache, such as lights or lines in front of the eyes, visual "blank spots", and tingling or numbness. It affects about 20% to 30% of migraine sufferers.
Findings from the study, led by Dr Richard Lipton, from the Albert Einstein College of Medicine in New York, are in the journal The Lancet Neurology.