A drug-free treatment for migraine which, it is claimed, alleviates pain in sufferers plagued by the chronic condition was described by doctors yesterday as an "exciting innovation".

The hand-held device, which delivers a brief magnetic pulse to the back of the head, reduced the frequency of headaches in more than half of patients prescribed it in a clinical trial.

The findings were presented at the European Headache and Migraine Trust International Congress in London yesterday. They have not been peer reviewed or published in a medical journal.

Migraine affects an estimated eight million people in Britain. It is caused by an "oversensitive" brain which reacts to triggers such as fatigue, hunger, stress or the weather with a throbbing, headache, often accompanied by nausea and visual disturbances.

Specialists at migraine clinics in London, Bath, Hull, Exeter, Liverpool and Aberdeen prescribed the device to patients, of whom almost three-quarters (73 per cent) reported a reduction in pain. Almost two-thirds said associated symptoms such as nausea were improved. No figures for the number of patients involved in the trial, the source of funding or the cost of the device were available.

The Spring Transcranial Magnetic Stimulation device was developed by eNeura Therapeutics in the United States. Anna Andreou, headache research fellow in the anaesthetics, pain medicine and intensive care section at London's Imperial College, who tested the device, said it decreased activity along nerve pathways. "It is a safe, non-invasive technology," she said.

Professor Peter Goadsby, the congress joint chair and a neurologist, said: "For the many migraine sufferers whose medicines just do not do the job, it is exciting to see such an innovative, novel approach to treatment."

One patient who took part in the trials, Yasmin Bibi, said: "I have suffered migraine for nine years, tried a lot of medicines and saw different consultants to no avail. I could be completely debilitated for a whole week, needed time off work and was at my wit's end. Now the device helps me to cope."