Up to 15 percent of all Swedes suffer from constant wheezing, chirping or other noises no one else can hear. Some get better by themselves. Many receive help from cognitive behavioral therapy and other treatments, but individual patients experience no relief at all.

"We have treated the sickest of the sick," says Steven Cheung, professor of ear, nose and throat diseases at the University of California, San Francisco, USA.

Used against Parkinson's disease

His research group operated electrodes in the heads of three men and two women with tinnitus. This method is called DBS (deep brain stimulation) and is a kind of pacemaker for the brain. It is well established against Parkinson's and some neurological motion disorders.

The new study is based on a random discovery a few years ago: A patient was given electrodes against Parkinson's disease. She also had tinnitus - which decreased after the procedure. Surgeons concluded that the relief was due to a blood vessel rupturing during surgery and damaging a bundle of nerve cells deep inside the brain. Follow-up experiments showed that even electric current in the same bundle can relieve tinnitus.

All but one got better

The five patients who had been operated on so far had to estimate their problems before, during and after the procedure. All but one got better, according to a report in the journal Journal of Neurosurgery .

Everyone had almost unbearable problems from the beginning, and the researchers emphasize that surgery can only be considered in the most difficult cases.

Patric Blomstedt, brain surgeon at Norrland University Hospital, has taken note of the results. He points out that in most cases the effect was quite moderate, and that more research is needed to find out how much is due to placebo.

- But with that said, I think they can be something on the tracks. It looks exciting, he says.