This article was first published on 29-10-2025.
She still receives several emails a week, says Jana Devos, PhD researcher at the Faculty of Health, Medicine and Life Sciences (FHML) and psychologist at the MUMC+ audiology centre. Emails from people who want to sign up to be test subjects for a potential treatment for tinnitus using an electrode deep in the brain. The fact that the call was launched back in 2020 and the website explicitly states that participation is no longer possible doesn’t seem to deter them.
It shows how many people there are desperately searching for a cure for the incessant ringing, buzzing or hissing noise in their head, says Devos. According to research done at Maastricht in 2022, about 14 per cent of people around the world suffer from tinnitus, which accounts for millions of people in the Netherlands alone. Prolonged exposure to loud noise – when going out, at work, or listening to music on headphones – is a known cause, but other causes include infection, head trauma, or age-related hearing loss.
Plenty of people are not badly affected by tinnitus. “Many don’t even go to a doctor, or providing information about tinnitus is enough to help them,” says Mark Janssen, associate professor at FHML and neurologist and clinical neurophysiologist at the MUMC+. But for a small percentage of adults – hundreds of thousands of people in the Netherlands – it is worse and “can even lead to sleep disorders, anxiety, depression”.
This group usually ends up going to hospital. In some cases, a hearing aid solves the problem, while for a large number, cognitive behavioural therapy offers some relief. One treatment developed by researchers at Maastricht has been a standard course of treatment for a few years now, says Devos. “You teach people how to cope with tinnitus, but you don’t reduce the noise they’re hearing.” The latter is possible through a cochlear implant. “But that is only an option for tinnitus patients who suffer from extreme hearing loss,” says Janssen.
Unfortunately, this means there is a group left over for whom nothing helps, he says. “In absolute terms, you’re talking about a significant number of people.” They are the ones who will desperately seek out treatments that have either been insufficiently proven to work, or proven not to work, from noise to cover the tinnitus to stimulation of the tongue. “Some people travel all around the world in search of a cure, spending vast sums of money.”
Overactive brain
But there may yet be hope. The research project at Maastricht using an electrode in the brain, for which Devos sent out a call for test subjects in 2020, and which Janssen is also involved in, is nearly finished and the results so far are optimistic.
It is focused on a method called deep brain stimulation (DBS). An electrode is placed in the brain via a small hole in the skull and is aimed at a specific area. A subdermal battery sends electric pulses towards the electrode, which influences the brain activity in that area. This has been successfully used on people with Parkinson’s disease. “When you turn it on, tremors in the patients stop almost immediately,” says Janssen.
There has long been a theory that this could also be used to mute the noise experienced in tinnitus. Although the underlying mechanism is not yet completely understood, it is clear that a part of the brain is overactive, says Janssen. “The thought is that there is always some hearing loss involved, which means the part of the brain that processes sound receives less information via the cochlear nerve.” The brain then tries to compensate for this lack of information by ‘making it up’, which causes the tinnitus. “You might be able to suppress that activity by stimulating a specific area of the brain. We are the first and only research team in the world researching this approach.”
Significant decrease
After earlier studies in Maastricht using rats showed positive results, five years ago, the project was ready to move on to people. “It is always an exciting step,” says Janssen. “We know that DBS is safe, but it is a different part of the brain than for, say, Parkinson’s, with potentially different side effects. Stimulation might increase hearing loss or produce new sounds.”
The results of research on four test subjects, which Devos successfully defended in her PhD thesis last Tuesday, will likely soon be published in a “leading academic journal”, says Janssen. Until that time, he is hesitant to provide too many details – the work is still being peer reviewed – although he does hint that the side effects may not be too bad, and that as hoped, some of the subjects reported a significant decrease in symptoms. “Don’t think of it as an immediate improvement like with the tremors in people with Parkinson’s disease, it’s more like months of gradually retraining the neural network.”
What Janssen does want to say, is that the research “has above all shown that the procedure is safe and feasible. Further research involving a greater number of test subjects will be needed to determine whether it is actually effective, starting with a trial of sixteen people. We are currently looking for funding for that project.” An unexpected result of the research may be a better understanding of what exactly causes tinnitus. “The good thing is that you are in the brain, those measurements are valuable. It could lead to ideas for other, less invasive procedures.”
Evening news
However, all that is for another day. First will be the publication of the most recent research. Janssen expects the inbox will be flooded with hundreds of emails again. “The same thing happened three years ago, too, when we published the results after a trial with one subject – lots of media attention, and the NOS even considered reporting on the item on the evening news.”
It is also a question of tempering expectations, he says. Even if DBS is used to treat tinnitus, it will only be an option for the severest cases. “It’s very intensive and it does involve inserting a foreign object into the brain. There is always a chance of bleeding or infection, and those risks have to be weighed against the symptoms.” According to Devos, the most important message remains as ever: “Prevention is better than cure.”