In the UK alone, 6 million people (around one in 10 of us) have tinnitus. For 600,000 people, tinnitus causes serious anxiety and stress. While there are different ways to manage tinnitus, there isn’t yet a cure. That’s why tinnitus research is so important.
What we’ve achieved so far
Tinnitus is in the brain
Before 2000, we knew very little about which parts of the auditory (hearing) system were involved in tinnitus. This led to us funding a three-year project at Massachusetts Eye and Ear Infirmary. The research team used a brain imaging technique and discovered that tinnitus was associated with increased activity in part of the brain called the inferior colliculus.
We funded a follow-up project at UCL to investigate what this part of the brain does. Our research showed that it acts like a ‘volume control’: it amplifies activity when signals from the ear are weak, and turns activity down when signals are strong. It suggests that we could potentially treat tinnitus by developing drugs that would turn activity down in this part of the brain.
Damage to the cochlea triggers tinnitus-related hyperactivity in the brain
Research we funded in Australia has shown that damage to the cochlea caused by exposure to loud noise triggers hyperactivity in the ‘hearing’ parts of the brain. Importantly, the research also showed that if signals from the cochlea to the brain are blocked soon after the onset of tinnitus then tinnitus-related hyperactivity is reduced. But if the signals are blocked later on, there is no effect. This research suggests there may be two stages to the development of tinnitus. An initial phase, dependent on signals from the cochlea to the brain, and then a second phase, where tinnitus becomes established in the brain. Research effort is now focused on finding a way of safely blocking the signals from the ear that trigger tinnitus. This could ultimately lead to a treatment for people who have only recently developed tinnitus.
Current research projects
While we’ve made great progress, there’s still a lot we don’t know about how and why tinnitus begins. We hope the current projects we are funding will give us clues towards developing treatments for all types of tinnitus.
Stress, anxiety and tinnitus
At Johns Hopkins University in the US, we’re funding research to investigate how high levels of anxiety and stress might affect the chance of developing tinnitus and its severity. The research team is also looking at a chemical called serotonin that is found in the brain. It plays a role in anxiety and stress, and is also involved in controlling the activity of the auditory nerve. The team is testing whether drugs that change the way this chemical works can reduce tinnitus. If it does, it could lead to a new way of treating tinnitus.
Investigating the auditory nerve
The auditory nerve carries information about sound from the inner ear to the brain. The nerve is made up of neurons, which carry the electrical signal, and glia cells that maintain and support the neurons. Research has shown that failures in communication between glia and neurons can trigger conditions such as chronic pain and migraine. We’re funding a project at UCL to investigate how glia and neurons communicate in the auditory nerve, and how these processes might change when tinnitus is present. This research could suggest new ways of treating tinnitus.
Sleep and tinnitus
We’re funding a project at University of Oxford in which researchers will monitor how brain activity changes as tinnitus develops and how this activity changes when we sleep. Brain activity is very different when we’re asleep, helping us to learn and form memories. Our project will help discover whether these processes play a role in getting tinnitus. If they do, then drugs that regulate them might help treat tinnitus.
Developing an objective test for tinnitus
Measuring tinnitus is a major difficulty for researchers developing treatments. We rely on people describing their tinnitus, which is subjective. We also do behavioural tests in animals, and these may not accurately reflect tinnitus in people.
Later this year, we’ll be starting a new project in Newcastle to tackle this problem. The research team will be developing an objective ‘biomarker’ that will indicate if someone has tinnitus. To do this, the team will use a brain imaging technique called electroencephalography (EEG) to measure brain activity patterns when a person is listening to sound with silent gaps in it. If someone has tinnitus, it’s fair to assume they will not ‘hear’ the silent gaps and so will show a different pattern of brain activity. If this is successful, we would have an objective tinnitus test, which would make it much easier to test and develop new treatments.
Please support our research
None of our research would be possible without the generosity of all our supporters who are helping us bring forward the day when there will be effective treatments. Please donate today.