Tinnitus is the medical term for any noise, such as ringing, hissing or roaring that people hear in one ear, both ears or in the head that has no external source. It’s estimated that six million people in the UK (around one in 10) are affected by it to some degree, but although people can get help in managing their tinnitus, there is currently no cure.
Tinnitus in adults is largely thought to be a result of ageing and/or exposure to loud sounds that damage the ear and ultimately cause changes to the central auditory system (the ‘hearing brain’). It’s especially distressing for some people, and may exacerbate or be exacerbated by anxiety, stress or depression. A link has been suggested between tinnitus and the serotonergic system, a nerve signalling system in the brain centred on a molecule called serotonin, that is involved in anxiety, depression, attention, stress and neural plasticity (reorganisation of the brain, such as when learning). It is also known that loud sound exposure can change the activity of this system in the hearing brain. However, not all people who are exposed to loud noise develop tinnitus or tinnitus-related distress. It could be that people simultaneously experiencing stress or other negative emotional states before or during tinnitus onset may be especially at risk of their tinnitus becoming troublesome. Therefore, research into how changes in the serotonergic system contribute to tinnitus and the emotional response to tinnitus will help us to better understand the biological basis of tinnitus. It could also help us to understand what predisposing factors can increase the likelihood of someone developing tinnitus, or developing severe tinnitus, and provide important information for testing new potential treatments.
In this project, the researchers will investigate the link between stress, emotional states, and tinnitus in an animal model of tinnitus and test a new, targeted drug intervention for its ability to treat tinnitus. They will study a specific protein, a serotonin receptor, which is involved in the serotonergic system to uncover its role in tinnitus and whether it makes a good target for drugs which can block or silence tinnitus.
Treatment for tinnitus is often expensive, protracted, and ineffective. A simple, cost-effective method of preventing or treating tinnitus would improve the lives of millions of people worldwide. The research from this project will add to our knowledge of the factors that contribute to the development of tinnitus and test the effectiveness of potential medicines, which could ultimately lead to the development of a drug treatment for tinnitus.