This three-year project is led by Dr Raj Shekhawat at Flinders University, Adelaide, Australia. It will run from January 2021 until January 2024.
Tinnitus is the perception of sound in the absence of any external sound source. It is commonly described as a ringing, buzzing, hissing, whistling or humming sound in the head or ears. It is very common – 1 in 7 adults have tinnitus. Many more experience tinnitus occasionally. Tinnitus can have a severe impact on someone’s quality of life, causing anger, frustration, problems sleeping, depression and anxiety.
Treating tinnitus costs the NHS around £750 million per year. Currently, the most effective treatments are psychological management approaches which aim to reduce tinnitus-related distress. There is no cure for tinnitus, and to date, no treatment that achieves a consistent long-term reduction of the tinnitus sensation.
Non-invasive brain stimulation techniques have been tested for their ability to treat a number of neurological conditions. They have shown promise at being able to temporarily suppress tinnitus. They work by altering activity in the brain to change how it functions, particularly in those parts of the brain thought to be responsible for tinnitus perception. Dr Shekhawat has conducted a number of preliminary studies to investigate whether a specific type of non-invasive brain stimulation, ‘transcranial direct current stimulation’, or tDCS, is effective in treating tinnitus. In these studies, some participants experienced complete silencing of their tinnitus for up to three days.
This project is based on and will extend Dr Shekhawat’s previous work on tDCS as a treatment for tinnitus. Specifically, he will investigate a form of tDCS, called High-Definition tDCS, which will allow him to stimulate certain brain regions more specifically.
He will investigate whether High-Definition tDCS can reduce tinnitus loudness and annoyance over an extended period of time. His research will investigate whether stimulating specific regions of the brain can suppress tinnitus more effectively, and for longer.
The research team will carry out two studies. In the first study, they will test the effect of stimulating two regions of the brain, the auditory cortex and the pre-frontal cortex, either separately or together, on tinnitus. They will test this in people with tinnitus, and compare it to results from people who receive ‘sham’ stimulation, to see which treatment strategy is the most effective and long-lasting against tinnitus.
In the second study, they will investigate the changes that happen in the brain when High Definition tDCS is used to reduce tinnitus. They will use the most effective treatment strategy, identified from their first study, to do this, again in people with tinnitus. They will also carry out brain imaging studies to assess these changes in more detail.
As part of this project, the researchers will conduct one of the first trials of High Definition tDCS for tinnitus treatment in the world. The results will increase our understanding of the processes underlying tinnitus. They will also help to establish whether High Definition tDCS could be used in the clinic as a way to treat tinnitus effectively.