The top research priority highlighted by people with tinnitus is always to find a treatment to stop it. Unfortunately, we are still a long way from achieving a cure for tinnitus. A major limiting factor is that we do not have a reliable way to ‘objectively’ measure tinnitus – a way that isn’t affected by a personal judgement, either by the person with tinnitus or the person measuring it. This lack of an objective test makes it very difficult to study tinnitus effectively, or to measure any changes in people’s tinnitus following treatment. This means that we cannot reliably monitor the effectiveness of tinnitus treatments.
In theory, if a person has tinnitus, the tinnitus sound will influence how they hear actual sounds present in their environment. For instance, imagine a sequence of short sounds playing one after the other with silent gaps in between. The tinnitus sound will “fill in” the silent gaps, and so the person will hear a single ongoing sound. This ongoing sound would also change intermittently in pitch, character and/or loudness, because the real sounds being played would be alternating with the tinnitus sound.
This change in a sequence of sounds (i.e. real sounds alternating with the tinnitus sound) can also influence how the brain processes sound. This can be seen in changes in the electrical activity of the brain, which is easily measurable from a person’s scalp. Initial work by Dr Sedley has shown that measuring changes in brain activity when someone is listening to a sequence of sounds can tell the difference between people with tinnitus and people who do not have it. Thus, it shows promise as an objective way to measure tinnitus in people, as well as in animals, which is vital for developing effective treatments.