Research news

Scientific Research
Action for Tinnitus Research is funding research into how some drugs may hold the key to treating certain kinds of tinnitus. This includes drugs that could balance the effects of the excessive release of glutamate - known to be the neurotransmitter in the inner ear.

Excessive glutamate release in the inner ear is thought to affect the way the auditory nerve actually carries signals from the inner ear to the brain.

Nerve fibres carry signals
In the human inner ear there are normally about 20,000 individual nerve fibres. These all carry very brief electrical signals to the brain as tiny 'spikes' of activity. As the inner ear senses sounds, the level of spike activity increases in those nerves that code that specific sound.

Amazingly even when it is quiet, many nerve fibres in the normal ear are busy 'spiking' away - actively telling our brain that there are no incoming sounds to deal with. Normally our brains can deal with all this activity and can tell silence from sound.

Damaged nerves cause excessive 'spiking'
Unfortunately, this normal 'spiking' activity can be changed as a result of damage caused by excessive noise or other causes. What appears to happen is that after damage to the nerve, the 'spiking' activity of some of the damaged nerves still remains above their normal level of activity.

Increased spiking activity in some nerve fibres causes our brains to think that there is sound present even when there is no external sound. Even in some otherwise normal nerves it is possible that increased nerve activity can lead to the perception of tinnitus.

Research provides better insight
What researchers would like to look at in more detail is how this increased nerve activity ties in with other clues they have about tinnitus. They would especially like to look at what drugs would be able to treat only the affected nerves whilst not affecting otherwise normal nerve fibres.

It is possible that in some tinnitus sufferers, only a few hundred or so nerve fibres out of the many thousands may be affected and involved in the tinnitus. This would then provide greater insight into the best way for doctors to tailor tinnitus therapy for the different levels and types of tinnitus.