Somatosensory tinnitus

Somatosensory tinnitus - a special type of tinnitus is providing new clues to how and where tinnitus is generated within the brain and the possible basis for novel treatments��

What is somatotosensory tinnitus?
Hearing researchers in the US and Europe have been investigating the fascinating phenomenon known as somatosensory tinnitus. This is a particular type of tinnitus in which the tinnitus patient is able to change the loudness or tone of their tinnitus by facial movements such as jaw clenching or jaw opening or tensing their neck muscles. Other patients report that other muscular movements or even moving their eyes in a specific direction can affect their tinnitus.�

It is referred to as somatosensory because it involves the activity of sensory nerves that originate from the rest of the body. These nerves convey information to the brain about what is going on in the rest of the body and its immediate environment. This information for example is essential in telling the brain, from second to second, where our arms and legs are how much tension there is in our muscles. This somatosensory system is distinct from the special senses of our ears and eyes, but the brain also has to bring all the information together from the senses to make proper sense of what the whole body is doing.

Tinnitus patients have reported these effects for some years.�� Over the last decade or so somatosensory tinnitus began to attract the attention of hearing researchers because the reports of it were consistent and occurred in a considerable number of patients.� It also attracted their attention because it provided a way of finding out more about how tinnitus might be generated in the brain. This in turn could provide new inroads into therapy for some tinnitus patients.

New findings about what parts of the brain appear to be involved in somatotosensory tinnitus
One group at the forefront of research in this area is directed by Professor Susan Shore at the Kresge Hearing Research Institute in the University of Michigan.� By studying the complex circuitry of the brain, Professor Shore and her team have discovered that the major nerve supplying the face known as the trigeminal nerve can play a major role in affecting the perception of tinnitus.

It seems that the part of the brain dealing with the trigeminal nerve has strong connections with parts of the brain that receive input from the ear. They showed that patterns of nerve activity in the early stage of the auditory system in the brain are affected by the trigeminal nerve. There is also evidence that noise damage has led to an increased compensatory influence of the trigeminal system on auditory parts of the brain.

Somatotosensory tinnitus could lead to new therapies for tinnitus patients
Some early studies carried out by Professor Robert Levine in the US and Dr Tanit Sanchez in Spain provides some evidence tinnitus can be improved in some patients. The treatment includes exercises or manipulations of the parts that were known to control their tinnitus. These preliminary findings, once researched in more depth, may provide a novel way of treating specific groups of tinnitus patients.

This work was reported at the Tinnitus Research Initiative meeting held in Monaco in July this year