Tinnitus is the sensation of hearing ringing or buzzing in the ears. It is often the result of an underlying condition or a medication’s side effect. It can also be caused by age-related hearing loss, ear injury, or a circulatory problem. While ringing in the ears is not harmful, it can be a very irritating symptom.
Tinnitus has also been quite difficult to remedy, with the condition not being fully understood and having no definitive treatment.
Looking beyond the ears
New research from the University of Illinois aims to change our scientific understanding of tinnitus. They have discovered that the condition is associated with changes in the brain, not just in structures within the ear. They believe that tinnitus causes the brain to stay more at attentive and less at rest.
“Tinnitus is invisible. It cannot be measured by any device we have, the way we can measure diabetes or hypertension. So you can have this constant sound in your head, but nobody else can hear it and they may not believe you. They may think it’s all in your imagination. Medically, we can only manage some symptoms, not cure it, because we don’t understand what’s causing it,” said study leader Fatima Husain, a professor of speech and hearing science at the University of Illinois.
Not having the tools to definitively diagnosis tinnitus has made treating the condition a challenge. Tinnitus may present differently from patient to patient and potentially have entirely different causes and severity, leading to inconsistent study results.
Creating a baseline for all tinnitus sufferers
The results of this study not only help to diagnose the condition, but also allows it to be treated in a more streamlined fashion.
Through the use of an MRI, the researchers were able to isolate a region of the brain, called the precuneus, that seems to be directly involved in the development of tinnitus symptoms.
This structure of the brain is connected to two inversely related brain networks—the dorsal attention network and the default mode network. The former is responsible for holding a person’s attention when needed, and the latter handles “background” functions of the brain when a person is at rest.
Brain regions seem to play a role
These two regions were seen to work in tandem. When one is on, the other is off. Those suffering from tinnitus seem to have an abnormality in these brain regions. Chronic sufferers were found to have more connections to the dorsal attention network and less to the default mode network. The severity of tinnitus symptoms was related to an increase in the overall effect of the neural networks.
“For patients, this is validating. Here is something related to tinnitus which is objective and invariant. It also implies that tinnitus patients are not truly at rest, even when resting. This could explain why many report being tired more often. Additionally, their attention may be engaged more with their tinnitus than necessary, and that may lessen their attention to other things. If you have bothersome tinnitus, this may be why you have concentration issues,” Husain said.
However, the researchers mention that those with recent-onset tinnitus did not show differences in precuneus connectivity. It is not known if they will develop these neural connections later on.
While more research is needed to find the precise origins of tinnitus, the researchers hope their findings will contribute to future studies and treatments plans for tinnitus.