(Montreal) Scientists today have a better understanding of tinnitus and increasingly effective treatment options are available, said a specialist from Harvard University during a long conversation with The Canadian Press.
Tinnitus is those persistent sounds ― whistling, buzzing, rumbling, even music ― that only the person suffering from it hears.
While the problem may seem trivial, in reality it could affect patients’ quality of life so much – for example, by preventing some from sleeping – that anxiety and depression could result.
Tinnitus is estimated to affect between 10% and 15% of the population, which represents millions of people.
The ear is a wonderful device. It is a device that is able to inform you about sounds that are very, very, quiet, like a whisper, and sounds that are very, very, loud, like an explosion. And if you think about what the ear can do, it’s something that is unparalleled. There is nothing on Earth that is capable of doing something like this.
Stéphane Maison, professor at Harvard University
Experts have long believed that tinnitus is the brain’s response to hearing loss, Mr. Maison said, a phenomenon that could be compared to the “feeling” that persists after a limb is amputated.
“The brain will receive information from all your sensory systems, the visual system, the olfactory system, the auditory system, perception too,” he explained. And when the brain no longer receives this information, it will try to compensate for this loss. And one of the ways to compensate for this loss is to increase the gain, to increase your activity. Basically, he will become hyperactive to try to compensate. »
It was a discovery made in 2009 by American researchers Sharon Kijawa and Charlie Liberman that turned our understanding of tinnitus upside down, he added.
In experiments on mice, Mme Kijawa and Mr. Liberman found that when hearing loss begins to set in, the first fibers to disappear are those that make it possible to hear loud sounds. This explains why some people have difficulty following a conversation in a noisy environment, such as in a restaurant: the fibers responsible for understanding high-intensity sounds no longer work, and those responsible for understanding low-intensity sounds are completely saturated.
This also explained why people who said they suffered from tinnitus could obtain a normal result on an audiogram, since the normal hearing test is not designed to detect the loss of the fibers responsible for understanding loud sounds.
“It is therefore very possible that people who have normal hearing have tinnitus, that they have a hearing loss that is not documented on the audiogram,” said Mr. Maison, who emphasizes that this reinforces the brain hypothesis that compensates for hearing loss.
Auditory fibers degenerate with age and following prolonged or repeated exposure to noise. However, experiments carried out on mice have demonstrated that it may be possible to “reconnect” these fibers by administering neurotrophins, proteins important in the survival, development and functioning of neurons.
Indeed, Mr. Maison said, the fibers that stopped functioning are not entirely dead: rather, it is the “connection” with the brain that has been lost.
“So we could try to reconnect these fibers and restore the information,” he said. If it works, and that’s a big IF, we could […] maybe bring information back to the brain, and maybe the brain will say, “I don’t need to be hyperactive because now I’m getting this information that was missing,” and maybe the brain will decrease the gain. »
This intervention should probably be accompanied by some “reconditioning” of the brain to help reduce this gain, Mr. Maison said.
Mixed results
There are currently very few treatment options available to help patients suffering from tinnitus, and the results are often mixed: while some patients say it helps, others say the problem remains very serious. too present.
The thing that’s probably the least controversial about tinnitus, Mr. Maison said, is its association with stress.
“So anything we can do to reduce stress can have a positive impact on tinnitus,” he said.
Stress could even be generated by the sudden appearance of these noises in the ear, recalled Mr. Maison. Not knowing what is happening to them, the patient may think that they have cancer, or that they are going crazy, which will increase their stress level and potentially make the problem worse. Understanding what is happening better may therefore provide some relief.
Hearing aids may also be useful, although it is important to be “honest with the patient by telling them that it will not be perfect, that they will not hear like they did when they were 15,” Mr. Home. Other hearing aids continuously produce “white noise” which may mask tinnitus symptoms.
The third option is the use of cognitive behavioral therapy, to learn to better accept and have a less emotional reaction to tinnitus, added Mr. Maison.
We finally find certain devices on the market that try to act at the level of the central nervous system to, essentially, “recondition” the brain and reduce “sometimes significantly” the perception of tinnitus, said Mr. Maison.
“To date, there is no cure, but we are working on it,” he concluded.