Can Tinnitus Be Cured? Here’s What the Latest Research Says
Until recently, most tinnitus patients had little reason to believe doctors would ever be able to completely cure or reverse the affliction.
Until recently, most tinnitus patients had little reason to believe doctors would ever be able to completely cure or reverse the affliction. Drug therapies had consistently failed, and so had more invasive procedures — including some surgeries to remove the auditory nerve that transmits sound from the ear to the brain, according to past research. (1,2)
One of the big problems associated with curing tinnitus, experts say, is that it’s really a symptom of multiple conditions, as opposed to being a single condition with a predictable trigger. In fact, more than 200 different conditions — problems ranging from hearing loss to head or neck trauma — have been linked with tinnitus, which makes it a real bear to try to stop. (3)
Michael Kilgard, PhD, a professor of neuroscience at the University of Texas in Dallas, says tinnitus is like pain in that it is a symptom that can result from many different causes. And like pain, he says, “after starting someplace else it often ends up in the brain.”
What does he mean by “ends up in the brain”? Essentially, something that causes even temporary hearing damage — such as exposure to very loud noise or a blow to the head — can change activity patterns in the brain in ways that cause the ringing. Even though some damage or problem in the ear triggered tinnitus to begin with, you continue to hear the sound you do because of a signal from the brain.
It’s the same mechanism that’s happening in people who feel a phantom limb sensation after losing a limb, explains Susan Shore, PhD, a professor of otolaryngology, molecular physiology, and biomedical engineering at the University of Michigan in Ann Arbor. With tinnitus the loss of hearing causes specific brain neurons to increase their activity as a way of compensating, she explains. “These neurons also synchronize their activity as they would if there were a sound there, but there is no external sound,” she adds.
Unfortunately that means tinnitus is a very complicated condition that involves several systems of the body. The good news, though, is that as doctors and researchers have developed a better understanding of the mechanisms behind tinnitus, they’ve also been able to develop new and promising treatments that target the brain rather than the ear — and have more of a chance of actually reversing the problem.
Here are a few areas of research that are giving tinnitus researchers hope that a cure is possible.
Vagus Nerve Stimulation Resets the Patterns of Brain Activity That Have Gone Awry in Tinnitus
In many cases, tinnitus is caused by hyperactivity (or too much activity) in the brain’s auditory cortex. “When there’s damage or a loss of input in the ear [such as hearing loss, head trauma, or a blood vessel problem], the brain tries to turn up certain channels in order to compensate,” Dr. Kilgard explains. When the brain doesn’t get that tuning quite right, the result is tinnitus.
But one of the awesome powers of the human brain is its adaptability. “It can learn and reorganize itself every time you practice something new,” Kilgard says. His research, including a study published in February 2014 in the journal Neuromodulation, has shown this adaptability may be key to helping the brain “turn down” the hyperactivity that can lead to tinnitus, he says. (4)
To keep the brain activated and aware, Kilgard’s therapy involves stimulating the vagus nerve, which is actually a pair of nerves that runs inside the neck and into the brain. “All the stuff you brains learns about your body — it all comes in through the vagus nerve,” he says. “We trick the brain into thinking it’s learning something important by stimulating this nerve in the neck.”
The treatment involves implanting a small electrode into a person’s neck near the vagus nerve. The patient then listens to specific tones that are paired with small electric pulses sent to the vagus nerve. This vagus nerve stimulation, coupled with the sound-based stimulation of the auditory cortex, can “turn down” the patient’s tinnitus. Though, Kilgard adds, “It’s not 100 percent yet.”
The difficult part is getting the brain to pay attention during this practice. “Normally, when you keep sending the brain a signal, it ignores it,” he says. An example of this is the feeling of clothing touching skin. The brain quickly learns to ignore these sensations, because they would otherwise drive a person to distraction.
“So far, half of patients get about half better.” Also, the treatment involves multiple sessions spread out over months, not just a single round of therapy.
But it’s still a significant improvement. And Kilgard says he and others are working to make the treatment even more effective. He suspects this type of therapy is not too far off from being available to patients outside of research studies. “It’s in the late stages of development,” he says. “It could be available to the public in as little as a year or two.”
Auditory-Somatosensory Stimulation Focuses on Rewiring Touch-Sensitive Nerves
Auditory-somatosensory stimulation is a similar treatment approach to Kilgard’s, in that its goal is to retune the faulty patterns of brain activity that can cause tinnitus. It involves pairing sounds played in the ear with specially timed electric impulses, which are administered to touch-sensitive nerves using a pad attached to the neck, Dr. Shore explains about the research she’s working on.
Shore says her therapy isn’t for everyone — at least not yet. So far, she’s only treated patients who have a specific form of tinnitus that changes in intensity or pitch when a person moves certain parts of her body. For example, some tinnitus sufferers find the sound in their ears lessens when they clench their teeth or open their mouths wide. This suggests that some touch inputs can influence the tinnitus, Shore says. (Roughly two-thirds of tinnitus patients have this form of the condition, she adds.)
Her most recent study, published in January 2018 in the journal Science Translational Medicine, showed success rates similar to Kilgard’s on 20 adult tinnitus patients. (5) People who underwent the therapy 30 minutes a day for one month reported about a 50 percent drop in the loudness of their tinnitus. More than half of the study participants also reported that their tinnitus bothered them less after the therapy, she says.
Other Promising Therapies in the Works
Like Shore and Kilgard’s work, most of the promising research on tinnitus has to do with stimulating or altering the brain’s hyperactivity in ways that reduce tinnitus. Some studies have shown electromagnetic brain stimulation — using either invasive or noninvasive techniques, including procedures that involve surgically implanted electrodes or scalp electrodes — may help reverse a patient’s tinnitus. (6) While none of these treatment options are currently available, all have shown some success in treating the condition.
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References
- Soleymani T, Pieton D, Pezeshkian P, et al. Surgical Approaches to Tinnitus Treatment: A Review and Novel Approaches. Surgical Neurology International. October 29, 2011.
- House JW, Brackmann DE. Tinnitus: Surgical Treatment. Ciba Foundation Symposium. 1981.
- Tinnitus Causes. American Tinnitus Association.
- De Ridder D, Vanneste S, Engineer ND, et al. Safety and Efficacy of Vagus Nerve Stimulation Paired With Tones for the Treatment of Tinnitus: A Case Series. Neuromodulation. February, 2014.
- Marks K, Martel DT, Wu C, et al. Auditory-Somatosensory Bimodal Stimulation Desynchronizes Brain Circuitry to Reduce Tinnitus in Guinea Pigs and Humans. Science Translational Medicine. January 3, 2018.
- Tinnitus Experimental Therapies. American Tinnitus Association.