New Developments in Tinnitus Research

Every day breakthrough medical treatments come to market, making life easier for patients with common health conditions. New drugs like HARVONIⓇ are curing people with Hepatitis C, an infection that once killed more Americans than any other infectious disease. Biologics offer new hope for patients with cancer, rheumatoid arthritis and diabetes. Wearable medical devices are being used to monitor cardiac patients for heart arrhythmias. Ketamine is being hailed as a potential new fast-acting treatment for people suffering from depression.

But What About Tinnitus Treatment Options?

Despite the fact that tinnitus is one of the world’s most common medical conditions, researchers are only just beginning to understand it. Tinnitus sufferers continue to wait anxiously for new advancements. Fortunately, there are several promising tinnitus research initiatives that are being pursued, three of which we will discuss below.

First, What Is Tinnitus?

Tinnitus is sound you hear that does not have an external source. Most people with tinnitus describe it as ringing in the ears, but patients can experience tinnitus sounds in many different ways, including whistling, buzzing, chirping, hissing, humming, roaring or even a heartbeat. It can be loud or soft, occasional or constant, a mild annoyance or an incapacitating chronic condition. Currently, no cure for tinnitus exists.

1. Medications to repair inner ear damage: inside the inner ear is a very small spiral tube called the cochlea. The cochlea contains the nerve endings that transmit sound vibrations from the middle ear to the auditory nerve. Noise-induced damage to the 15,000 tiny hair cells and neurons in the cochlea or to the auditory nerve is the leading cause of hearing loss and tinnitus, many researchers believe. And while there are existing drugs for effectively treating middle ear infections, nothing so far works on the cochlea. But researchers, drug companies and investors are partnering to change that. In November 2017, Decibel Therapeutics of Boston entered into a partnership with Regeneron, a biotech drug developer in Tarrytown, New York to develop tinnitus relief therapies that target the cochlea. And in Woburn, Massachusetts, Frequency Therapeutics is focusing on developing small molecule drugs that activate dormant progenitor cells, or types of stem cells, to repair damaged cochlear hair cells. This could potentially restore both age-related and noise-induced hearing loss in patients and in theory, improve or treat tinnitus symptoms. In December, Frequency announced the successful completion of a Phase 1 human study of FX-322, a progenitor cell activation drug, demonstrating its safety and tolerability. The team at Frequency expects to start a Phase 2 clinical study in the second half of 2018.
2. Vagus Nerve Stimulation: researchers are looking at Vagus Nerve Stimulation or VNS, as a solution to lessen patients’ tinnitus symptoms. MircoTransponder, Inc. has developed what they call the Serenity System. The Serenity System pairs VNS with sound therapy. The VNS causes the release of neurochemicals in the brain, helping reduce symptoms by interrupting misfiring auditory nerves and decreasing brain hyperactivity over time. The Serenity System device is about half the size of a matchbox and is implanted under the skin and attached to the vagus nerve. After the device is properly calibrated, the patient can do their own tinnitus therapy at home. To begin, the patient puts on headphones and presses a computer key. Each time a sound is played, the wireless transmitter sends a signal to the device, which then properly stimulates the vagus nerve. While more clinical trials are needed for the device, early tinnitus treatment results are promising. One study showed that 56% of tinnitus sufferers experienced a clinically significant improvement.
3. Other experimental devices: a team of researchers from the University of Michigan and McMaster University in Ontario, Canada, have developed an experimental device that delivers 30 minutes of sensory stimulation. The device alternates between brief audio tones delivered via headphones and light pulses delivered to the patient’s neck or cheek. The researchers hypothesize that tinnitus originates in a part of the brain called the dorsal cochlear nucleus. They believe that the dorsal cochlear nucleus’ neuron networks sometimes fire simultaneously even when they’re not supposed to. The new device disrupts that synchronized firing, interrupting the conditions that lead to tinnitus. The researchers tested the device on 20 subjects (after first achieving successful results on guinea pigs) who used the device at home for half an hour each day for one month. At the end of the study, two participants reported being completely cured of their tinnitus symptoms, while 11 others reported a reduction in volume or pitch. Notably, neither human nor guinea pig reported any results with only audio or face and neck pulses stimulation. Alternating between the sound and the light appeared to be the key to the device’s apparent success.