Tinnitus research could help millions

Have you ever felt that unsettling sensation of ringing in your ears? What about a chirping, buzzing, whistling or hissing sound that isn’t really there? It’s called tinnitus.

The majority of Australians will experience temporary tinnitus at some point in their life, usually after exposure to loud noises. When it sticks around for months, or even years, it can cause sleepless nights, concentration problems, depression, and anxiety.

What causes tinnitus?
Our ears are made up of three parts: the outer ear, middle ear, and inner ear.

The inner ear is the crucial part to be aware of when talking about tinnitus. The cochlea is a part of the inner ear. It is a small curled tube filled with fluid and lined with tiny hair cells.

Under normal circumstances, we hear when these tiny hair cells receive information from small bundles of fibres called stereocilia, which respond to vibrations from sound waves entering the ear.

The hair cells then translate vibrations into electrical impulses that are carried to the brain by sensory nerves. The nerves send unique signals for each sound – high-frequency and low-frequency sounds affect the hair cells in different ways. This is how sounds are distinguished from one another.

In tinnitus sufferers, there is some breakdown in this process that results in the perception of sound when there is no external noise actually present.

There isn’t one scientific answer as to why.

One hypothesis is that the hair cells are damaged and continuously switched to the ‘on’ position, so the brain thinks it is receiving sounds that it is not. Another is that the noise filtering system in the brain isn’t working. This system stops you from hearing noises that are made by your central nervous system functioning, so the pulsing in your ears may be the sounds of your neurons firing.

While the specific mechanism causing tinnitus is unclear, researchers have established that it has a high correlation with hearing loss. As hearing loss is often a gradual process, it can go undetected, and people are often surprised to learn that it can be the cause of their tinnitus.

The frequency of a person’s tinnitus tends to be of, or around, the same frequency where there is the most hearing loss. So high pitch tinnitus is likely to represent hearing loss of higher frequency sounds.

Even though hearing loss is a frequent factor, some people with full hearing may also experience tinnitus.

Types of tinnitus
Subjective – this is the most common type, and it is classed as a sound that only the sufferer can hear.

Objective – this is quite rare as the sound can also be heard by someone else (usually a doctor) and tends to be a sign that something is wrong with the vascular system.

Treatments for tinnitus
A cure for tinnitus is something that has eluded researchers. But now, in the largest clinical study of its kind, research has shown that combining sound and electrical stimulation of the tongue can significantly reduce the effects of this frustrating condition. The therapeutic effects can be sustained for up to 12 months post-treatment.

The study was conducted by researchers from the University of Minnesota, Trinity College, St James’s Hospital, University of Regensburg, University of Nottingham, and Irish medical device company Neuromod Devices Limited.

Tinnitus affects around 10 to 15 per cent of the world’s population, so these findings could potentially help millions.

The research was published as the cover story of Science Translational Medicine, an interdisciplinary medical journal by the American Association for the Advancement of Science (AAAS).

University of Minnesota Associate Professor Hubert Lim in the Department of Biomedical Engineering (College of Science and Engineering) and the Department of Otolaryngology (Medical School) was the senior author of the study sponsored by Neuromod Devices.

The study represents the largest and longest followed-up clinical trial ever conducted in the tinnitus field. Out of the 326 enrolled participants, 86 per cent of them reported a decrease in tinnitus severity after 12 weeks of treatment. Many of them went on to experience the improvement 12 months post-treatment.

“I am truly proud of our company’s ability to perform such a large-scale randomised clinical trial in two countries,” Prof. Lim said. “This study tracked the post-treatment therapeutic effects for 12 months, which is a first for the tinnitus field in evaluating the long-term outcomes of a medical device approach. The outcomes are very exciting and I look forward to continuing our work to develop a bimodal neuromodulation treatment to help as many tinnitus sufferers as possible.”

How does it work?
The device used in the study, now branded as Lenire, was developed by Neuromod Devices and consists of wireless headphones that deliver sequences of audio tones layered with wideband noise to both ears, combined with electrical stimulation pulses delivered to 32 electrodes on the tip of the tongue.

Lenire is a non-invasive medical device that can be used at home. It has been designed to be used for the treatment of tinnitus under the supervision of an appropriately qualified healthcare professional.

If Lenire is found to be right for you, your clinician will put together a treatment plan that will typically include daily 30-minute sessions and at least two follow up visits over three months.

Clinic locations
Currently, the only Lenire clinics are in Ireland, Germany and Belgium but Neuromod is looking at expanding their reach as soon as possible

During the sessions:

  1. Customised sounds are played through bluetooth headphones to activate the nerve involved in hearing (the auditory nerve).
  2. Mild and safe energy pulses are delivered to the surface of the tip of the tongue to activate touch nerves (mainly the trigeminal nerve).
  3. The activated nerves convert the sound and the energy pulses into signals that are relayed to the brain, where over time the unique signal patterns work to reduce and soothe the perceived tinnitus experience.

Lenire comes with a handheld remote that controls the timing, intensity and delivery of the stimuli. The device is configured to each individual before the first treatment and can be tweaked by the healthcare professional to achieve maximum benefits.

A participant in the study has claimed the sessions are ‘very pleasant and relaxing’ and ‘my mood and my perspective on [tinnitus] hugely improved’.

Do you suffer from tinnitus? Have you tried any treatments?

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Written by Ellie Baxter

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