Headphones that swap sounds from one ear to the other could be a radical new treatment for tinnitus — the ringing noise in the ears that affects around five million people in the UK.
When a noise comes from the wearer’s right-hand side, it is picked up by a microphone in the headphones and re-routed to the left ear. The opposite happens with sounds emanating from the left.
Scientists think jumbling the direction of sound, with the eyes telling the brain it’s coming from one place but the ears telling it the opposite, helps to ‘rewire’ the auditory nerve (which connects the ear to the brain). And this ‘turns down’ the tinnitus.
The idea for headphones treatment came from mirror therapy, which is used for phantom limb pain (Stock Image)
Results published in the Journal of the American Academy of Audiology in 2022 showed 18 volunteers experienced significant improvements in their symptoms (stock photo)
The results of a small trial suggest that using the headsets for two hours a day for three weeks significantly reduces tinnitus. Many people suffer temporary tinnitus, but for around one in 100, the ringing is long term and is often combined with hearing loss.
When the ears are exposed to loud noise or infections, tiny hair cells that transmit sounds to the brain become stressed and emit excess quantities of a chemical called glutamate. This ‘glutamate storm’ over-stimulates — and eventually kills — nerve cells in the inner ear, which send sound impulses to the auditory cortex, the part of the brain that processes noise.
T his leaves cells in the auditory cortex switched on so they constantly relay sound to the brain, causing people to ‘hear’ ringing, for instance. In some, the cells remain in this ‘switched on’ state.
By this point, it is more difficult to treat. There are no drugs for it, and treatments include talking therapy, which helps patients live with the condition, or sound therapy, where background noise is used to distract them.
The idea for headphones treatment came from mirror therapy, which is used for phantom limb pain — where amputees still feel pain from the removed limb. By ‘hiding’ their affected limb behind a mirror which reflects the healthy limb, and focusing on this reflection, the brain is ‘tricked’ into thinking both limbs are intact. Studies suggest this leads to rewiring in the brain that reduces the perception of pain.
Scientists at Spaulding Rehabilitation Hospital in Massachusetts in the U.S., who developed the prototype headphones, think they work in a similar way, ‘rewiring’ connections between nerve cells so they no longer register tinnitus as a real external sound.
Results published in the Journal of the American Academy of Audiology in 2022 showed 18 volunteers experienced significant improvements in their symptoms. Now a trial is under way with 50 patients who will wear the headphones for three hours a day for three weeks, or a regular pair that play noise into the ear closest to the noise source. The results are expected later this year.
Commenting on the treatment, Dr Will Sedley, a lecturer in neurology at Newcastle University, said: ‘It’s a neat idea, but we need the results of the trial before we can say it works. In the meantime, the one thing we know does work well for many people is talking therapy.’
