Headphones that switch sounds from one ear to the other could be a radical new treatment for tinnitus – the ringing in the ears that affects around five million people in Britain.
When a sound comes from the wearer’s right side, it is picked up by a microphone in the headphones and redirected to the left ear. The opposite happens with sounds coming from the left.
Scientists think that mixing up the direction of sound, where the eyes tell the brain it’s coming from one place but the ears tell the opposite, helps to ‘rewire’ the auditory nerve (which connects the ear to the brain). ‘. And this ‘reduces’ the tinnitus.
The idea for a headphone 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 that 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 from temporary tinnitus, but in about one in a hundred people the tinnitus is long-lasting and is often accompanied by hearing loss.
When the ears are exposed to loud noise or infections, tiny hair cells that transmit sounds to the brain become stressed and release excess amounts of a chemical called glutamate. This “glutamate storm” overstimulates (and ultimately kills) the nerve cells in the inner ear, which send sound impulses to the auditory cortex, the part of the brain that processes sound.
This activates cells in the auditory cortex so that they continuously transmit sound to the brain, causing people to ‘hear’ ringtones, for example. In some, the cells remain in this ‘switched on’ state.
At this point it is more difficult to treat. There are no medications for it, and treatments include talk therapy, which helps patients live with the condition, or sound therapy, which uses background noise to distract them.
The idea for headphone treatment came from mirror therapy, which is used for phantom limb pain, where amputees still feel pain from the removed limb. By ‘hiding’ the affected limb behind a mirror that reflects the healthy limb, and focusing on this reflection, the brain is ‘tricked’ into thinking that 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 US, who developed the prototype headphones, think they work in a similar way: they ‘rewire’ connections between nerve cells so that they no longer register tinnitus as a real external sound.
Results published in the Journal of the American Academy of Audiology in 2022 showed that 18 volunteers experienced significant improvements in their symptoms. Now a trial is underway with 50 patients who will wear the headphones for three hours a day for three weeks, or a regular pair that plays sound in the ear closest to the sound source. The results are expected later this year.
Commenting on the treatment, Dr Will Sedley, lecturer in neurology at Newcastle University, said: ‘It’s a nice idea, but we need the results of the research before we can say it works. The only thing we know that works well for many people is talk therapy.’