GOT that ringing in your ears? Tinnitus, the debilitating condition that plagued Beethoven and Darwin, affects roughly 10 per cent of the world’s population, including 30 million people in the US alone. Now, a device based on vagus nerve stimulation promises to eliminate the sounds for good by retraining the brain.
At the moment, many chronic sufferers turn to state of the art hearing aids configured to play specific tones meant to cancel out the tinnitus. But these do not always work because they just mask the noise.
The new device, developed by MicroTransponder in Dallas, Texas, works in an entirely different way. The Serenity System uses a transmitter connected to the vagus nerve in the neck – the vagus nerve connects the brain to many of the body’s organs.
The thinking goes that most cases of chronic tinnitus result from changes in the signals sent from the ear to neurons in the brain’s auditory cortex. This device is meant to retrain those neurons to forget the annoying noise.
To use the system, a person wears headphones and listens to computer-generated sounds. First, they listen to tones that trigger the tinnitus before being played different frequencies close to the problematic one.
Meanwhile, the implant stimulates the vagus nerve with small pulses. The pulses trigger the release of chemicals that increase the brain’s ability to reconfigure itself. The process has already worked in rats (Nature, doi.org/b63kt9) and in a small human trial this year, where it helped around half of the participants.
“Vagus nerve stimulation takes advantage of the brain’s neuroplasticity – the ability to reconfigure itself,” says Michael Kilgard at the University of Texas at Dallas, and a consultant to MicroTransponder.
Four clinical trials of the system, funded by the National Institutes of Health, are taking place at US universities, and Kilgard thinks a consumer version could be approved by mid-2015.
Fatima Husain at the University of Illinois at Urbana-Champaign cautions that because the implant is an invasive procedure it will only be a good idea for people whose lives are extremely affected by the condition. But if the mechanism that generates tinnitus can be reset, it could work, she says.