For tens of millions of Americans, there’s no such thing as the sound of silence. Instead, even in a quiet room, they hear a constant ringing, buzzing, hissing, humming or other noise in their ears that isn’t real. Called tinnitus, it can be debilitating and life-altering.
Tens of millions of Americans “hear” ringing, buzzing or humming in their ears — an annoying and sometimes disabling condition known as tinnitus.
Now, University of Michigan Medical School researchers report new scientific findings that help explain what is going on inside these unquiet brains.
The discovery reveals an important new target for treating the condition. Already, the U-M team has a patent pending and device in development based on the approach.
The critical findings are published online in the prestigious Journal of Neuroscience. Though the work was done in animals, it provides a science-based, novel approach to treating tinnitus in humans.
Susan Shore, the senior author of the paper, explains that her team has confirmed that a process called stimulus-timing dependent multisensory plasticity is altered in animals with tinnitus – and that this plasticity is “exquisitely sensitive” to the timing of signals coming in to a key area of the brain.
That area, called the dorsal cochlear nucleus, is the first station for signals arriving in the brain from the ear via the auditory nerve. But it’s also a center where “multitasking” neurons integrate other sensory signals, such as touch, together with the hearing information.
Shore, who leads a lab in U-M’s Kresge Hearing Research Institute, is a professor of Otolaryngology and Molecular and Integrative Physiology at the U-M Medical School, and also professor of Biomedical Engineering, which spans the Medical School and College of Engineering.
She explains that in tinnitus, some of the input to the brain from the ear’s cochlea is reduced, while signals from the somatosensory nerves of the face and neck, related to touch, are excessively amplified.