Reprogramming Brain Circuits to Alleviate the Symptoms of Tinnitus
An innovative treatment for a common hearing disorder…
For the nearly 50 million Americans who suffer from the hearing condition tinnitus, every moment of every day is filled with unwanted noise. Whether it manifests as ringing, hissing, humming or buzzing, that non-stop sound can be disruptive and even debilitating.
U-M Professor Susan Shore first became interested in tinnitus while studying brain function in the dorsal cochlear nucleus, the first station for signals arriving from the auditory nerve. Early on, she discovered that other sensory information from the body’s “touch system” — the somatosensory system — was also integrated in the cochlear nucleus. This helped explain why people with tinnitus could often alleviate symptoms by pressing on their face, moving their jaw or clenching their teeth.
Follow-up studies showed that, after hearing loss, there was upregulation of somatosensory projections to the auditory system, leading to increased firing of these neurons, or hyperactivity, which is a hallmark of the brains of tinnitus sufferers. Further, by stimulating the sensory connections, Shore and her team were able to modify the firing rate of the neurons, a rate that increases in tinnitus sufferers. This technique resulted in long-lasting effects — a process known as long-term neuroplasticity.
Shore harnessed these findings to build a device, presently being assessed in a proof-of-concept trial, to make the neuron firing rate decrease at the particular tinnitus frequency, thereby relieving symptoms.
While a commercially available treatment is likely still some time away, the initial findings have been promising, and Shore has been working with U-M Innovation Partnerships to assess the feasibility of a system that could be distributed through existing audiological channels.
“There may never be a cure for tinnitus, and we have no universally effective treatment to offer right now,” says Shore. “Our hope is that we may have found a way to alleviate the symptoms of tinnitus, which could be hugely beneficial for millions of people.”
[source: U-M Innovation Partnerships 2014 Impact Report]