- Published on 20 January 2014
University of Michigan Medical School (U-M) researchers have reported new scientific findings that help to better explain the mechanisms underlying the constant ringing, buzzing, hissing, humming or other noises so well known to people with tinnitus.
The results of the team’s research were published in the Journal of Neuroscience in December last year. The authors report that the precise timing of auditory signals in relation to one another prompts changes in the nervous system’s plasticity mechanisms. They exposed guinea pigs to narrowband noise producing a temporary elevation of auditory brainstem response thresholds. 60% of the test animals developed tinnitus, and after noise exposure and tinnitus induction, a process known as stimulus timing-dependent multisensory plasticity was measured. It was found that this timing process is altered in animals with the condition, suggesting a causative role. “It’s as if the signals are compensating for the lost auditory input, but they overcompensate and end up making everything noisy,” says Susan Shore, senior author on the paper.
Another important finding was that not all exposed animals developed the condition, like in humans exposed to noise. Animals that did not get tinnitus showed fewer changes in their multisensory plasticity than those with evidence of the condition.
Although the studies were in animal models, the discovery opens up new avenues for treating tinnitus by identifying a novel target. The U-M team has a patent pending and has started to develop a device based on the approach, targeting the neural activity in the auditory pathway.Source: Ann Arbor Journal