14 DAY TRIAL // University of Pittsburgh School of Medicine investigators have finally cracked the mystery surrounding how the relentless ringing in the ears known as tinnitus develops. The condition is oftentimes life-changing, and discovering its root cause was one of the last remaining obstacles to developing a cure.
Tinnitus is triggered by prolonged exposure to loud music, such as for example during a really loud concert, or by being subjected to hearing explosions and gunshots from very nearby. The condition affects soldiers returning home from theaters of operations around the world.
Millions of other people suffer from the disorder without being exposed to these triggering factors. Now, researchers believe they know why the human brain triggers tinnitus in certain individuals.
The brain's auditory center – the area that deals with receiving and processing audio signals from the ears – is made up of several key neural pathways. Some of these pathways are really under-inhibited in people with tinnitus, and therefore never stop transmitting signals to the auditory cortex.
Details of the new research will appear in this week's early online issue of the esteemed journal Proceedings of the National Academy of Sciences (PNAS). The discovery was made possible by the use of a new imaging technique that was able to reveal the auditory circuits.
This finding is made all the more important by the fact that there is currently no cure for tinnitus. Now that scientists know about the neural pathways, they can start developing drugs that target these nerve cells directly.
Boosting the brain's natural ability to inhibit these circuits could lead to the elimination of the tinnitus sensation from the ears. This could be the best way to investigate in finding a cure at this point.
“This auditory imbalance leaves the patient hearing a constant ringing, buzzing or other irritating noise even when there is no actual sound,” explains Pitt School of Medicine assistant professor of otolaryngology and neurobiology Thanos Tzounopoulos, PhD.
“Tinnitus drowns out music, television, co-workers, friends and family, and it profoundly changes how the patient perceives and interacts with the world,” adds the expert, who was the senior investigator on the new work.
One of the directions of research the expert and his team will now take is to investigate how to use the inhibitory neurotransmitter GABA to their advantage. Tzounopoulos believes that increasing GABA-mediated inhibition in the auditory cortex circuits could reduce tinnitus to manageable levels.