Study Finds Cause for Tinnitus

University of Pittsburgh School of Medicine researchers have found tinnitus is caused by an under-inhibition of neural pathways. Tinnitus is a condition that leads patients to hear constant ringing, buzzing or other noises. There are currently 50 million people living with tinnitus; 16 million have severe enough symptoms to need medical attention, and 2 million who cannot carry out daily activities.
Tinnitus is gaining greater attention because it is the most common service-connected disability among veterans of the Iraq and Afghanistan wars according to the American Tinnitus Association

Kenneth Nye of Jeannette, Pennsylvania, who has been living with the condition for 10 years, says that tinnitus has been a challenge. "I have buzzing, ringing, beeping, chirping, hissing, whistling sounds occurring in my ears; either alone or in some combination 24 hours a day. And there's no reason for those sounds to be there."

Nye says that once the noises began he became depressed, suffered panic attacks, found it hard to concentrate, and could not sleep. He says that what helped him was the UPMC Tinnitus Control Program. There they gave him with counseling and a treatment called Auditory Habituation, where a patient is given sound in a hearing aid sized device to compete with the tinnitus sound they are already hearing. After two years of treatment Nye says that he has learned to keep the tinnitus in check.

Dr. Thanos Tzounopoulos, assistant professor of otolaryngology and neurobiology at Pitt, led the study. He says that auditory circuits are more excitable in tinnitus sufferers but it has never been clear why until now, hence no common, effective treatment has been available to patients. "The main reason is that it's not very clear yet what is it that leads to this phantom sound, what is the cause. And, you know, when you do not know the cause it's kind of hard to design effective treatment."

To identify what goes wrong with the circuits researchers created tinnitus in mice by sedating them and then exposing one ear to 45 minutes of 116 decibel sound, approximately the amount in an ambulance siren. The team, weeks later, then confirmed the mice had tinnitus.

Dr. Tzounopoulos says that the mice that had tinnitus had decreased inhibition. He says that the brain emits excitable and inhabitable forces. Neurotransmitters excite while neurochemicals inhibit. The brain slices that were taken from the mice show that inhibition is very much reduced leading them to believe that a lack of inhibition causes tinnitus.

Tzounopoulos says that this opens the door to much more research towards treating the condition. He says that while it was debated among experts what causes tinnitus they can focus on where to go next.