Researchers Pinpoint Cause of Tinnitus
People who suffer from a phantom and constant ringing in their ears – a condition known as tinnitus – had long been told the noise was all in their head.
It turns out, it is.
A research team from McMaster University in Hamilton and several other universities in Canada and the United States have pinpointed the source of the often debilitating condition that affects millions of people worldwide and has a dramatic impact on the quality of their lives.
In an article published in the latest edition of The Journal of Neuroscience, scientists report that the tinnitus sound – described by many sufferers as a constant high-pitched ringing or hissing noise – is generated by neurons firing in the brain, not the ear.
“We found that tinnitus is generated not in the ear but by changes that occur in the brain when hearing loss occurs,” said Larry Roberts, a neuroscientist and the lead researcher from McMaster. “It’s hearing loss associated with noise exposure that causes the majority of the cases.”
The research was conducted in conjunction with scientists from the universities of Calgary, Southern Illinois and Michigan, the Cleveland Clinic and Harvard University.
Roberts said that through studies on animals, research showed that if the auditory nerve of a tinnitus sufferer is severed, the condition doesn’t disappear. That means the root of the issue lies not in the ears, but in the brain, he said.
And while the condition has been attributed to everything from loud noises, to antibiotic use and stress, no definitive cause or cure has been found, said Roberts.
Roberts said the new research also doesn’t mean a cure is imminent.
And without a cure, Roberts said, the condition can drive people to depression or even suicide unless they are able to get used to the noise and dislocate themselves from the emotional stress.
Most famously, the phantom ringing of tinnitus has been theorized as the reason why 19th century painter Vincent van Gogh cut off his own ear.
For Elizabeth Eayrs, a former Toronto city councillor and the founder of the Tinnitus Association of Canada, she said she felt like she couldn’t go on when she was first afflicted in the mid-1970s, after heading home from a particularly raucous council meeting.
“It was as though there were large rocks or stones being shifted back and forth in a metal container,” she said. “But each person has a unique sound.”
Described as a high-pitched tone by most, Eayrs said it is also heard as frying, sizzling, steaming, or even a low roaring, like a diesel truck running continuously.
But the 83-year-old Eayrs said she has gotten used to the rumbling that never stops.
“As I get older, it’s almost like I’m forgetting about it,” she said.
And her story is not uncommon.
The Tinnitus Association of Canada estimates there are approximately 360,000 people with the condition in Canada, of which 150,000 find it debilitating in some way.
And in the U.S., tinnitus is the No. 1 service-connected disability of veterans returning from Iraq and Afghanistan, totalling 760,000 vets at the end of 2009.
While numbers on Canadian veterans weren’t readily available, Zofia Wald-Mroz, an audiologist at the Perley and Rideau Veterans Health Centre in Ottawa, said a number of soldiers returning from Afghanistan have sought help.
“They are exposed to an incredible amount of noise from gunfire, helicopters and concussive explosions that make them vulnerable to problems with their ears,” she said.
Roberts said there may also be an increase in cases of tinnitus as a consequence of mild hearing losses, especially among young people who are growing up in a generation where earbud-style headphones are commonly used.
“It’s not strange to sit on a bus or the subway and hear somebody with music blaring from their headphones,” he said. “They might not pay the price now, but they will later.”
Source: Delta Optimist