Ringing in ears may have deeper source
Tinnitus results from brain’s effort to compensate for hearing loss, a study finds
The high-pitched ringing, squealing, hissing, clicking, roaring, buzzing or whistling in the ears that can drive tinnitus sufferers crazy may be a by-product of the brain turning up the volume to cope with subtle hearing loss, a new study suggests. The results, published in the Sept. 21 Journal of Neuroscience, may help scientists understand how the condition arises.
Tinnitus is clearly a disorder of the brain, not the ear, says study coauthor Roland Schaette of the University College London Ear Institute. One convincing piece of evidence: Past attempts to cure the condition by severing the auditory nerve in desperate patients left people completely deaf to the outside world — but didn’t silence the ringing. How the brain creates the maddeningly persistent phantom noise remains a mystery.
Usually, tinnitus is tied to some degree of measurable hearing loss, but not always. “We’ve known for a long time that there are people who report tinnitus whose audiograms are normal,” says auditory neuroscientist Larry Roberts of McMaster University in Canada, who wasn’t involved in the new study. “It has been a puzzle to figure out these exceptions to the rule.”
Schaette and coauthor David McAlpine, also of the UCL Ear Institute, suggest that these exceptions may actually be due to “hidden hearing loss” that shirks detection in standard hearing tests.