As their shouts crescendoed into a roar louder than a jet plane taking off, fans of the Kansas City Chiefs American football team had reason to celebrate: they had set a new world record for the loudest stadium cheer.
That was last September, and in hindsight, the crowd might come to view the achievement in a more dubious light. At 142.2 decibels, the noise had the potential to cause permanent hearing damage.
Until recently, the medical community believed that most hearing loss was caused by hair cells in the ear degrading as we age.
But evidence is emerging that sound levels at sporting events, concerts, nightclubs and on personal devices can cause lasting damage to the connections between hair cells in the ear and the nerves that transmit sounds to the brain (see main story). Over 1.1 billion teenagers and young adults worldwide could be at risk of hearing loss as a result of exposure to unsafe levels of recreational noise, according to a recent World Health Organisation report.
To make matters worse, this kind of hearing loss doesn’t show up on standard tests. Researchers are calling it a hidden epidemic. “We think this problem is incredibly prevalent, but it’s difficult to measure because the tools we have available today are not sensitive enough,” says Konstantina Stankovic, an auditory neuroscientist and surgeon at Massachusetts Eye and Ear, and Harvard Medical School, in Boston.