Detailed tests on 170 students aged 11 to 17 showed almost all engaged in “risky listening habits” at parties, clubs and on personal devices.
More than a quarter of them were already experiencing chronic, persistent tinnitus – a ringing or buzzing in the ears that more typically affects people over 50.
Study co-author Drr Larry Roberts, of McMaster University in Canada, said: “It’s a growing problem and I think it’s going to get worse.
“My personal view is that there is a major public health challenge coming down the road in terms of difficulties with hearing .”
Further testing of the same subjects – all students at the same school in Sao Paulo, Brazil – showed that even though they could still hear as well as their peers, those experiencing tinnitus were more likely to have a significantly reduced tolerance for loud noise.
This is considered a sign of hidden permanent damage to the nerves that are used in processing sound, damage that can foretell serious hearing impairment later in life.
Dr Roberts said that when the auditory nerves are damaged, brain cells increase their sensitivity to their remaining inputs, which can make ordinary sounds seem louder.
Increased loudness perception is an indication of nerve injury that cannot be detected by the audiogram, the standard clinical test for hearing ability.
Research indicates that such “hidden hearing loss” caused by exposure to loud sounds in early life deepens over the years, worsening a person’s hearing ability later in life.
Dr Roberts said the only solution is prevention.
“The levels of sound exposure that are quite commonplace in our environment, particularly among youth, appear to be sufficient to produce hidden cochlear injuries,” he said.
“The message is, ‘Protect your ears.’”
Source: By Stephen Beech
photo credit: Dreamstime