Asked by: Lukasz Musialowicz, London
Doctors have long warned of the damaging effects of prolonged exposure to loud music via earphones. The popularity of portable cassette players in the 1980s led to studies claiming that around 1 in 20 people were risking Noise-Induced Hearing Loss.
Yet while there is no doubt that exposure to loud noise from, for example, machinery can lead to permanent damage, evidence that music from portable devices does the same has remained elusive. That’s changing, however, as scientists focus on finding actual physical damage to nerves. Dr Martine Hamann and colleagues at the University of Leicester recently published the first evidence of such harm, by showing that loud noises strip nerve cells of their protective coating, preventing them from reliably transmitting signals from the ear to the brain.
This confirms previous studies showing that even brief exposure to loud music can reduce the sensitivity of the ear. But the finding also explains why evidence of permanent damage has been elusive. Dr Hamann found that nerve cells repair themselves, replacing the outer layer after a few months – if they’re given the chance.