NAGOYA (Kyodo) Extensive exposure to loud noise from earphones causes hearing damage that is difficult to detect at an early stage with standard auditory examinations, according to a study by Japanese and German researchers.
Listening to loud music through earphones can subtly damage one's ability to filter out sound signals in a noisy environment, but this can't be detected by conventional tests, in which the subject tunes in to separate sounds in a quiet room, says the study published online Wednesday by the U.S. science publication PLoS ONE.
Hidehiko Okamoto of the National Institute for Physiological Sciences said people should lower the volume on music players by using noise reduction and other features. She also said the findings show that auditory tests should be held in noisy environments, too.
The study warns that loud earphones can lead to future irreversible hearing disorders.
The team studied 13 people in their 20s who use portable music players at high volumes for a long period and 13 people who do not.
Research on their brain reactions to specific frequencies indicated no difference in auditory ability in reduced noise environments, but in noisy environments the group exposed to loud music showed slower brain reactions and weakened ability to distinguish sounds.