DOES CHOIR SINGING CAUSE NOISE-INDUCED HEARING-LOSS

Although health problems in musicians have been previously reported, n ot much is known about noise-induced hearing loss due to choir singing . However. there are data to show that peak levels of more than 110 dB SPL are produced in choir singing, and major parts of sound energy ca n be found below 1 kHz and even 500 Hz but nut below 100 Hz. To find o ut about possible hearing loss due to professional choir singing, Eve measured the hearing threshold level of 62 choir singers in a large op era choir. Most publications about noise-induced hearing loss report t hat the high-frequency region is impaired most. However, in our study the low frequency region was affected most, when compared with normati ve data (especially ISO 7029). Control groups of women and men with no rmal auditory function did not show pure-tone hearing thresholds diffe rent from ISO 7029. The permanent threshold shifts at 250 Hz and above are most likely noise induced with choir singing as noise source. How ever, hearing losses al 125 Hz and possibly partial at 250 Hz are caus ed by some other effect, An (unproven) hypothesis is that singing migh t lead to increased endolymph pressure, and thus might cause hearing l oss especially in the low-frequency region. Whether more choirs show s imilar hearing impairment and whether singing raises cerebrospinal flu id pressure will be the subject of further investigations.