[Noise and hearing].

The injuries induced by noise to auditory system affect above all the inner ear. Thus the hair cells forming the most fragile structures of the sensorial neuro-epithelium will suffer from hair disturbances. As a result these lesions will reduce hearing acuity and sensitivity leading to noise induced hearing loss. There are two types of hearing loss. The sudden hearing loss, called acute sonorous trauma, or the insidious one due to industrial-like noises. On the other hand, noisy environments may have some effects on the intelligibility known as effects on the recognition of speech. To conclude, the epidemiological studies carried on all sections of the population, including teen-agers, revealed a worrying yielding of their hearing performances, probably resulting from excessive level of noisy surroundings as supposed some years ago by Glorig.