Hypoacousie due au bruit : la réglementation évolue

Abstract

Les déficits auditifs dus au bruit comptent parmi les premières maladies professionnelles dans les pays industrialisés, que ce soit en nombre ou en coût de compensation financière, car ces atteintes sont irréversibles. En France, ce sont en moyenne 6,8 % des travailleurs qui sont soumis à des bruits nocifs. Sur les 5 millions de Français ayant des problèmes auditifs, 2 millions sont âgés de moins de 55 ans. Les signes de souffrance auditive ou d’alerte sont notamment des difficultés à la compréhension en milieu bruyant qui peuvent s’ajouter aux effets de la presbyacousie. Une récente directive européenne, applicable dès février 2006, abaisse le niveau maximum de bruit admissible de 90 à 87 dBA (soit une intensité sonore diminuée de moitié), et introduit un niveau déclenchant un plan de prévention à 80 dBA. Enfin, le tableau relatif aux surdités professionnelles a été récemment modifié. Cette modification du calcul de l’indicateur médico-légal sera susceptible de multiplier par 4 le nombre de surdités professionnelles qui pourraient bénéficier d’une compensation financière.

Noise-induced hearing losses (NIHL) are among the most often encountered occupational diseases in many industrial countries. This is true in terms of the number of exposed workers and in the amount of health insurance or State health care compensations. These handicaps are not reversible. In order to understand why this is, we will explain how high levels of noise pressure can affect the ear, by describing the three parts of the ear, including some details about the inner ear and its sensitive cells. Several epidemiological surveys indicate that an average of 6.8 %, French employees are exposed to dangerous levels of noise with vast differences according to their sector of activity. The most exposed are found in the wood and paper industries (37.4 %), in large plants and amongst intermittent workers. Males are five times more exposed than females, but they are much more numerous in these industries. About 5 million French people suffer from hearing disorders; 2 million of them are under 55 years of age. The Labour Ministry controls the occupational medicine services where exposed workers are subjected to a special check-up, which includes an audiometric examination at least every two years. But for the others, it is useful to know the danger signs of hearing disorders, like hearing fatigue (TTS), tinnitus or difficulties in understanding with background noise. Aging also affects hearing capabilities: this is called presbyacusis, which can be a confusing factor in the assessment of NIHL in older workers. In order to improve the protection of all workers in the EC, a recent European Directive will decrease the maximum level of tolerated noise (from the current 90 dBA) to 87 dBA before March 2006. In addition, the level at which a preventive programme has to be developed (hearing conservation programme) will start at 80 dBA instead of the current 85. The French compensation system for workers suffering from NIHL has also recently been modified. Such a modification will increase the number of compensations (probably by 4 times). The annual cost of the aforementioned compensations was 100 million € in 2003.