[Assessment of noise damage-part 1 : Occupational fundamentals of causal attribution]

Noise has the potential to exert a harmful effect on the auditory system. Whether damage actually results depends primarily on the individual susceptibility of the auditory system as well as on the intensity and duration of exposure. Occupational noise-induced hearing loss typically develops over years to decades of hazardous exposure, affects only a subset of those exposed, and is irreversible. To assess whether an insured activity constitutes a health-relevant noise exposure in terms of causal attribution ("Einwirkungskausalität"), a fundamental understanding of physical and technical parameters is required; a medical diagnosis alone is insufficient for establishing causality. In part 1 of this article, the fundamentals of exposure assessment and causal relationship (e.g., daily noise exposure level normalized to 8 h [L_EX,8h], single event sound exposure level [L_AE], effective noise dose [ELD]) are outlined, while part 2 addresses the medically professional requirements for recognizing occupational noise-induced hearing loss as an occupational disease under item 2301 of the Occupational Diseases Ordinance (BKVO).