[NHIL epidemiology in Italy. 20 years from DLgs 277/91: review and expectations]

Digs 277/91 and following related laws brought up a large number of NHILs, but also planned surveillance more and more effective in preventing hearing loss. In these two decades we also saw an inversion in percentages between working populations. The Authors analize these two factors, better and wider prevention and changing in work populations, related to resulting reduction of NHIL's cases. Besides, the Authors compare different insurance scales adopted to evaluate hearing damage in this period, bringing out similarities. INAIL's path achieved another last goal since 2007 in planning the new protocol about hearing aids, aiming to more effective compensation of the recognized hearing loss, looking more at "Biological value" of the person than at former "working capability".