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From a study of recent hearing protector attenuation test data, this work presents a proposal to reconsider how data, gathered by recognized standard subjective test procedures, is used to calculate the single number performance rating of hearing protectors. Current practice is to embed the expected performance (mean) and the variation in performance (standard deviation) in a single rating figure. A proposal is made for clearly separating expected performance from the variation while retaining the use of the current subjective test procedures. This proposal is applicable to all current single number rating systems including SNR, NRR, SLC(80), and the newer ANSI NRS(Ax).

The objective of this study was to investigate how noise-induced hearing loss (NIHL) or noise injury (NI) affects individuals and others of dairy farm communities in New Zealand. Using "grab" or opportunistic sampling at DairyNZ discussion groups and a recreational function, a survey questionnaire was completed by 74 participants from two dairy farming communities in New Zealand. Self-reported hearing difficulties were highlighted by 48% (42) of the 74 participants. The effects of NI on individuals and others included communication difficulties leading to the development of coping strategies, social isolation; decreased employment opportunities, loss of productivity, and increased effort and adjustments by family and work colleagues. Frustration, anxiety, stress, resentment, depression, and fatigue are also negative consequences that may contribute to a loss of quality of life and contribute to further health costs. Increased lateness, absenteeism, sickness and other behavioral aspects were not expressed as normal issues in the workplace, as the majority of the individuals are/were self-employed or working in a family business. This study shows that each year in New Zealand NI results in significant negative social, psychological, and economic consequences for those individuals affected, along with their families, friends, and work colleagues.

Introduction: Hearing loss is a major cause of disability in the world. Occupational noise exposure is likely to contribute to a very high proportion of the cases of hearing loss in adults. Concern has been raised by the Accident Compensation Corporation (ACC) in New Zealand about the fact that the number of new cases of noise-induced hearing loss (NIHL) is not declining, despite the health and safety legislation and establishment of hearing conservation programmes in industry. To inform strategies for prevention, a review of the burden of NIHL in New Zealand was undertaken, particularly focusing on the trends in compensation claims and costs, and the associated sociodemographic patterns., Methods: A review of the peer-reviewed published literature was conducted to identify national and international estimates of NIHL prevalence. The ACC claims dataset (July 1995 to June 2006) was analysed to describe annual trends in new NIHL claims, cost to ACC, and claimants' age, gender and occupational group., Results: There is currently no reliable information regarding the overall incidence and prevalence of NIHL in New Zealand. ACC data reveals a substantial increase in the number of new NIHL claims annually, rising from 2823 in July 1995-June 1996, to 5580 in July 2005-June 2006. Together with ongoing claims the overall costs of NIHL claims increased by an average of 20% each year (a six-fold increase over the decade) resulting in a total cost to ACC of $193.82M over the review period. Collectively, agriculture and fisheries workers, trades workers, machine operators, and assemblers accounted for 53% of new claims. Most claims were lodged in middle age or later, with the vast majority of claimants (95%) being men. The relationship of age with the probability of making a claim changed significantly over the study period with rates in older age groups increasing faster than in younger., Conclusions: The substantial and increasing societal costs despite decades of NIHL control legislation suggests that current strategies addressing this problem are not effective, inadequately implemented, or both.