Test of hearing loss and hearing impairment in employees com- plaining of noise annoyance

Complaints of noise annoyance are increasing in several areas of the working environment, particularly in open offices, schools and kindergartens. The noise levels seldom reach noise levels with risk of noise induced hearing loss, but the cause emerges from a complex interplay between the level and the character of the noise, the acoustics of the workplace, psychosocial stress-factors, and individual factors including hearing ability. Among the main problems are the acoustic quality of the rooms, and the hearing ability of the employees. With longer life expectancy and a change towards service jobs with high communicative and high cognitive demands, it is important that the working environment does not exclude employees with reduced hearing abilities, who have great difficulties in hearing in noisy surroundings of low acoustic quality. Another trend in hearing ability is reduced hearing among adolescence, which seems to be serious with the expectancy of a longer working life. Regular tests of hearing thresholds in noise exposed employees are required all over the world, but the audiogram may not determine minor deficits in hearing or initial signs of noise induced hearing loss (Attias et al. 2001; Torre et al. 2007). Oto-acoustic emissions (Job et al. 2007) and suppression of oto-acoustic emissions (Zhang et al. 2007) may be a valuable tool in measuring the plasticity of hearing, but further validation is needed. If a greater number of subjects have to be tested, it is also necessary to introduce time optimized protocols (Sisto et al. 2007). We have tested these methods in a binaural setup, and will present a series of decisions, which has to be made in order to do assessments in the field.