Occupational deafness: the continuing challenge of early German and Scottish research.

Systematic studies in occupational deafness were first carried out in the late 19th century, in America, Germany, Russia, and Scotland. The studies by Gottstein and Kayser, in 1881 in Germany, and by Barr, in 1886 in Scotland, are identified as the two principal landmarks. The physicians who carried them out should be seen as occupying a place in the mainstream of development of industrial medicine. Gottstein and Kayser's study of personnel in a railway works reflected a contemporary concern about railway safety; Barr's, of boilermakers, a feeling for the difficulties in hearing in the everyday world experienced by the victims of occupational deafness. Barr's evaluation of such difficulties through self-report, we argue, reveals more of the quality of hearing handicap than the present century's apparently objective tests. Both studies relied on occupation-based epidemiology, which was able to identify occupational deafness, distinguish its etiology, and locate the site of its pathology. We argue that occupation-based epidemiology has since been neglected in favour of dose-response epidemiology to the detriment of research in occupational deafness and in industrial medicine generally. Dose-response epidemiology seems the more scientific but, in practice, it is afflicted by even more uncertainty than occupation-based epidemiology. To compound the uncertainty, there are two incompatible mathematical expressions for the dose-response relation for noise, both separately enshrined in legislation in various parts of the world. We conclude by advocating more secondary research in industrial medicine. Barr points us to a further topic for such research, the place of temporary threshold shift in the development of knowledge about occupational deafness as a problem for industrial medicine.